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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: JimGnitecki on May 19, 2009, 01:10:23 PM
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This posting is all about how a REASONABLE computer model can be created for important bus performance attributes, even when the data available is incomplete or rough.
What I was trying to do was to see if I could answer a few basic questions about the likely fuel mileage performance of the 1979 Eagle conversion bus I recently acquired as the new fulltiming home for me and my wife. Specifically, I wanted to know:
- What fuel mileage is likely given this bus’s engine, driveline, and weight?
- How much does the fuel mileage change as cruising speed is increased?
- What is the highest sensible cruising speed, assuming a really nicely engineered highway with high speed limits? (We have a 200 mile section of I-10 in Texas that is posted at 80 mph speed limit, if fuel cost is not an issue!)
- Was the fuel consumption I experienced on the maiden voyage, from where I bought it in Florida, back home to Texas, typical of what I should expect?
Here is the data I currently have available, or have been told:
- The engine in the bus is a Detroit Diesel 8V71 with supercharger but no turbo or intercooler
- The engine HAS been modified from its original as-delivered state of tune (272 hp at 2100 rpm). I know this for several reasons:
o The dealer I bought it from says it is in “318 hp” tune now
o I have seen 85 mph on the speed when my attention wandered on the interstate
o A 40 foot, 34180 pound bus with 8” roof rise, mechanical “always driven” fan, add-on power steering, and only 272 hp can’t go that fast
o The speedo was tested versus interstate mileage markers and the error is minimal
o I have invoices paid by the prior owner that show size “N65” injectors, which are consistent with the 318 versus 272 hp tune
- The factory as-delivered gearing was 3.73, and there is no documentation to suggest that the gearing was ever altered
- Per the Toyo tire website, my 11R24.5 M147 bus tires turn 478 revolutions per mile
- My bus has the the Allison HT740 automatic transmission, and I was able to get the gera ratios for that transmission from several different sources
- The fact that the bus hits 85 mph, with the transmission, gearing, and tires it has means that the engine governor speed, originally 2100 rpm, had to have been altered, since that requires doing 2526 rpm at 85 mph with the stock 3.73 gearing, and would require 2275 rpm at 85 mph with even the nominally available 3.36 gearing found on some Eagle buses.
- The bus’s carefully measured maiden voyage encompassed 74 hours, covered 1149 odometer miles, consumed 230.5 GROSS gallons, including the fuel used to run the generator for 63 of the 74 hours, and despite the discovery late in the voyage that the air filter badly needed replacing (it actually started to collapse during the last hour or so on the road!)
- I have, courtesy of several members of this forum, Detroit Diesel data and graphs that provide the power, torque, BSFC, governor speeds, and injector sizes for a huge number of V71 engine variants, and that include data on versions governed to 2500 and even higher engine rpm
- I have a copy of the Caterpillar booklet “Understanding Coach / RV Performance”, which includes a lot of data and charts on road and wind resistance versus speed, engine cooling fan power consumption, the effect of highway grades, and generator fuel consumption.
Is this enough to build a reasonably useful and reasonably accurate computer model? As it turns out, yes!
Below are 2 charts of data. They differ in one significant assumed parameter: The first one assumes the as-delivered rear axle gearing ratio of 3.73, while the second one explores what would happen if the axle ratio were to be changed to 3.36 (a commonly suggested “improvement” for those who want better fuel mileage from their buses). Let me walk you through them.
The first data line shows the gear ratio, either 3.73 or 3.36.
The next line shows the assumed weight of diesel fuel, which varies by ambient temperature and by formula changes, but averages 7.15 lb per gallon, which is what I assumed here.
Then, I list the gear ratios within the 4-speed Allison HT740 automatic transmission on my bus.
The first column of data then shows speed in miles per hour.
The 2nd column shows the lowest gear that can be used at that speed.
The 3rd column shows the corresponding engine rpm at that speed. This is calculated for each MPH row by using the axle ratio, Allison gear ratio, and tire revs/mile.
The “BSFC” column shows the “brake specific fuel consumption”. That is an engineering term that measures how many pounds of fuel are used by a specific engine per horsepower-hour produced. For most gasoline cars, the BSFC ranges from 0.4 to 0.6. For diesel buses, it ranges from as high as 0.45 for some engines at certain operating rpm, to as low as 0.35 for other engines at their optimal engine rpm for best fuel efficiency. The more modern 5-stroke, electronically controlled engines tend to run closer to the 0.35 number, while my 30 year old Detroit Diesel, high rpm, 2-stroke engine NEVER gets better than just above 0.40, and is as bad as 0.46 at unfavorable engine rpm. What does a BSFC of 0.40 mean? It means that the engine will burn 0.4 pounds of fuel per hour for each horsepower produced.
So, for example, if we needed 150 hp to run at 55 mph under certain highway conditions, the engine would be burning fuel at the rate of 150 x 0.40 = 60 pounds per hour. That 60 pounds per hour would in turn translate to 60/7.15 = 8.4 gallons per hour. THAT would in turn translate to 55 MPH / 8.4 gallons/hr = 6.6 mpg. This is just a fictitious example, but it shows you how the math works.
The “HP req’d at wheels” column shows the total horsepower required (road friction plus air resistance), at the WHEELS of the bus, AFTER all frictional and accessory drive losses have been deducted from the “gross” power output of the engine at that road speed. This means NET power required AFTER driving the engine cooling fan, the power steering, the alternator, and the bus AC (mine doesn’t have bus AC), and after all frictional losses through the transmission and rear axle. This data comes from the Caterpillar booklet, and specifically assumes a bus of 34,000 pounds, with frontal cross sectional area of 90 sq ft, and a coefficient of drag = 0.60.
The “Fan HP” column approximates (!!) the power diverted from the wheels to instead drive the engine cooling fan. This is a surprisingly BIG number on any bus, and a particularly big number on any bus where the fan is ALWAYS driven in direct proportion to engine rpm (like on my bus). Some modern buses have hydraulically driven fans, which can run at speeds NOT proportional to engine rpm, or can even be entirely “turned off” by the electronic control system, and such fans use a lot less power since they only run when the electronic control systems know they are NEEDED. I had to approximate the fan numbers for my bus, since Detroit Diesel does not provide them, so I used the values from the Cterpillar booklet with one deviation: Caterpillar normally runs its mechanically driven fans at about 1.25 times engine rpm, but I checked my actual Detroit Diesel bus installation, and mine runs at engine rpm (driven pulley size = driver pulley size, and miter box ratio appears to = 1 to 1).
The “HP req’d total” column simply adds the fan hp to the hp required at the wheels to give a TOTAL hp that the engine must produce after all internal, transmission, and accessory losses and diversions.
The “HP avail” column uses the engine rpm calculated in the 3rd column, and “looks up” what power the engine produces at that rpm, according to Detroit Diesel. Here, I ran into a significant need for a reasonable set of assumptions and approximations, since my engine is (a) modified in its tune and (b) appears to be governed to 2500 rpm or higher.
This is not as hard to resolve as you might imagine. First, power is simply torque at any given rpm multiplied by the rpm, and divided by a numerical constant to convert it into “horsepower” (as opposed to say “watts”). The formula is in fact:
HP = Torque x RPM / 5252.
Thus IF torque was constant over an RPM range, if you increase the RPM from 2100 to 2500, you would get 2500/2100 = 1.19 times as much power. However, torque is NOT constant over an rpm range for most engines, and in fact, on the Detroit Diesel 8V71, it is FALLING in the rpm range from 2100 to 2500. However, we can reliably estimate it by using 2 different methods, and taking the more conservative to be, if anything, a bit pessimistic.
The first method is to study the Detroit Diesel charts (good for getting yourself to sleep when you have insomnia!), and noting that for engine variants where everything is the same (including injector sizes) except for governor speed, the engines produce on average 13% more power when spun to 2500 versus 2100. With the 318 engine variant, that leads you to about 1.13 x 318 = 359 hp.
The second method is to manually “extrapolate” the falling, curved shape torque curve to 2500 rpm, and then calculate the power at 2200, 2300, 2400, and 2500 rpm based on that extrapolated curve. With the “318” engine version, that leads you to about 338 hp.
Let’s conservatively assume the 338 hp versus the 359 hp. That way, our model will, if anything, UNDERestimate versus overestimate what we should expect our bus to be able to do. That leads to the numbers you see in the “HP avail” column.
In the “MPG” column, we simply take the BSFC, multiply by “HP req’d total”, divide by 7.15 to convert from pounds of fuel to gallons, and divide into MPH to get MPG.
The next column, “HP for hills & accel” simply takes the available power, subtracts the total power required to run down the highway and turn the cooling fan, and shows you how much power is left over to handle uphill grades, headwinds, and acceleration for passing other vehicles. I regard this number to be as important as the MPG number, since a bus that gets great fuel mileage but cannot climb even moderate hills or fight reasonably foreseeable headwinds, is not going to be much good.
The last column adds in the fuel mileage impacts of running the generator while driving down the highway. The Caterpillar booklet says that 0.5 gallon per hour is a reasonable assumption for a moderately (not fully) loaded generator, and that is what I have used.
Let’s look now at some of the findings and predictions that this modeling produces.
(http://i252.photobucket.com/albums/hh16/JimGnitecki/Fuelmileagemodel2009-05-19a.jpg)
(http://i252.photobucket.com/albums/hh16/JimGnitecki/Fuelmileagemodel2009-05-19a336vs373.jpg)
First, note that if my engine was still governed to 2100 rpm, 3rd gear could not be engaged at much above 50 mph. With a 2500 rpm governor, it can be engaged to about 60 mph, when necessary to help climb a steep grade. This means that with the higher governor setting, assuming the Allison can be configured to shift at the higher road speed, I would have a better chance of maintaining a speed closer to that of cars and light trucks when climbing a 60 mph highway hill in traffic.
Note also that running a Detroit Diesel 8V71 at low rpm does NOT improve BSFC, but rather hurts it significantly. In fact, the best BSFC occurs at around 1900 rpm. This is very different from modern 4-stroke electronically managed engines, which Caterpillar states achieve their best BSFC at around 1400 to 1500 rpm.
Note how HIGH the power requirements are for pushing a bus down the highway at elevated speeds. Basically, the power required increases roughly proportionately to the CUBE of the speed, since air resistance is the largest component of total resistance at highway speeds. Note that a “stock” 272 hp engine would have no chance of driving the bus to 85 mph – even before allowing for the power diverted to run the cooling fan. In fact, a 272 hp engine output would not even be sufficient to hit 80 mph.
Note how the MPG falls swiftly as speed increases. To illustrate dramatically the difference, I appear to have the choice of achieving 8.4 mpg at 55 mph, or getting to my destination a lot faster by suffering with a 5.3 mpg average at 75 mph – a 37% degradation in fuel mileage in order to go 36% faster. This is not that awful, but is only this “good” because the BSFC on this specific engine is actually EQUAL at either 55 mph or 75 mph, because the 8V71 likes high rpm!
To compare 2 slightly more likely scenarios, I can get 7.5 mpg at 60 mph or 5.9 mpg at 70 mph. That’s a 27% fuel mileage improvement for going 14% slower.
The numbers in the “HP for hills & acceleration” column are pretty compelling. “Reserve power” for hills and acceleration falls off noticeably beyond 70 mph, while being quite impressive at 60 mph.
Note the “skewed” effect of running the generator on the fuel mileage – its impact is far greater at lower speeds than at high speeds. This is simply because the generator fuel consumption rate is basically CONSTANT regardless of road speed, so the faster you drive over any given distance, the less time the generator has to run to keep the AC and other conveniences running. Note that for this reason it is WILDLY inaccurate to say that the generator costs you “x” miles per gallon, where “x” is any fixed number. It’s just not so.
There’s another set of numbers UNDER the main table, which is labeled as “Sums (area under the curve0” and as “Averages”. This is merely a simple and graphic way to try to measure the ENTIRE AREA under the curve for each of the columns, or the average for each column. These numbers only take on significance when you compare them for the “3.73” gearing versus the “3.36” gearing. THAT is interesting in the extreme.
Note that the “area under the curve” and the “average” for “HP available”is 6.3% higher with the 3.73 gearing versus the available 3.36 gearing. In other words, the bus would feel 6.3% weaker with 3.36 gearing than with 3.73 gearing. Those of you who are hotrodders will understand that a 6.3% difference is BIG – readily detectable in the “seat of the pants”.
Much more surprising is that the fuel mileage average with 3.36 gearing is NOT appreciably better than with 3.73 gearing. It is in fact projected at only 6.6 mpg versus 6.4 mpg, averaged across the 55 to 85 mph range. That 0.2 mpg difference is pretty inconsequential. Note that at 55 and 60 mph, it is only 0.1 mpg different, which is even less consequential. For this I should give up 6.3% of my usable power?
The case for the 3.73 becomes even stronger when you look at the hp available for hills and acceleration. There, the 108 hp average with 3.73 gearing is 12.5% better than with the 3.36 gearing. That kind of difference makes a bus feel like an entirely different bus!
Conclusion: Numerically lower gearing is NOT always a good way to get better mileage. In fact, with this “high rpm” 2-stroke Detroit Diesel engine, it could be argued to be precisely the WRONG thing to do.
There’s one more point to address: how truly accurate and real world is this “modeling”, which is after all based on a combination of incomplete or approximate data from different sources, coupled with some reasonable assumptions and extrapolations?
Well, now that you ask, it IS pretty accurate.
Remember that earlier I said that the maiden voyage for my bus encompassed 74 hours (Monday early morning through Thursday mid morning), covered 1149 odometer miles, consumed 230.5 GROSS gallons, including the fuel used to run the generator for 63 of the 74 hours, and despite the discovery late in the voyage that the air filter badly needed replacing. Let’s examine this data and compare to the modeling projections.
My trip was done trying to maintain 73 mph wherever possible. Naturally, I had to reduce the speed where the speed limit on the interstate was lower, and I did run into traffic briefly at a few points on the trip. I also found myself doing 80 to 85 mph sometimes, when my attention on speed briefly wandered. I also did have a significant headwind for a few hours on the first day on I-10. But, the vast majority of the trip was done at the 73 mph, and the majority of the trip was done under wind conditions that did not represent a significant adverse load. And yes, there were hills, but not an unusual number of them – certainly nothing like a mountainous area that would seriously skew the mpg results.
IF we incorrectly ignore the generator hours, we calculate mpg for the trip at 1149 miles / 230.5 gallons = 4.98 mpg. However, if we take into account that the generator ran for 63 hours, and assume that Caterpillar is accurate in estimating 0.5 gallons / hour, then the generator consumed 63 x 0.5 = 31.5 gallons of the fuel. That means that the engine consumed 199 gallons. That means the ACTUAL fuel mileage was 1149 / 199 = 5.8 mpg.
Looking at our table for the 3.73 gearing, we see that at 70 mph, the model predicts 5.9 mpg, and that at 75 mph it predicts 5.3 mpg.
I’d say that the model is in reasonable agreement with the actual measured results.
Note that if I had been willing to drive at 60 mph, I could have achieved 7.5 mpg.
I’m looking forward to doing MORE modeling, and learning many more things. :)
Jim G
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71.5 pounds per gallon? Very interesting approach to the beginnings of a perfect world, now how did you factor in cross winds, head winds, the weight of your foot in sneakers as opposed to red wing boots, I'm assuming that is on a perfectly flat road with no corners, I'm sorry if I sound sceptical but frankly I think your spinning more wheels than are needed. My 81 iggle with a 6-92 has no problem hitting 85 and I'm a lot heavier. My only figuring comes in when I fuel up and I've done that over and over in the past 6 years with this particular bus. Just too many variables that don't seem to be factored into the ideal computer program but I do see where it would keep a person entertained for a while, I even know people that build LED lights without resisters, (omg), just because a person says it can't be done doesn't make it impossible, I'm curious to hear what the bus mechanics and the seasoned old timers that turn the wenches everyday think about the program. I know how heavy my foot has to be to get a nice 7.1 MPG and I know what to do to change it to 5.8, just comes with the doing.
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Cody: You didn't metnion which version of the 6V92 you hsve, but the data I have seen suggests that the least powerful 92 makes 335 hp, so the 85 mph is certainly attainable.
The BSFC of the 92 series is notably better than that of the 8V71N, with the very first Detroit Diesel graph I looked at for one showing a BSFC of betetr than 0.35 - BUT at a lower rpm (about 1500 rpm).
If you prefer to find things out experientially, hey, that's no problem for me. I like to analyze things a bit in case there are elements that are not obvious, and I also like to be able to predict results before I try things, as that sometimes leads to better results or passing on ideas that a bit of analysis shows might not be great. :)
Jim G
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This is fascinating stuff Jim. I'm a big fan of financial models so, unlike Cody, I see no reason why this stuff couldn't be modelled for our busses as well. Cody is right, there are a lot of variables, but some of them are so insignificant contributors to overall mileage as to be ignored. The fan HP is a fascinating number - I've heard estimates as high as 40 HP in the past and your charts appear to confirm that. With that number in mind its not hard to see why the guys who try to run some mickey mouse electric fan setup run into trouble. I'll be watching for further empirical evidence to support your model before I try creating my own but thanks for the detailed explanation. Any chance you want to share your model? (he says as he tries to avoid the work of starting from scratch) ::)
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Everything Bob said. 8)
If I have read it said once, I have read it said.......lower the rpm to gain efficiency. Your figures are useful to me in that I would have gone to 24.5 tires from 22.5 and "lost" mpg for my trouble. Now that is going to a lot of work and expense for me to shoot myself in the foot. I like to do that for way less money for it to be any where near cost effective.
Thank you for what you have done here. I might have been capable of that back when I was breezing through Calc with a 4.0 but those days of thinking that deep are long gone and probably soon to be forgotten completely. If you can find the time I have a suggestion for you: figure out what you can do with that fan efficiency. I talked with a knut a long while ago that upgraded his cooling sys to significantly enhance his MPG and wheel HP. He drove the fan through a heat modulated clutch and I understand that those aren't all that rare these days. He also installed a "very efficient" fan and just what, where, how and when is that? And lastly, he installed a really over sized radiator so he wouldn't have to move the air so fast and I think that has something to do with the "cube rule for velocity". I could kick myself for forgetting his name but I also remember that he was getting 10+ mpg with an auto 740. I think he cut the hp consumption of the cooling system by 50% so I guess he saved 20 hp.
Does any of this compute to you? I think this is one of the very few options to get better MPG as NOBODY is ever going to slow down. ::) :P :D :D
Thank you for your work and sharing it with us/me. You have improved things most certainly. And again, what Bob said.
Thank you Sir
John
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"o A 40 foot, 34180 pound bus with 8” roof rise, mechanical “always driven” fan, add-on power steering, and only 272 hp can’t go that fast"
I have to disagree with this statement. Our 34,800 pound MC-8 (8" roof raise) with a tired 272 HP 8v71, Allison 740 transmission, 3.73 rear end, factory power steering and fan govererned to 2550 hit 84 MPH on a smooth flat (new blacktop surface) road in Florida at 14 above sea level, ambient temperature low 80s, and humidity probably near 90%. This speed was confirmed by my speedometer, my GPS, and a friends speedometer & GPS that was following me. Jack
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John: I agree that attacking the mechanical, always on, always engine-rpm-proportional fan is a great place to begin to find REAL gains in both fuel mileage AND hillcolimbing/passing power, and that improving the effectiveness of the radiator is a good second place to go (if the radiator does a better job of cooling, the fan can turn slower).
The benefits would include not only better fuel mileage and more available power, but also the potential to INCREASE the engine's produced gross power,as the limiting factor for most bus engines is not air flow or fuel flow ability, but rather the inability to shed HEAT fast enough to enable higher peak power ratings. In other words, Deetroit Diesel and other manufacturers COULD easily flow more fuel and more air through an engine, but their concern is the ability to shed the extra heat produced along with more power.
I've not yet had time to even THINK about what could be done with the engine cooling fan, but ideas to creatively brainstorm include:
- A kit to change a belt driven fan to one driven by a variable speed system that taps enginepower only when it is NEEDED, and to the extent needed, to drive the fan. An electrically driven fan is out of the question, since a 30 to 40 hp motor is costly, big, and would consume WAY too much 12 volt power (40 hp would require 30 kilowatts even at 100% conversiuon efficiency, and that means an absolute MINIMUM of 2500 amps!!!). An engine driven hydraulic system that could also power the power steering, and whose parasitic load could be controlled to only what is NEEDED at any point in time, is potentially viable.
- A really GOOD fan shroud system that ensures that ALL the air pulled by the fan comes through the radiator
- Side scoops to ram more air into the radiator at highway speeds? Bonus benefit: when it is raining, you also get water cooling the radiator via rapid evaporation on contact. On a 102 wide bus, these would need to be recessed into the bodywork, but on a 96 wide bus, they could be external and thus even more effective.
- A constant or load sensitive water spray system that adds heat loss via evaporation to the radiator (the bus companies used to do this on the Nevada desert runs, didn't they?)
-A second radiator on the rear or passenger side? Even without a fan, it would help take out more heat.
- On a Detroit Diesel, the unused fuel is recirculated back to the fuel tank, and thus is used to cool the injectors and head. Would it help a tiny bit to pass the heated fuel through a fuel radiator before dumping back into the fuel tank?
and other stupid ideas . . . :)
Jim G
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"o A 40 foot, 34180 pound bus with 8” roof rise, mechanical “always driven” fan, add-on power steering, and only 272 hp can’t go that fast"
I have to disagree with this statement. Our 34,800 pound MC-8 (8" roof raise) with a tired 272 HP 8v71, Allison 740 transmission, 3.73 rear end, factory power steering and fan govererned to 2550 hit 84 MPH on a smooth flat (new blacktop surface) road in Florida at 14 above sea level, ambient temperature low 80s, and humidity probably near 90%. This speed was confirmed by my speedometer, my GPS, and a friends speedometer & GPS that was following me. Jack
Jack: For reasons described in my posting above, an 8V71 nominally rated for 272 hp is making way more than 272 hp when spun to 2550 rpm. Although the torque curve does fall with rpm in the 2100 to 2550 range, you ARE still spinning faaster enough to make lots more power than at 2100. Take another look at that section of my posting. I was even CONSERVATIVE in what I estimated an 8V71 could make at 2500 rpm.
The 14 feet above sea level is also as close to ideal as you can get (diesels don't eprform well BELOW sea level because they like air, not water :) ), as the air density is highest at sea level.
And old Detroit Diesels don't seem to lose power with miles. These are very robust engines. Mine does not even make oil smoke on startup, and it was in service as a commerical bus for 16 years before it was converted!
Now you have me curious though too. I know it is absolutely stupid, but I am tempted to drive the 150 miles or so to that section of I-10 in West Texas that is posted at 80 mph, and see how fast the bus could actually go! Unfortunately, trucks and buses are restricted to a lower sped there, and a ticket for 15 or 25 mph over the limit could be a financial disaster AND get me a heck of a lecture on public safety from a state trooper! I wonder if drag strips allow buses, and what speed a bus could hit in just 1/4 mile. :)
Jim G
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I wonder if drag strips allow buses, and what speed a bus could hit in just 1/4 mile.
Ed Skiba ran his bus on the 1/4 mile Diesel Drags in NJ, and even won a trophy! I don't rememebr what speed he hit or his time.
When my bus hit 84, it was still climbing very slowly, but I decided I was already going much faster than I should. I just wanted to see how fast it would go and this was on a 6 mile straight strecth
of new road surface with no traffic, except the friend that was following me. At 84, I lifted out of the throttle and started slowing. A front blowout at that speed (tires are rated for 75) would have probably been fatal. We usually try to manitain a speed of 62 MPH. Jack
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A lot of the 6V92TA engines are set up as "coach" at the 277 hp setting. Mine is.
My bus cruises on flat terrain at 64 mph.. It can go 75 mph on a good day.
315-80R22.5 Tires. Ht 740 Mechanical, 6V92TA (MUI) New Jersey.
I did have it up to 95 mph "ONCE".. Downhill before I hit the chicken pedal.
Fuel mileage over 3,000 miles worked out from 5.5 to 7.6 mpg depending on road-n-load
so I am happy for anything over 5 mpg....
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When we had our first motorhome years ago, there was a rather famous story circulating about an engine warranty claim denied on a new coach being delivered by a delivery driver, where the engine was rather greviously damaged by a downhill speed run in which it hit a speed well into triple digits. The onboard computer recorded the event. :)
Governors can prevent a diesel engine from overspeeding via the application of too much throttle pedal. They can't stop it from being overreved via being forced into too low a gear or via a downhill run, or via "runaway" due to it feeding on its own oil via a failed blower seal or other means!
Jim G
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I guess the obvious question that nobody seems to be asking is, jim, what is your background, you seem to be wanting to be the utmost last word on anything diesel, so far you have questioned and contradicted some of the top diesel mechanics and nobody is asking the background question so I will. lol, not trying to be difficult here but your sounding a lot like a textbook and not a bit like a mechanic, so what gives.
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Lighten up Cody. I haven't seen anybody contradict anybody. What I have seen is a fresh approach to a question that gets asked here pretty regularly.
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"o A 40 foot, 34180 pound bus with 8” roof rise, mechanical “always driven” fan, add-on power steering, and only 272 hp can’t go that fast"
I have to disagree with this statement. Our 34,800 pound MC-8 (8" roof raise) with a tired 272 HP 8v71, Allison 740 transmission, 3.73 rear end, factory power steering and fan govererned to 2550 hit 84 MPH on a smooth flat (new blacktop surface) road in Florida at 14 above sea level, ambient temperature low 80s, and humidity probably near 90%. This speed was confirmed by my speedometer, my GPS, and a friends speedometer & GPS that was following me. Jack
DAMN KIDS!!! ;D ;D ;D
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Your absolutely right bob and I apologize for asking a question, I see several math errors and figures that couldn't possibly exist in the real world, I see variables that arn't addressed like timing, injector size, etc, I see where this is a test book example of a textbook and your all blindly accepting the information and nodding in approval. but I'll certainly back off and not ask any more questions,,except for the one I just asked, this all brings to mind a professor I once had who could run a program and extrapolate a projected answer to any question that was asked but had a margin of error that made any close miss a reasonably good shot. One question I have is that of the absolute certainty of several statements that a stock 8-71 couldn't attain a speed of 80 much less a speed of 85, this we all know to be untrue, all I'm saying is I see a lot of textbook theory and no indication of any real experiance or knowledge. But thats my failing and only mine. I apologize for not nodding in agreement or unison.
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Cody: Regretably, you know too little about what you are talking about to actually contribute to this discussion, or you read my text too sloppily!
When I said that my 8V71 could not attain 80 mph in stock form, I was saying that because my stock 8V71 was governed to 2100 rpm. With the combiantion of my 3.73 gearing, Allison tranny, and 478 rev/mile tires, to hit 80 my engine would need to EXCEED that 2100 rpm governor speed! To do 80 mph, it would need to turn at 2377 rpm, and to do 85 mph, it would need to do 2526 rpm. In addition, the Caterpillar booklet, which I regard as much more credible than you, says very clearly that a coach roughly similar to mine needs more than 272 hp to hit 85 mph, if you add up the road resistance, air resistance, and fan power. I thought I made this very clear to anyone who is actually READING the text versus foaming at the mouth because someone is doing something differently than you like to do it. :)
As for credentials, go take a long hike on a short pier. What are YOUR credentials, wiseguy? I don't owe you any credentials, just as you owe me none. If you like what I write, believe that my writing reflects some knowledge and/or ability, and believe I am credible, continue to read my postings. If you dislike what I write, or think I am not credible, just don't read my postings. It's that simple. But, get out of the way when intelligent people ask intelligent questions and look for better answers to old questions. If that bothers you, just stay off this thread. Then, neither of us has to listen to each other! :)
Jim G
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By your own statement you found yourself going 80 to 85, I have nothing more to say. Your right I know nothing, I openly admit that, you should too. I'm terribly sorry I offended or scared you, check your own math when you have time or read what you posted, and just where did you find diesel that weighs in at 71.5 pounds per gallon. I'm gone now, enjoy your thread, but even an unintellegent person like me can use a calculator. sorry if I bothered you.
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Jim G,
Thanks for the fresh approach to problem solving. It's appreciated and stimulates the brain! I know where you're coming from. Having been around racing and engines most of my younger life I enjoy looking at performance from a theoretical as well as an empirical standpoint. Keep up the good work.
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Jim -
Hmmmm. . .
Reverse engineer the numbers again with a coach weighing 20,633 lbs, 471 rev/mi tires, 4.125:1 final drive, 0.808 bevel gear ratio, & the following gear ratios: 1st = 4.32:1, 2nd = 2.50:1, 3rd = 1.50:1 and 4th 1.00:1. Stock 8V71 w/ N60 injectors.
I'm curious.
Oh, and as a side note, looks like my "real world" fuel mileage figures that I shared with you in your other thread matched your modeling, eh?
FWIW & HTH. . .
;)
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RJ: This first early version of the model is not yet easy to quickly adapt to other buses and drivelines. To do that, I need to replace hard numbers in the model with alterable variables and tabular lookups. For eample, right now the only power curve in the model is the table for my own bus, and the only road and air resistance data is that from the Caterpillar booklet for a coach of not only my weight (about 34,000 lb) but also for only a limited rnage of road speeds (55 to 85 mph).
It takes many hours of work to build even a limited model like this one, and many, many more to make it capable of accepting other vehicles and a broader range of speeds. I also want to add the ability for it to automatically choose the best gear ratio for (a) cruising or (b) acceleration for any given speed, and to accept 4, 5, or 6 speed gearboxes. I also want to be able to model hills ranging from 1% to 6%, so that a user could compare performance on flat highways to that in hilly or mountainous areas.
Your request is a bit early! I will work on this model over time, but I have a high priority project that I am in the middle of - I am losing my house (I lost my job last fall and finding an new one in this economy has been a struggle), and have to concentrate FIRST on getting our possessions pared down to fit into the Eagle. I took some time to do this early rough model over the past couple of days because I LOVE doing this kind of stuff and I needed the break from the other somehwat depressing work!
Don't worry, I WILL take this a lot further and make it a lot more generically usable. I just need some time to do so. Once I have done that, it will be possible for me to model MANY people's buses with a LOT less time and effort being required for each.
I have corrected the typo that Cody was so sure proved I was stupid. I had misplaced the decimal point in my text, and had described the weight of diesel fuel as 71.5 pounds per gallon versus 7.15 pounds per gallon. The math within the model was of course correct all along, using the correct 7.15 pounds per gallon within the calculations (the results would have been VERY odd otherwise!).
I also apologize for the persistent and frequent transposition of letters as I type (e.g. letetrs versus letters). I continually have this problem, and these website forums do not have spell checkers built in like Microsoft Word does! :) I try to edit them out as I review my postings, but miss a few.
Jim G
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I'm sorry, but I quit reading when you said your 8V-71 had a supercharger.
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Len that is only one of the areas I found difficult to accept, Jim, I wish you well in your quest but more importantly I wish you better math, the weight of the diesel fuel was comical to me, nothing more than that, the math errors are a completely different matter, it appears people are blindly accepting your information as cast in stone and in time others will also double check them, thats all I had hoped for and I find that several have and have found the mistakes I did, regardless of my stupidity, I did pay close attention in college as many others here have also done, sometimes less time spend in front of a calculator and more time spent with a wench or steering wheel in your hand carrys some value too.
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I'm sorry, but I quit reading when you said your 8V-71 had a supercharger.
Len: EVERY 8V71 has a supercharger. Some people call it a blower, some call it a supercharger. Although a 2-stroke engine can certainly function without one (like most 2-stroke motorcycle engines used to), the 2-stroke Detroit Diesel as designed won't work without it. Its prupose is to create positive pressure in the intake system so that when each piston is low enough in its cylinder to expose the intake ports cut into the cylinder walls, the pressurized intake charge is forced into the cylinder and also helps to evacuate the exhaust gases still in the cylinder.
Models of the V71 series of engines that have a "T" in their designation (e.g. 8V71T) ALSO have a turbocharger, to force even more air into the intake system. Models with "TT" in their designaiton have TWO turbochargers.
Models that have "TA" or TTA" in their designaitons have aftercoolers as well as turbochargers, in order to cool the compressed intake charge (the process of compressing the intake charge heats it up, and hot air makes less power than cold air, so it is very beneficial to cool it back down as much as possible).
Where's the problem here???
Jim G
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I'm sorry, but I quit reading when you said your 8V-71 had a supercharger.
As far as I knew Len every 2 stroke diesel has a blower. Yours is different?
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A quote from DD,, There are NO superchargers on the 8V-71 engine. ALL 2 stroke series engines from DDA have blowers. These are either gear or shaft/gear driven. This includes the series 53,71,92,110,149. But what do they know, this is from one of their own service papers. I won't be responding to this thread anymore, I learned a long time ago not to pee into the wind.
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All right, first of all, I apologize, that was smarmy of me and not my style.
However, when someone refers to the blower on a DD two stroke as a supercharger, my perception is that they probably have never turned a wrench or gotten their hands dirty. It's just a question of semantics but DD refers to it as a blower or scavenger even though the 6-71 blower is often used as a supercharger on gas engines.
I slink away now.
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Len that is only one of the areas I found difficult to accept, Jim, I wish you well in your quest but more importantly I wish you better math, the weight of the diesel fuel was comical to me, nothing more than that, the math errors are a completely different matter, it appears people are blindly accepting your information as cast in stone and in time others will also double check them, thats all I had hoped for and I find that several have and have found the mistakes I did, regardless of my stupidity, I did pay close attention in college as many others here have also done, sometimes less time spend in front of a calculator and more time spent with a wench or steering wheel in your hand carrys some value too.
Cody, I thought you said you were "leaving". Is this your ghost, or do you simply love being crotchety?
If there are math errors in my model, I would not be offended if someone pointed them out, but rather would aprpeciate it, as I want as accurate a model as it is reasonable to build. As I pointed out in my text, there are big gaps in the available data in both literature and on The Web, and I did say I had to make some assumptions (one was how an 8V71 performs when revved past its factory governor speed), and I did point out exactly where I did make those kinds of assumptions. We are not planning a space flight here, so having ALL the data EXACT is not that critical, but obviously the more accurate it is, the more accurate the calculated results will be. Since my predicted results so closely match the actual results obtained (basically, "right on"), I suspect I am not very far off anywhere.
If you see specific errors, please do us all a favor and point them out. If you are correct, I'll correct the model.
Please do note that virtually everything in the model is from sources like Detroit Diesel itself or Caterpillar, so before you throw too many stones make sure you yourself are right. I think the engineers who designed and built the engines, and the well resourced companies they are part of, probably know more about them than either you or me. I'm simply presenting the information in a way that makes it easier to understand and to use in a practical way. :)
I agree with your comment that spending time with a "wench" (your spelling) is more fun than with a calculator. :)
Jim G
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I also apologize for the persistent and frequent transposition of letters as I type (e.g. letetrs versus letters). I continually have this problem, and these website forums do not have spell checkers built in like Microsoft Word does! :) I try to edit them out as I review my postings, but miss a few.
Jim G
Jim,
I have the smae probleme! I think it has smoething to do with my gettin' older?? LOL When you write a post look to the right of the box that you click on to post your message. There is a box that says Spell Check. A former moderator, who passed away last year, was always a stickler for propper spelling and grammar. Are you watching over us Richard? Jack
Errors intentionally left in this post
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:D
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All right, first of all, I apologize, that was smarmy of me and not my style.
However, when someone refers to the blower on a DD two stroke as a supercharger, my perception is that they probably have never turned a wrench or gotten their hands dirty. It's just a question of semantics but DD refers to it as a blower or scavenger even though the 6-71 blower is often used as a supercharger on gas engines.
I slink away now.
Len, please do NOT "slink away". I confess that the use of the term "sueprcharger" is a giveaway on my 42 years spent hotrodding cars, bikes, and pcikup trucks versus buses. All of us that have done that have got too used to calling the Roots type blowers "superchargers". They are indeed actually "blowers". The difference is sometimes subtle, but you are nevertheless correct on this fine point (and so is Cody therefore, despite his rudeness throughout this thread).
The actual technical definition of a supercharger is that it compresses the air INTERNALLY. A Roots type blower does not actually compress the air INTERNAL to itself. It instead pushes enough air into the intake tract to create pressurization THERE versus inside the blower housing. This is ebcause the Roots blower design was originally invented NOT to pressurize intake tarcts on engines, but rather to circulate fresh air into underground mine shafts. It was subsequently recognized as a great way to pressurize the intake tract of an engine. It is particularly attractive in an application like the Detroit Diesel 2-stroke engine where its combiantion of large volume and modest pressure is pretty ideal for a large displacement, slow revving engine.
Its design is also inherently "modular", just as the Detroit Diesel engine itself is. For the larger versions of the engines, simply make the blower larger. This is why these blowers come in a rnage of sizes (which the car hotrodders really appreciate!).
Most hotrodders don't care about this subtle distinction, as the end result is the same: a pressurized intake tract. But, you and Cody are correct in that I should have said "blower" versus "supercharger".
This terminology distinction has NO impact on the math.
Jim G
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Jim,
I have the smae probleme! I think it has smoething to do with my gettin' older?? LOL When you write a post look to the right of the box that you click on to post your message. There is a box that says Spell Check. A former moderator, who passed away last year, was always a stickler for propper spelling and grammar. Are you watching over us Richard? Jack
Errors intentionally left in this post
THank-you! I had not noticed that spell check capability. THAT is sooooo nice to ahve available. Now, I just need to try to remember to use it each time!
Jim G
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Justa FWIW N65 injectors are nice but without having the timing changed for those injectors you may not
be getting the max power N65 can afford you. You stated injector reciepts but did it include changing the timing?
The rest I'll leave to those
Have a nice day
Skip
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Justa FWIW N65 injectors are nice but without having the timing changed for those injectors you may not
be getting the max power N65 can afford you. You stated injector reciepts but did it include changing the timing?
The rest I'll leave to those
Have a nice day
Skip
Skip: Unfortunately, both of the invoices I received as part of the documentation package with the bus (a whole 18" thick box of documents!), while they listed parts used, including those injectors and other parts, did not specify what was done and what was not done. The text of the labor description in both cases included the phrases "replaced" and "tuned" and "set", but did not specifically state what all was done. I may be able to contact the former owner and ask him, as I have his name and a phone number that was good back in February when he traded the bus in on a Prevost.
I do understand what you are tallking about. The Detroit Diesel sp0ec sheets and injector timing sheet I received from others on this board talk about that. I simply have no way yet of knowing what was done and what was not. Even if I successfully connect woth the former owner (for whom I have 6 other questions so far!), he may or may not know, depending on how technical he himself is.
Jim G
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Jim,very interesting posts,but aren't ya beating a dead horse now with the numbers?It is very interesting to learn what went into the original engineering of the detroit's(never knew that before),but as you stated
" virtually everything in the model is from sources like Detroit Diesel itself or Caterpillar, I think the engineers who designed and built the engines, and the well resourced companies they are part of, probably know more about them than either you or me"
Sounds like you are trying to re invent the wheel here,the numbers have been crunched before .
Out here in the wild wild west,MPG's At least for me is a big pipe dream.
no matter where you travel you are going to have to tackle one grade after another,so MPG's are useless,Hp and torque are the name of the game on the table.
We have to work with the chips we got.
So,engineering all said and done ,this leaves us with the one most important thing left,Tuning.
Engineers have there place and there is always room for improvement .
But it is the guy with the hands on experience that will fine tune that dude to perform to the best of it's ability,by knowing what works and what doesn't.
What works on paper,does not always work in the real world,and takes a seasoned mechanic to make it all work.
Please don't think That I am prejudice against engineers,I'm not,most actually do pull out hand tools and roll up there sleeves and get dirty LOL ;).
I think we have quite a few talented people on this board,ones that have done the impossible with their engines .
So ,all that said and done ,my feeling is if I want to boost performance ,I'll be talking to the seasoned mechanic as opposed to an engineer,they will certainly know what does and doesn't work.
Nice numbers by the way(but we already knew that),and welcome to the madness,I think the bug has bitten you in places no one else has been bitten :D
So keep posting ,and we will all learn together ;),hell,I might even break out my calculator (still need to find out what the red and black leads with the clips are for though :D)and help confuse things even further ;D.chow!
Bike's huh?would like to hear about itNever mind that's for the OT's
Carry on.
Van 8)
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Bike's huh?would like to hear about itNever mind that's for the OT's
Van 8)
There's a LONG history there - too long for a posting. Some of the more interesting projects included:
- A ducati Monster S4 that was mostly carbon fiber and light alloy, incluyding even carbon fiber wheels, headlight nacelle, etc), that lost about 70 pounds over stock weight, and took 2nd place at a bike show
- A Honda CBX 6-cylinder that I rescued from neglect but that handled like a tank despite my efforts (just way too heavy!)
- A Kenny Roberts replica Yamaha RZ350 2-stroke with computerized intake and exhaust timing. A 350 pound missile if ever there was one! I bought the original bike from a judge's daughter who used to street race guys on much larger bikes, and used her combination of light bike, light rider, and short duration races to humiliate the guys!
- A Chevrolet SSR retro pickup with Magnuson supercharger kit (technically a "blower" :) ) and other mods that got it to 575 crank hp, while remaining reliable and driveable enough for daily driver use (over 43,000 miles on it when I sold it, and not ever a glitch)
- an unfinished 1955 FIRST Edition (not 2nd Edition!) "Advance Design Series" Chevrolet pickup truck that got a 6.0 liter LQ9 engine recammed to about 450 crank hp, fiberglass leaf springs that cut the weight of the springs from 156 lb to 24 1/2 lb, and got to a TOTAL weight of 2975 pounds ready for the road! Unfinished because that's when I lost my job and had to start selling the truck off as parts :(
- The current "daily driver" (it's my ONLY car): 2009 Mustang GT with Roush supercharger kit (technically a "blower" :) ), Roush cold air intake, Roush exhaust, and Roush Stage 3 suspension. 475 crank hp, cornering better thn 1 G, and 22 mpg on the highway at 73 mph. My wife drives this every day and has no clue what happens when you floor it. The young punks at her workplace are all green with envy :) .
Yeah, I get pretty serious when I do a project.
Jim G
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You are right Jim,those are some impressive after market parts,and cost a bunch,But what I would do now is have your local Whizz Bang guru whisper into your engine's ear that sweet,sweet melody which makes them run oh so beautifully stout ,cause with out them,numbers are like cereal with milk,once digested it all ends up in the black tank anywho.Have a great bus nut day,gday
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JimG,
I think you are well appreciated here. "Some" of what Cody says has "some" merit from his perspective. I can't see where the vitriol is warranted and this situation saddens me a little. Cody has been around a long long while and has been of much service to many and is known to have his heart in the right place. Watching this from my distant posit it seems obvious that there is a clash of personality that cannot be easily explained or justified. I know I have fallen into the same mode as Cody and I most certainly have gotten the butt end on more occasions than I can count over the years. Please "bare" with him and all of us for that matter. You are appreciated and I hope you will continue in your current "vane". Please
overlook this episode and start fresh.
Sorry to hear of your current dilemma with work and all. Truly sad stuff is happening all over the nation. That doesn't cheer you, I understand, but, it doesn't seem that it is the fault of the people that are being damaged. Cody has recently suffered a near tragedy concerning his wife's health. He nearly lost her and he received an outpouring of sympathy. Our sincere concern was backed up with a collection to help him purchase an oxygen machine to make her more mobile and lessen some of the burden. No doubt he was patient, compassionate and generous in his own right even before his most recent hardships tempered him even further. Please be patient with us and know that we are appreciative of the time and energy you have expended.
HTH
John
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I am sure there is a Detroit Diesel forum available for this type of information and splitting of hairs
Jim you are probably a great guy with a lot of knowledge however the way you are writing some of your posts seems to indicate that all of us that were here before you came on the board had just fallen off of a city bus and are stupid, oh and we don't know anything regarding our beloved 2 strokes.
the info you are trying to present is not the problem the way it is being offered is !
just a observation from this end
God Bless and have a great day good luck Amen
Chris
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Van,
Your points are well made and taken. Engineers were the bane of my life for many years. Still, I have met some positively sterling men that were engineers to the bone. One was a gentleman named William Guion from San Antonio and worked at South West Research Institute. Had a Dr. in electrical engineering. Unlike any I have known, William (never call him Bill) could modulate his communication to any level or lack of technical understanding/background you could imagine. He spoke to a group of brainiac research engineers for thirty min and I understood nary a word but he sure taught me a lot and also did so for everyone we put before him. Now William had a Shelby Cobra in his 4 car garage. You know, the original. The one with the aluminum body. He built/blueprinted the engine himself, I understand, but I can't swear to it, not having been there. I do know that he had a wall in his garage that was made by "SUN SYSTEMS", literally, and he knew how to use it. He was so generous that he took a few sailors (USN) home over the weekend to resolve a problem they were having with their van that developed on the drive from Wash., DC. Truly, a unique man. Every ME I have ever met had grease under his nails. Still, I know where you are coming from.....in spades.
Three of William's fellow engineers said to me with wide eyes and the hint of terror in their voices " Don't go for a ride in that thing with him, John. Don't do it!" Sooooooo he built it, knew it and used it. Rare bird.
Thanks,
John
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Hi Cris,I think this is a link to the DD yahoo group
http://autos.groups.yahoo.com/group/DetroitDiesel/
if not sorry. :)
these guys are pretty wild ,some very interesting(and strange)things going on there. :o
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John,sounds like a rare bird indeed,he has my respect ,as do a few others of his caliber,also from Texas .Have a safe Memorial Day Weekend,and don't forget to thank a vet,soldier and remember those that gave so much .Van :)
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http://www.google.com/search?q=Jim+Gnitecki&rls=com.microsoft:en-us&ie=UTF-8&oe=UTF-8&startIndex=&startPage=1 Some interesting information has come to light that may explain the sudden interest in all things mechanical, it seems that mr jim goes from board to board, dazzles them with tidbits of information then is willing to sell them the necessary missing pieces to complete the model, he does this as a business not as a friend to us poor trusting 2 stroke busnuts, if you google the guy you can find that he has infiltrated almost every board that there is, this link is only one that was sent to me, I have since found many others. I apologize to any that I may have offended either in this thread or in the next one but after spending half my life in prison it's not hard to spot a con or a game, I'm not sure which it is but something just isn't right here.
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Another shiny minnow,you suppose ? LOL!
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Did either of you guys actually follow any of those links? I did and found nothing but praise for the report that Jim issues and as far as I can tell its one specialized report for one specific situation. I don't know what particular burr is up your butt Cody but its not pleasant - its demeaning to you and to this forum. Take your vendetta private please. Some of us are learning from this thread and so far all it has cost us is time. If that changes we'll make our own decisions.
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You are right Jim,those are some impressive after market parts,and cost a bunch,But what I would do now is have your local Whizz Bang guru whisper into your engine's ear that sweet,sweet melody which makes them run oh so beautifully stout ,cause with out them,numbers are like cereal with milk,once digested it all ends up in the black tank anywho.Have a great bus nut day,gday
When I get re-employed, I will want to find a tuner to do his magic on the engine, but right now, it's sort of mostly financial survival time! You have to play the hand that you are dealt . . . :)
Jim G
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JimG,
I think you are well appreciated here. "Some" of what Cody says has "some" merit from his perspective. I can't see where the vitriol is warranted and this situation saddens me a little. Cody has been around a long long while and has been of much service to many and is known to have his heart in the right place. Watching this from my distant posit it seems obvious that there is a clash of personality that cannot be easily explained or justified. I know I have fallen into the same mode as Cody and I most certainly have gotten the butt end on more occasions than I can count over the years. Please "bare" with him and all of us for that matter. You are appreciated and I hope you will continue in your current "vane". Please
overlook this episode and start fresh.
Sorry to hear of your current dilemma with work and all. Truly sad stuff is happening all over the nation. That doesn't cheer you, I understand, but, it doesn't seem that it is the fault of the people that are being damaged. Cody has recently suffered a near tragedy concerning his wife's health. He nearly lost her and he received an outpouring of sympathy. Our sincere concern was backed up with a collection to help him purchase an oxygen machine to make her more mobile and lessen some of the burden. No doubt he was patient, compassionate and generous in his own right even before his most recent hardships tempered him even further. Please be patient with us and know that we are appreciative of the time and energy you have expended.
HTH
John
John: Thanks for sharing that information - all of it. It helps me understand better what might be going on. My wife too has had very serious health issues the last few months. She has been admitted to the hospital emergency room twice. She and I are both of strong faith and regard that as just another attempt by The Enemy to try to disocurage her, as she is in charge of the prayer ministry at our church. I don't regard the current unemployment as a stress. It is a cleansing that enables us to shed and simplify. That's a good thing.
Jim G
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Understand,on the line myself,on the other hand check Don Fairchild out @
http://www.cctskit.com/
One of the many well versed DD folks on board.good luck
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I am sure there is a Detroit Diesel forum available for this type of information and splitting of hairs
Jim you are probably a great guy with a lot of knowledge however the way you are writing some of your posts seems to indicate that all of us that were here before you came on the board had just fallen off of a city bus and are stupid, oh and we don't know anything regarding our beloved 2 strokes.
the info you are trying to present is not the problem the way it is being offered is !
just a observation from this end
God Bless and have a great day good luck Amen
Chris
Sorry if I unintentionally came across wrong in some way. I was not intending to say anyone is right or wrong or smart or dumb. I was simply trying to say exactly what I said in my opening remarks: I wanted to build a model that would help me answer some questions I had about what would likely happen under certain scenarios (different mph speeds, different gearing, etc). I figured by publishing it here I could (a) get helpful inputs from other members and (b) maybe help other members answer some of the questions they might have that are similar to mine. No other agendas.
Jim G
p.s. the spell check works great when I remember to use it, as I finally did this time.
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No vendetta bob, your old enough to make your own choices good or bad, read further, check information and follow the money, and I wish you well. I guess I gave credit where it wasn't due but it's not the first time I've done that. You can spend time on the different forums too and see the end result as well or we can just wait for it here really doesn't matter that much, for some interesting reading do a lein in texas.
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When I get re-employed, I will want to find a tuner to do his magic on the engine, but right now, it's sort of mostly financial survival time! You have to play the hand that you are dealt . . . :)
Jim G
There is a guy down here in Florida that you should talk to. He runs 2 antique tractors in the tractor pulls. The Oliver 77 Row Crop has a 2-53 Detroit that has the governor set at 3400. The Oliver 88 has a 3-53 Detroit and has the governor set at 3600. I do not know how much horsepower they are producing, but wherever you are in the park, you know when those tractors are pulling. It's a beautiful sound!! Jack
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Hi Cris,I think this is a link to the DD yahoo group
http://autos.groups.yahoo.com/group/DetroitDiesel/
if not sorry. :)
these guys are pretty wild ,some very interesting(and strange)things going on there. :o
Hey, THANK-YOU. That website does sound pretty interesting. here is the mission statement for it off the link page:
"This is a group for the exchange of info about older GM Detroit Diesel engines, the old two strokers, the 51, 53, 71, 92, 110 & 149 series engines and not so much the newer stuff they are building today. Any Detroit Diesel related topic is welcome."
I need to spend some time there. :)
Jim G
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http://www.google.com/search?q=Jim+Gnitecki&rls=com.microsoft:en-us&ie=UTF-8&oe=UTF-8&startIndex=&startPage=1 Some interesting information has come to light that may explain the sudden interest in all things mechanical, it seems that mr jim goes from board to board, dazzles them with tidbits of information then is willing to sell them the necessary missing pieces to complete the model, he does this as a business not as a friend to us poor trusting 2 stroke busnuts, if you google the guy you can find that he has infiltrated almost every board that there is, this link is only one that was sent to me, I have since found many others. I apologize to any that I may have offended either in this thread or in the next one but after spending half my life in prison it's not hard to spot a con or a game, I'm not sure which it is but something just isn't right here.
???
I have at times been, or continue to be, a member of the following boards (any maybe one or two I have forgotten about:
www.ssrfanatic.com (the forum for Chevrolet SSR owners)
www.fnsweet.com (the forum for Roush owners)
A Ducati motorcycle board whose name I have forgotten (5 years ago or so)
www.s2k.com ( a forum for Honda S2000 owners, because I owned one for a while)
The only things I have ever sold to any forum members are:
- a 320 page e-book titled "The SSR Experience" which members of the www.ssrfanatic.com board (owners of Chevrolet SSR retro pickups) ASKED me to write about 4 years ago, and subsequently bought from me in large enough numbers to qualify as a commercial success because it is GOOD and told owners how to fix all the issues that the vehicle came with from the factory (because it was too low volume for GM to get properly qualified).
- a customized gearing service (cost $29) for Ducati motorcycle owners that figured out for each rider what gearing would work best for his or her circumstances and intended usage. I offered the service because I did it free for a few people and before I knew it, EVERYONE wanted it done for them. I charged the $29 to try to limit the work to people who really VALUED it. Since each customized report took me roughly 2 hours to produce I made a whopping $14.50 per hour off those "poor owners". I don't see that as any way wrong.
I don't think this qualifies as "infiltrating every board you can think of". Nor does it qualify for your rude posting that somehow makes it sound liek I am trying to be some sort of shyster.
I think it is also pretty dispicable that you have tried to present what I have done as somehow crooked or immoral. You have deliberately tried to slander me, and there is no jusitifcaiton for that. Have I tried to sell you anything? Have I tried to deceive anyone? People like you make me sick, Cody. You are evidently so insecure that you cannot stand to see anyone else do something good and get a few pats on the back for doing it. What are you afraid of. That someone else who is better than you might be making an apeparance on the board that you somehow view as your personal turf, to be used for your glory?
You owe me an apology.
And, I think the moderator of this board should INSIST that you provide one. Saying someone is wrong, or saying you disagree with someone, is one thing. But trying to make it sound like someone is some sort of crook or deceiver when that is clearly not the case is slanderous.
Furthermore, you have have said several times during this thread that you are leaving. Please do us all a favor and stop TALKING about leaving and actually DO it. The World would be a better place.
Jim G
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Understand,on the line myself,on the other hand check Don Fairchild out @
http://www.cctskit.com/
One of the many well versed DD folks on board.good luck
Van: Thank-you for this link. I would never have found it without the pointer to it. It looks pretty interesting. How did you come to learn of it? Are any of this forum's memebrs involved with that program?
Jim G
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There is a guy down here in Florida that you should talk to. He runs 2 antique tractors in the tractor pulls. The Oliver 77 Row Crop has a 2-53 Detroit that has the governor set at 3400. The Oliver 88 has a 3-53 Detroit and has the governor set at 3600. I do not know how much horsepower they are producing, but wherever you are in the park, you know when those tractors are pulling. It's a beautiful sound!! Jack
Jack: That kind of rpm is impressive from an engine with the piston stroke and design history of a DD. That does indeed have to be a beautiful sound to experience. I really appreciate these pointers to interesting sources of information, guys. The more you learn, the more fascinating it becomes.
Jim G
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Bob, I have to agree with Cody on this one sorry but something ain't right in Denmark as they say
Chris
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There is a guy down here in Florida that you should talk to. He runs 2 antique tractors in the tractor pulls. The Oliver 77 Row Crop has a 2-53 Detroit that has the governor set at 3400. The Oliver 88 has a 3-53 Detroit and has the governor set at 3600. I do not know how much horsepower they are producing, but wherever you are in the park, you know when those tractors are pulling. It's a beautiful sound!! Jack
There was a guy in Saskatoon that used to run a modified Allis in the tractor pulls. I think he was related to the Summachs that owned Flexi-Coil but my memory might be playing tricks on me. I can't remember whether it turned 9,000 or 11,000 RPM but it was a pretty sweet sound too. Smoked white smoke like a steam engine until it got spooled up but it was fun to watch. I think it was the same one that still had the torque converter in it - they ran dry ice in the TC to keep it cool.
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I hear that Sam Walker is an innocent victim of others with an ax to grind, a lein is easy to run. There will be no apology in regards to that from me, I've read several reports both state and individual, and it's only slander if it's untrue. But your right I am interfering with free enterprise here, for that I'll apologize.
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Reagan said it best,trust but verify.but in the mean time,sharing of info and like mindedness in the hobby should be first and fore most on our minds.
so in the interest of the forumI'll share this (woopie I finally got something to share ;D)http://autos.groups.yahoo.com/group/DetroitDiesel/files/Detroit%20Diesel%202%20Stroke%20Specs/
Jim, these might be the charts you were looking for ,Idunno,maybe?
Can't say if any one from the board is a member or not,the motor heads will ,I'm sure ,I am a not so active but that might change.lotta new stuff posted since last I was there.Good luck
"Give peace a chance"
John Lennon
a smart man(saw it in a movie ;D)
If not, then we'll nuke em'
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http://autos.groups.yahoo.com/group/DetroitDiesel/files/Detroit%20Diesel%202%20Stroke%20Specs/
Jim, these might be the charts you were looking for ,Idunno,maybe?
Can't say if any one from the board is a member or not,the motor heads will ,I'm sure ,I am a not so active but that might change.lotta new stuff posted since last I was there.Good luck
Thank-you, Van. Via your link, I joined that group to see what it is all about.
Jim G
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Bob, I have to agree with Cody on this one sorry but something ain't right in Denmark as they say
Chris
Chris: So you are prepared to let an unscrupulous man slander an inncoent one? Is this the kind of group I am finding myself associating with? If so, I'll probably want to leave pretty quickly.
I realzie that would feed and reward Cody's dispicable behavior, but hey, I don't want to be around people who believe a liar.
Jim G
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I've read several reports both state and individual, and it's only slander if it's untrue.
WHAT "reports both state and individual"?
You are accusing me of doing somehting wrong. Put up the evidence or take your lies elsewhere.
Jim G
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I realzie that would feed and reward Cody's dispicable behavior, but hey, I don't want to be around people who believe a liar.
Jim G
Jim,
No flaming is allowed on this BB. From what I am reading, Cody has stated his opinion and posted some links to other sites, but he has not resorted to name calling. I see no placed that he lied, only stated his opinion. Your friendly moderator.
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I realzie that would feed and reward Cody's dispicable behavior, but hey, I don't want to be around people who believe a liar.
Jim G
Jim,
No flaming is allowed on this BB. From what I am reading, Cody has stated his opinion and posted some links to other sites, but he has not resorted to name calling. I see no placed that he lied, only stated his opinion. Your friendly moderator.
Cody did much more than state an opinion. He basically implied, without presenting even a shred of proof (becaue none exists because I have done nothing illegal or immoral) that I am somehow doing something illegal or immoral elsewhere. If what Cody did is acceptable on this board, and the local "law" doesn't want to do anything about it, then God bless you guys, but I am out of here. Life is too short to spend it around bullies like Cody, in communities where they are not held accountable. Sooner or later the other good guys will recognize that.
Jim G
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This is really sad. A new guy comes on-board and just because he approaches a problem from an engineering perspective he is ridiculed.
I have Googled Jim Gnitecki and could only come up with praises for his work on other auto/motorcycle boards, etc. He certainly doesn't try to hide anything. He even uses his real name, a real email and a real phone number.
What gives? What is the deal? Why is he being persecuted?
I don't know Jim, but I haven't seen what he has done wrong.
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This is really sad. A new guy comes on-board and just because he approaches a problem from an engineering perspective he is ridiculed.
I have Googled Jim Gnitecki and could only come up with praises for his work on other auto/motorcycle boards, etc. He certainly doesn't try to hide anything. He even uses his real name, a real email and a real phone number.
What gives? What is the deal? Why is he being persecuted?
I don't know Jim, but I haven't seen what he has done wrong.
Yeah , What gives here!
IF Jim has done or said something somewhere else.....say what it is!
But less some proof or fact.....This is totally unfair........and unwarranted.
I don't know Jim from Adam, but something doesn't sound right to me in these attacks of his posts.
Cody, if you know someting...SAY IT....quit this beating around the bush...
Enough of this the math or something is wrong, state WHAT is wrong (exactly and in detail) or back off.
I have NO dog in this fight, but I am missing something here.
Cliff
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It appears to me that we are seeing the new guy get beat up by the old guys who don't like new ideas. What is particularly distressing is that our moderators seem more influenced by personal friendship than even handed moderation. That is really disappointing and may explain why more lurkers don't become posters.
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Amen, Cliff and Bobofthenorth.
I can't figure it out.
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I gotta throw in a couple cents here. I read only part of Jim's first posting. It was going into far more detail than I could find useful now. However, it is one of those postings that I would mentally note is available in archives should I ever want it. I personally do not care if he sometimes hires out his skills. There are several on this board that do that, and I think we can all agree, that we are happy to have them as resources should the need arise. It is certainly true that engineering analysis can be carried to such a degree that it is pointless. Also, that specific problems are best handled hands on. But so what?
I think that Jim's posts had interesting information even if I am not in need of it at this time. I certainly did not see any snake oil for sale yet. The hostility and accusations were just unnecessary and do a huge disservice to all, including the prosecutors. Let's at least give someone a chance to screw up before being accused of something.
Jim,
If you are reading this, although I can understand your anger, it is out of line to call upon the moderators to publicly sanction someone and command an apology. That is where I must disagree with your reaction.
Cody,
I too have corrections experience. I realize that in that situation one must be watchful for games and scams, and that it is normal to develop a suspicious nature. I usually found it better to let people talk without me putting much effort into sorting the real from the false until they asked for something. There was just too much information to objectively sift through. Some played it safe by adopting the maxim, "If their lips are moving, they're lying," which was accurate most, but not all, of the time. As far as I was concerned, if they didn't try to get anything, it was just harmless talk. If there was something wrong, it would show itself soon enough. In short, lighten up.
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Jim,
I've looked at your original post & a couple of things bother me. Why are you content with the drag coefficient, it seems that it is far from known exactly enough to depend on. Since you have observed 80+ mph in your bus, you know the governed speed is above 2100. No engine horsepower data for either the stock bus engine or the "318" at speeds above 2100 is published. Simply extrapolating the curve for the stock engine shows it'll produce a bit over 300 hp at 2250 and may well exceed 320 at 2500. 2500 is the rated speed for some 8V71 engines used as pumpers and many knowledgeable DD folks claim these engines can run 2700 or so with reasonable reliability. We simply do NOT have enough data to get a reasonable model! There is also a wide variation in fuel usage due to how well the injectors match throughout their range of operation. Many of us have observed significant (some close to 20%) fuel economy improvement with well matched injectors. If you want to model fuel economy vs speed, gather some data. The first problem is getting accurate measurements of fuel used. My digital fuel gauge helps. Next run the same course under similar conditions (temp humidity etc.) at several selected constant speeds. For most of us it's just too much trouble. We'll drive at a comfortable speed and plan on a conservative (high) fuel use rate and be glad we did a bit better. I drive between 60 and 65 and get 8 MPG towing my minivan or 65 to 70 without towing an get 8.5MPG.
Regards
Jerry 4107 1120
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Jim,
just be glad you weren't challenging someones claims that a car can run on nothing but water, you'd better have thick skin if you're gonna do that. :o
We won't even think about questioning any of the problems concerning biodiesel or other 'alternative' fuel systems. ;)
Regarding your spread sheet, I have too much A.D.D. & too many distractions (& not enough time) to get thru it . . . yet . . . . ;D
As for me, I don't worry about the bullies until they show up at my door.
I'm not loosing sleep as long as 'they' stay on the internet, OR continue with excuses like; they aren't welcome, can't make the trip, were threatened anonymously, etc.
Well, you get the idea . . . . ;)
BTW, having personal problems is still no excuse for bad behaviour. It is not productive & merely creates more opportunity for fools to expose themselves.
To try to rationalize a poor choice by blaming other problems is denying the true cause & not helping you or anyone else to be a better person.
Does calling oneself a martyr make one a true martyr?
We all have our crosses to bear.
As for me, sometimes I can be a real first rate @$$hole. . . . but, usually I'm just second rate. ;D
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Cody has stated that in hindsight he might of handled the situation differently. But at no time did he make excuses or blame it on his personal challenges. That was another poster stating their take on it.
I would also point out this excerpt. When Cody pointed out flaws in Jim's statements/calculations and asked what his background was, this was Jim's response to him:
Cody: Regretably, you know too little about what you are talking about to actually contribute to this discussion, or you read my text too sloppily! ...
... As for credentials, go take a long hike on a short pier. What are YOUR credentials, wiseguy? I don't owe you any credentials, just as you owe me none. If you like what I write, believe that my writing reflects some knowledge and/or ability, and believe I am credible, continue to read my postings. If you dislike what I write, or think I am not credible, just don't read my postings. It's that simple. But, get out of the way when intelligent people ask intelligent questions and look for better answers to old questions. If that bothers you, just stay off this thread. Then, neither of us has to listen to each other! :)
Jim G
That is pretty much where "bad behavior" started in this thread. Frankly, Cody responded alot more calmly than I have seen others in this forum respond to much lesser slams.
What came later would have been better handled through the moderating team, but was still more civil than some of the exchanges that have taken place here.
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Hey guys, I think the horse is already dead!
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I have taken the time to read thru this crap and I personally must say if I was someone new coming to this site and read the accusations I would have high tailed it out of dodge and quick!
I have met Jim G in person and from first words spoken I knew him to be a really intelligent fellow even though his choice of bus was an Eagle! That in itself should prove he isn't a saint! A pretty straight forward guy though and if he knows something and can provide a service and make money doing it then what makes him any different than you or me? Were all guilty of doing very similar things at one time or another!
What happens on any other board should stay there. What problems one has should be handled via pm's or the moderators!
Just MY opinion on someone that is new to bussing and whom I have met in person!
--- Moderator Edit - Forum Civility Rules ---
I will always tell it like it is to you and anyone else! Everyone that knows me knows, they get no candy coating from me! No need to! So if you want to play games, ya'll play up there. Keep it off the board. Its not the place for it!
Ace
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OK folks. The OP of this thread seems to have left the building and as Lin quite well said:
I think the horse is already dead!
Given the direction it is heading, it is also locked.