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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: RickB on October 17, 2010, 05:42:02 PM
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Hey all,
Went camping with the family at the interstate park in taylors falls MN this weekend and after all this flip flopping about whether or not I need a repower I finally figured why this had been such a issue for me. Since the accident and even for a few times before that I had went on a number of relatively short trips and had found myself agreeing with my friends who tell me i'm nuts for wanting to get rid of my very healthy 8V71 (I can hear you laughing Gumpy) and then this weekend's trip of about 40 miles each way was just plain miserable I had a reasonable headwind but I'm telling you it wasn't just slow up these hills it felt like it was too close to asking for a major engine malfunction due to the lack of power up relatively short and not all that steep hills. So what had changed between the week before and this weekend?
The tow vehicle.
That's it in a nutshell...If I want to feel relatively happy with the performance and reliability of my bus I am not going to be able to stay with my motor without mods (turbo, bigger injectors) or a completely different motor OR I'm not going to be able to tow my car anymore. It is just too close to feeling like I'm pushing a horse that is incapable of doing what I ask of it without major risk to it's well being.
With that in mind, all you 8V71 repower freaks out there, have you made the same connection.
I bought an awesome bus and then I added a tow hitch to it and that's when I became unhappy with it's performance.
That's it in a nutshell I guess. BTW the park and the time with my family was just too good for words.
I really am a happy camper.
Thanks
RB
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I know the feeling..advice go big 4 stroke and go for better fuel mileage at same time. PS I pulled 8000lb with my 8V92 once and couldn't tell the differance from pulling the HHR..In the 89 prevost.
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I agree. Hooking up the toad changes everything. You've got a big loss of power and maneuverability, adds greatly to your length, and not being able to back up means you are partially crippled. If I could avoid it, I would. If you ever find an inflatable car that could roll up and fit in a bay, let me know.
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"That's it in a nutshell I guess. BTW the park and the time with my family was just too good for words.
I really am a happy camper."
Rick,
Isn't that what it's all about. get your self one (or two or three)of those little scooters that you see running around everywhere. :)
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Pulled out the 8v-71 and installed a 8v-92 445 hp. just love it. Set the cruse and let her go.
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I know the feeling!! Two wks ago to Gatlinburg, I40. Can't get speed down hill for traffic, then 35-40 uphill with horns and fingers galore!! Yep, the 8-71 sound sweet runs great. It has no a** at all with a 16' trailer with bikes etc. Goin series 60 with world!! Got brakes, cruise, and better mileage!!
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Sorry, not wanting to hi-jack.
busnut104, did you notice any difference in fuel economy???
Greg
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You guys are only kidding yourself if you think a 12.1 8v92 won't hang with a 12.7 series 60 and get just as good of fuel mileage and torque,stick with your 8v92 idea Rick no re gearing and all the electronic BS to worry with
Pull into a DD dealer and it will cost you 1000 bucks for a bad 50 dollar sensor I know this for a fact I am looking a bill from Stewart and Stevenson that I just wrote a check for to mail Monday
good luck
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A good running 71 might be alright but I had overheating issues and was told that it was time for a rebuild.
I had an L10 put in -- I have had to make a couple of changes since the repower --- It is fun to drive now -- I didn't add a lot of HP but I have no electronics to worry about and I have no heating issues
I notice the toad when I am going downhill in the mountains on the two lane roads -- the toad has brake assist and I have to use the brakes for it to kick in
If you have a healthy 71 and no heat issues you may be able to do something to keep you happy and not make major changes.
And yes the gearing can be an issue
Just my two cents
YMMV
Melbo
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I have a 8v92 now 5 mpg..if I can get same power from 60 series and get over 7 that's a lot of fuel..I hear claims that the 8V92 can be tuned to get mpg but its past me and I am of the impression that I will not have to do anything to the 60 to get it to preform..S o yes I'm sure the experts can do it but at what cost..Guess I'm just dumb so will take the easy way out with guidance from others.. I'm hoping for over seven so Rick it's your decision.I weight 36,100 lbs plus 3000 lb hhr 5 mpg at 70mph. healthy discussion those who say they can do it should tell the rest of us how. bob
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Bob, no one is calling you dumb your XLE came with 60 series why change we are talking about a repower here big bucks.
With your setup you may get 7 mpg that is about what Jim gets on his 40 ft Eagle with a 60 series.
I know Hemphill Bros. have the H-45 with series 60 egr engines 515 hp and he tells me 4.8 to 5.6 mph tops.
Now I will tell you what dumb is a friend let the same guy that installed Melbo's engine into pulling a good 8v92 12.1 L and installing a L10 in his Eagle went from 450 hp down to 300 hp sad part he paid 10 grand labor plus the engine and parts
L10's are a good engine but on power they are not any better than a 8v71 or a 6v92.
I could never get the 9.5 mpg like Don on his 8v92 because of gearing but 7 to 7.5 with generator time at 70mph was never a problem give a 8v92 the right air to fuel and it will carry the mail as cheap on fuel as any engine on the road in it class and with a MUI engine no need to carry a Pro-Link in your pocket
good luck
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I have a 6V92 in my iggle and it doesn't seem to know if I'm pulling my full sized dodge ram 1500 4x4 or not and that truck is heavy, I don't seem to notice any power loss with the truck behind and the fuel usage seems to be the same either way, what am I doing wrong.
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Well we have a 8v92 and when I first bought the monster I was leaving phoenix and was pulling sunset point with car on a dolly. Now never having drivin a 92 before I thought to my self (boy did I make a mistake) what a gutless turd. Then four years later and a few changes , Like bigger air cleaner I mean twice as big as what was on there , I also installed an air throttle bingo life is good . Now I don;t get more than 6.5 mpg in this old girl and she weights 34,800 lbs and we pull a 5500 lb Tahoe. It is what it is fellas if you got the money do what ya gotta do but I'll stick with this ole 92 for sure ;D
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Hey Clifford I think I finally tracked down a TV7101 but I need all the stuff to put it on. Intake manifold (and I'm pretty sure the 8v92 intake/turbo mount has a different bolt pattern) I need the y pipe and all the plumbing. Also where am I gonna get an oil supply for this thing? I guess I could y off at the rear mounted oil pressure gauge but that would mean I'm pushing oil from the bottom of the engine to the top any thoughts?
Also, will I lose my emergency shutdown flapper? That thing kind of reassures me but the 8v92's must have a shutdown system as well right. I'm thinking a fuel shutoff switch.
Here's my logic regarding the other posts. With a 9 unless you are a fabricating genius and have hundreds of hours to work on your bus the repower up to anything other than an 8v92 or a 6v92 from a 8V71 has far too many unforeseen consequences and they are all expensive. I will never drive my bus enough to make back the 15k it would cost me if I got a mpg or two better mileage ( I can't weld and Brian Diehl said from experience "take what you think it's gonna cost to do a 4 stroke repower in time and money and double it".) and I would have to do major mods to the length and height of my engine compartment to do it.
In reagrds to the earlier post about cooling, I have completely rebuilt my cooling system with the larger 8v92 radiaitors and feel I could add a turbo to my existing motor or an 8v92 without any cooling issues.
Robert as far as the mpg issue goes Lea and I have discussed this at length and we have come to the conclusion that this is our main family source of recreation and yes with fuel at 3 bucks a gallon it costs me 50 cents a mile but it still works out in my favor when I compare my brother in laws trips with his family to Disneyworld with airfare hotels food etc. I used to think that 7-9 mpg would radically change my world but when you're only putting on 5k a year it just doesn't make that big of a difference. Some of you folks that are fulltiming it would make a really big difference but that's just not our reality anymore. I had to quit thinking of my bus as a 401k like I would invest in it and it would make me money. No matter how we look at it, if we are not using our buses for commerce (and I know we are all good little boys and girls ;D ;D and wouldn't dream of making money in our buses), this is an outflow of money to more or less of a degree and not an inflow.
I am leaning towards Don's advice to put a lo boost turbo on, some bigger injectors sneak about 50-75 more hp out of my existing motor and if she blows up then I don't have to argue with the wife about a repower ;D. Pretty sneaky huh?
Moving forward one way or another.
I can't ake another hill wondering if my 8V71 is gonna put a rod through the crankcase in protest of what I keep asking it to do.
RB
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I too thought about re-powering UP to a 60 series for better mpg but after figuring in the cost of the engine, the misc items needed for the swap, it was going to be up there pretty good, and to me, that would be a lot of fuel money that I probably would NEVER get back in my lifetime!
A friend of mine just re-powered his neo-plan with a 60 series to the tune upwards in the 30k range and that is figuring in his old motor and trans in a trade. It took about 3 1/2 months working on it EVERY day! Sure it runs good, looks good and the only thing he will probably get better is pulling hills from the extra torque over the 92 series. As for fuel mileage compared to the 92, probably going to be close to the same or worse since he went up in hp by only 50 and he COULD have re-programmed his old engine to get that!
Mine runs good, runs cool, pulls the hills, and will run 80 easy, even pulling my stacker trailer for now, and IF anything ever was to happen to it, I MIGHT consider it, but until then, that money I would spend on the re-power, in this economy is staying with ME!
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According to the Cat RV performance guide, for a 34,000# vehicle, it takes about 46% more HP to travel at 70 mph vs 60 mph.
According to the fuel curve for a 8V92, it takes more fuel per HP at 2100 rpm than it does at 1800 rpm.
There just might be something to the rumor that driving habits influence mileage . . . . . :o
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Rick- I turbocharged my 8V-71N. I had brown tag N65's for 300hp @ 800lb/ft torque. The engine smoked above 5,000ft-which is easy to do on the west coast, and of course had less power. At sea level it was fine. But at altitude, was afraid of taking steep mountain passes. Decided to turbocharge the engine. Just had the engine overhauled a few thousand miles ago. So had an air to air intercooler custom made (my radiator is about 8" in from the side because my bus is a 102" wide). Took the bus to Don Fairchild in Bakersfield where he pulled the entire engine/transmission cradle (Vdrive). He first pulled one of the pistons to see what rings I had, and they were the tight transit bus rings (compared to the looser truck style) so turbocharging would work. Since I had the 18.7 to one pistons (compared to the 17 to one turbo pistons) we went with a 12.7 Series 60 waste gated turbocharger to keep the turbo boost down to 15psi. Don installed 9G75 injectors (375hp and 1125lb/ft torque), bypass valve on the blower, fuel modulator to keep the injectors from opening up until turbo boost was up, plumbed up everything. After that, had the radiator increased from a 5 row straight fin to a 6 row serpentine fin; changed the muffler, air cleaner, installed an auxiliary trans cooler with thermostatically controlled electric fan, and ultimately installed 15 misters on the radiator-of which I just recently drilled two of them out to 1/16"-which really flows some water now!
Needless to say, the difference in power is dramatic. Where driving to Las Vegas from L.A. with my car in tow, there used to be several spots where I had to down shift, now the only two places I have to down shift is the Cajon Pass and Baker Pass. I actually have passing power. I just made the bus much more enjoyable to drive. Don also had the transmission overhauled at the same time. Total cost with trans overhaul $17,000.00.
I would have just installed an 8V-92TA, but you can't mount the 8V-92TA on a V drive because of the big vibration dampner on the front of the engine. But-both Don and I like the 71 series better-mainly because of the dry cylinder liners. Detroit's last version of the 8V-71TA with 80 injectors was 400hp with 1200lb/ft torque. If you rebuild your engine to a turbo spec, this hp rating would be used. Good Luck, TomC
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Tom,
Great info thanks for the help. I am going to contact my local DD shop with my serial # to find out what my piston's compression ratio is and I believe the TV7101 at 1.39 is rated at 15 lbs of boostand the housing on the turbo I am buying is 1.29 which will be a bit lower boost. I am going to have a talk with Don and get a list of all the things I am going to need to do this and what injectors he would recommend I am betting he is going to recommend the 9G75's for my setup. Being that my motor is really strong and I have a documented rebuild 40k miles ago I am gonna run it and when and if it breaks in a major way I will do an out of frame on it. I am interested in how he did the bypass valve on yours and if he used a 8V71T intake manifold. Also, where did you guys find an oil suplly to the turbo? What is your mileage with it?
I have the larger radiators and the small pulley and I cannot get it to even remotely get hot with the current injectors.
Do you have any pictures of the intercooler? I would love to see your system. I am assuming that the NA blocks did not have the internal plumbing for a aftercooler or Don would have mounted one on yours rather than the air to air correct?
I found a surplus place that may have all the plumbing otherwise I'm going to have to find an old truck with a fairly intact intake and exhaust system for an 8v71T. There was a guy on ebay selling the whole intake/exhaust system a few months back and I am kicking myself for not buying them.
Thanks for your help Tom
RB
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Rick, there is a plug on the oil galley above the first place for the dip stick on the right side of the engine for the oil supply or you can drill and tap one on the front of the engine.
good luck
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Actually my block is an aftercooler block-but the stock aftercooler is almost a joke. My fuel mileage is about the same (4-6mpg depending on gen usage for A/C), but with the increase in performance, no smoking at altitude or power loss, I really don't care. Good Luck, TomC
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I fully understand the repower thing. Look in the back of "HUGGY" a 4104. Right now i can kill all the mosquitoes in a two mile area every time i pass. very few trucks can keep up as long as it is below 30 degrees outside and no hills.
Do real good on the hills till the temp guage gets to 200 then i panic. I have already bought two sets of heads.
Also the water cooled intercooler is at the same temperture as the water. so a charge air cooler is next. Just waiting
on my friend Don to come back east. I have plenty of spring water to help with the installation.
more smoke more power. just watch the tractor pulls
uncle ned
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I'm just tired of wiping the two skroke slobber off anything I pull behind the bus!!! At least the four stroke won't do that. But then I will have to worry about rust on the trailer tounge!!LOL
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Even though I have a four stroke Series 60, it still smokes pretty good on a hard climb. The exhaust on a Dina comes straight out the bumper and my trailer is completely black with soot. I tried the pressure washer on it and it is still black!
With my Series 60 I don't slow much on grades even with a 32 foot trailer weighing 5,000+ lbs back there. I do feel it when accelerating though. My mileage was only down a few tenths pulling a 20 foot and 32 foot trailer on a long trip.
I still wish I had a 400 HP or larger Series 60, but that ain't happening unless I strike it rich or this motor blows up.
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The tow vehicle.
You're supposed to release the emergency brake on the toad before driving off in the bus. :D
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Is that tha yeller thang on tha dash!!!
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The tow vehicle.
You're supposed to release the emergency brake on the toad before driving off in the bus. :D
Any of you who think I didn't think of this are wrong!! So I sent the wife back to check it for me :D
That may explain why we haven't seen her around the house lately!! LOL
Gumpster we need to get together soon and look at your vacation pix and solve the worlds problems. You and wifey available for dinner sometime soon on this side of the cities?
It would be good to see you my friend,
Rick
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I'll put my part of this post to bed..I selected the 60 series 430 hp &1400 rpm with Eaton 10 spd autoshift w/.75 overdrive because I did not have a engine for the salvage shell I am building..that being said I am running a 8V92 89 prevost home build now.what I have learned back off throttle to 1900 and it gained 8/10 mpg 68 mph..will consider using larger air cleaner or two because we still are using the 89..Don't know for sure when other will be done..wish there was a pill we could put in our tanks and give us more power and double fuel mileage. Family First..ours is a family orientated coach. Bob
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I'll go record now Bob betting you a cold one after you finish your conversion with 430 hp series 60 in the 45 foot XLE you will be looking for a way to get 500 hp from that engine in 6 months LOL
good luck
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Clifford got two new(to me)man to feed.. My cousin teaches diesel mechanics at local trade school..he is itching to play..Ha Ha with the detroit. Bob
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I had looked hard at an 8V-92 mech. engine in a cabover. Had a reliabuilt sticker and was very clean. Called DD tech and they where as much help as usual!! Had ser. no. and all still no help. Looks like that one is going into one of Kyles senicruisers. ( If he dosen't blow the budget and buy more busses!)!LOL The 60 is set at 470hp on cruise. Guess I'll leave it there. The drop box still makes me nervous. I am told it will handle it, but I know what it cost me to rebuild it!!! Don't want to pay for that one again!!
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Eric, the Eagle drop box will handle up to 2600 ft lbs of torque several Eagles are running 625hp with 2000 lbs of torque never have a dropbox problem, the ring gear and pinon is the problem you all ways lose those when trying to backup if not careful.
A good 8v92 will rip those also I have 2 here at the house to prove that.
With a DDEC you can program the start torque that is what I would do to save the ring gear you think drop boxes cost a lot to rebuild just wait lol
good luck
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I remember when Byron lost his in SC last year!! I think he has bought everyone he can get his hands on !!LOL