Air requirements

T

Todd W

Comp Diesel Sponsor
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Nov 18, 2006
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I am wanting 1000 hp without drugs. I have been reading in the diesel tech section on garretts website and have a few ?'s.

TurboByGarrett.com - Turbo Tech101

using their formula of 22:1 AFR and a BSFC of .38 i get that i would need 167 lbs of air for 1200 flywheel HP. I don't know how much flywheel HP i need for 1000 to the wheels so i guessed at 1200.

I believe i read a post by dieselfreak where he stated that a .32 to .36 BSFC is what is needed and this reduces the air needed to 140 lbs for .32 and 158 for .36

Also the 22:1 afr is more minimal smoke reducing this amount also cuts down on air needed.

So my question to compD is what AFR are people running, do we know what the bsfc is for a 12V, and how much air is needed for HP. I have read that 10HP per pound of air but that doesn't jive with what garrett is saying.
 
Wish I had the info at my disposal for you but I don't. I do believe that the ratio is 10hp per pound of BOOST, not pound of air moved.
 
I can tell you weve made 1250 hp at the crank with a charger that flows 120 lbs per min at 57 psi boost. we use fuel to help keep the cylinder cool so our air fuel ratio probably does not coincide with the formula
 
I can tell you weve made 1250 hp at the crank with a charger that flows 120 lbs per min at 57 psi boost. we use fuel to help keep the cylinder cool so our air fuel ratio probably does not coincide with the formula
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I am glad to see that 10 hp per pound of air has been done with a diesel. So now i have a pretty broad range. Based on what I have read at various places I figure that we can make between 7-10 hp per pound of air at the crank.


By chance was this 1250HP made with a 12V. What was your engine speed. I assume that you had some pretty sweet headwork to get all that air in at only 57 psi.

And how do you use fuel to keep the cylinder cool?
 
And how do you use fuel to keep the cylinder cool?[/QUOTE]

You give it lots of fuel to put the fire out. (eg. large injectors)
 
it was on a 12v and it had a decent cylinder head, though weve got much better ones now just waiting to be dyno tested.

It made peak power at 4100 and was still makeing good power above 5000 where we shut the run down.
 
You'll need 135-140lbs/min. on the compressor side. If you use a GT47 you'll need one of the larger turbine housings or a wastegate around it to keep DP low enough to make the power.
 
it was on a 12v and it had a decent cylinder head, though weve got much better ones now just waiting to be dyno tested.

It made peak power at 4100 and was still makeing good power above 5000 where we shut the run down.
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Very cool, do you mind me asking what timing you were running?

You'll need 135-140lbs/min. on the compressor side. If you use a GT47 you'll need one of the larger turbine housings or a wastegate around it to keep DP low enough to make the power.
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Great thank you, so around 7 to 7.5 HP per pound of air, is this flywheel or to the wheels?
Also this post brings up a question I have been thinking about for a bit. While it seems that large tubine A/R's are the way to go for all out power how much does one loose by going to an externally gated tight A/R for the sake of drivabilty/spoolup?
 
biggy238 said:
Wish I had the info at my disposal for you but I don't. I do believe that the ratio is 10hp per pound of BOOST, not pound of air moved.
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The rule of 10hp per pound of boost worked on an HX35. Not really even close on anything else.
 
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