How Much Boost Does It Take?
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Freshman User
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How Much Boost Does It Take?
No, Not to smoke a Honda. I was just wondering what the minimum boost level would be to maintain stockish power levels up hills or at altitude. I have always turned wrenches on gas motors, and boost was always just to make things faster. The stock NA IDI looses momentum up hills, and runs out of air I guess. Curiosity, 1, 2, 3 lbs at 500-550cfm. Any ideas?
Post Fiend
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From: Nutter Fort, WV
7.3 = 444 Cu. In.
444/2= 222 Cu In displacement per revolution.
3300 Max RPM x 222= 732,600 Cu. In. per minute
732,600/1728= 423.9583 Cu.Ft. displacement per minute with no boost.
Atmosheric pressure 14 PSI.
So to run 7 pounds of boost, 423.9583 x 1.5 = 635.937 CFM
Not exact figures, but close enough for government work.
7 PSI will make it a different truck.
444/2= 222 Cu In displacement per revolution.
3300 Max RPM x 222= 732,600 Cu. In. per minute
732,600/1728= 423.9583 Cu.Ft. displacement per minute with no boost.
Atmosheric pressure 14 PSI.
So to run 7 pounds of boost, 423.9583 x 1.5 = 635.937 CFM
Not exact figures, but close enough for government work.
7 PSI will make it a different truck.
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So, 1.5 bar or atmosphere would be equal to 7 psi at sea level, correct? Then a turbo or supercharger would have to be able to move @650 cfm at 7psi, to maintain intake pressure at 7psi at 3300 rpm. Up until recently I never gave much thought to how, just the why I was doing it. New truck, new ideas. By the way Dave, saw pics of your motor. Cool!
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Joined: Feb 2009
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From: Ortonville, MN
this kinda figures into this, although a bit of a threadjack, what is the over all purpose of an I/C on a diesel, reson i ask, is bc on a gasser, u do it to cool the charge so that u can run more boost without pre-det, but on a diesel the fuel isnt even a factor until its suppoed to fire, so the only guess i have is to lower EGTs...or is there something else
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An IC is to bring down the temp of the intake charge, making it a denser air charge. denser air means more air in the same space so you can burn more fuel/ make more power. At least that's what I was taught by some older guys.
Post Fiend
Joined: Nov 2003
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From: Nutter Fort, WV
Since the displacement in CFM at 3300 RPM is 423 CFM, and air pushed into the intake in excess of 423 CFM will start at creating pressure in the intake AKA boost.
When you compress air, the air temperature raises.
So with an intercooler, you lower the temp back down, prefferably back to what it was before it went in the air cleaner.
Even lower would be better on warm summer days.
Two things with cooler air or lower EGT and denser air in the cylinder, so it has the potential for a more complete burn of the fuel even at higher fuel rates.
I don't know what temp the air going in the cylinders is on my engine at 10 below zero, but I do wish I could have it that temp year round.
I can black out headlights during the summer if I want to, but at 10 below I can't even see any smoke at all when I stand on the loud pedal.
When you compress air, the air temperature raises.
So with an intercooler, you lower the temp back down, prefferably back to what it was before it went in the air cleaner.
Even lower would be better on warm summer days.
Two things with cooler air or lower EGT and denser air in the cylinder, so it has the potential for a more complete burn of the fuel even at higher fuel rates.
I don't know what temp the air going in the cylinders is on my engine at 10 below zero, but I do wish I could have it that temp year round.
I can black out headlights during the summer if I want to, but at 10 below I can't even see any smoke at all when I stand on the loud pedal.
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Post Fiend
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From: Faibanks Ak.
Dave yesterday morning it was 45 below and all of the pickups on the slope are diesel sitting there idling you could smell raw diesel and the exhaust pipes were wet with diesel.
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