Author Topic: Advantages of Turbo Blanket for Large Diesel Engines?  (Read 313 times)

Offline chessie4905

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Re: Advantages of Turbo Blanket for Large Diesel Engines?
« Reply #15 on: September 25, 2018, 02:31:23 PM »
There are outfits that coat piston tops to reflect heat.
GMC h8h 649#028 (4905)
Pennsylvania-central

Offline Beluga Bus

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Re: Advantages of Turbo Blanket for Large Diesel Engines?
« Reply #16 on: September 25, 2018, 03:05:33 PM »
oltrunt,
I was a thermodynamisist in a former life, and to answer your question you need to look at the ideal gas law, which says PV=nrT. If V, n, and r remain constant, then if you increase the temp T then the pressure in the system must also increase.
Matt
PG 2904
Long Beach, CA

Offline DoubleEagle

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Re: Advantages of Turbo Blanket for Large Diesel Engines?
« Reply #17 on: September 25, 2018, 03:09:17 PM »


LOL some of the things the military experiment with on the 2 strokes made absolutely no rhyme or reason.Walter those marine engine have almost the same PSI of boost as the highway engines
   

Is there greater volume involved? Something sure accounts for all the extra horsepower in the marine versions. The military 8V71T had 440 hp, and the marine versions were 600+ hp.
Walter
Dayton, Ohio
1975 Silvereagle Model 05, 8V71, 4 speed Spicer
1982 Eagle Model 10, 6V92, 5 speed Spicer
1984 Eagle Model 10, 6V92 w/Jacobs, Allison HT740

Offline Beluga Bus

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Re: Advantages of Turbo Blanket for Large Diesel Engines?
« Reply #18 on: September 25, 2018, 03:37:38 PM »
Double Eagle
A marine 8v71 has the same volume as any 8v71. If boost psi is the same, the difference in horsepower would come from at what rpm the peak torque is measured. Using the formula HP= (RPM X T) / 5252 if you raise where the peak torque is measured from 1600 rpm to 2400 rpm you would also raise the horsepower by 50%.
Matt
PG 2904
Long Beach, CA

Offline chessie4905

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Re: Advantages of Turbo Blanket for Large Diesel Engines?
« Reply #19 on: September 25, 2018, 04:52:14 PM »
Just like pickup truck diesel. Pour in more fuel, more horsepower, more heat. With unlimited ocean cool water, just pull out the heat.
GMC h8h 649#028 (4905)
Pennsylvania-central

Offline DoubleEagle

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Re: Advantages of Turbo Blanket for Large Diesel Engines?
« Reply #20 on: September 26, 2018, 06:49:26 AM »
Double Eagle
A marine 8v71 has the same volume as any 8v71. If boost psi is the same, the difference in horsepower would come from at what rpm the peak torque is measured. Using the formula HP= (RPM X T) / 5252 if you raise where the peak torque is measured from 1600 rpm to 2400 rpm you would also raise the horsepower by 50%.
Matt

True, but what about the injector size differences, and timing? What about the effect of twin turbo's, would the pressures be higher, or would the volume of air flow be increased at the same pressures as single turbo's? The military 8V71T's were rated at 440 hp @ 2300 rpm (or 405 hp @ 2300 rpm), that is still a bit shy of marine specs. There must be other differences such as cam profiles.
Walter
Dayton, Ohio
1975 Silvereagle Model 05, 8V71, 4 speed Spicer
1982 Eagle Model 10, 6V92, 5 speed Spicer
1984 Eagle Model 10, 6V92 w/Jacobs, Allison HT740

Offline chessie4905

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Re: Advantages of Turbo Blanket for Large Diesel Engines?
« Reply #21 on: September 26, 2018, 07:17:31 AM »
If you look, at least in the DDA tune up section for 8V-71's, depending on application, the boost specs and injector size are all over the map. Seems max speed is up to 2300. I recall one engine with boost pressure in the 40's. Clifford probably has more info than I have on this. Don't know if he has any on marine.
GMC h8h 649#028 (4905)
Pennsylvania-central

Offline Beluga Bus

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Re: Advantages of Turbo Blanket for Large Diesel Engines?
« Reply #22 on: September 26, 2018, 08:11:41 AM »
I would think injector size and timing along with unlimited cooling capacity would be how they got those numbers. Loosing 20% of your fuel economy in a boat makes little difference, it would be like going from 0.5 mpg to 0.4 mpg.
Matt
PG 2904
Long Beach, CA