Please Explain To Me How This Works
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From: Fallon NV, Bellingham WA, Angeles City PI
Please Explain To Me How This Works
1. whats the difference between 22 psi on stock turbo and 22 psi on a bigger turbo?, how is it making more power?
jk man. You got a good answer from Mitchubishi there.
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Its all about the Ideal Gas Law......PV=nRT
a larger turbo can flow more volume at the same pressure, therefore more molecules of air can be compressed and stuffed into the engine.
a larger turbo can flow more volume at the same pressure, therefore more molecules of air can be compressed and stuffed into the engine.
You should look more closely on dyno charts too. I know 99% don't think it's important and only look at peak #'s...
Left side of the chart - smaller turbo will make more tq/hp than a bigger one.
At higher rpm's though, the engine doesn't have to fight all that backpressure created by a smaller turbo, so it makes more power.
Left side of the chart - smaller turbo will make more tq/hp than a bigger one.
At higher rpm's though, the engine doesn't have to fight all that backpressure created by a smaller turbo, so it makes more power.
Think of it like this... which will give you more water?
22psi in a garden hose?
or
22psi in a fire hose?
As others have pointed out it's all about the amount of oxygen that can be stuffed into the motor to mix with the fuel to provide power. Even if you get more PSI going in, it is not a true measure of how much O2 you are actually putting in.
22psi in a garden hose?
or
22psi in a fire hose?
As others have pointed out it's all about the amount of oxygen that can be stuffed into the motor to mix with the fuel to provide power. Even if you get more PSI going in, it is not a true measure of how much O2 you are actually putting in.
^ that's not the right way to think about it. But even if you do think that way - 22 psi in a "garden hose" UICP form a big turbo is the same as 22 psi from a small turbo. You're not changing hoses here... 22 psi at manifold is just that. No matter which turbo you use to make that.
Temperature does matter though.
Backpressure matters
Speeds of the turbine and compressor matter
Efficiency at certain rpm's and flow (from flow charts) matter
Temperature does matter though.
Backpressure matters
Speeds of the turbine and compressor matter
Efficiency at certain rpm's and flow (from flow charts) matter
Last edited by mplspilot; Dec 26, 2007 at 12:33 PM.
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I've asked this same question here before.
Making power is all abou t helping the engine breath better. When you switch to a bigger turbo, which notmally also means a larger tubular manifold, you are greatly reducing exhaust back pressure. I believe this then allows exhauts gassed to escape the cylinders with greater velocity, which in turn aids the velocity of incoming air because there is overlap of exhaust and intake valve openings.
Net result is less exhaust backpressure = more power. This I believe is 95% of why a bigger turbo will make more power than a smaller one at same boost level.
One other effect I think, is exhaust back pressure also contributes to heat at the exhaust valves, this might effect detonation as well, and so you might be able to run more ignition advance as well I think.
I'm no expert but I think those are the main reasons. The cooler incoming charge, and the garden hose analogy are not so helpful.
Making power is all abou t helping the engine breath better. When you switch to a bigger turbo, which notmally also means a larger tubular manifold, you are greatly reducing exhaust back pressure. I believe this then allows exhauts gassed to escape the cylinders with greater velocity, which in turn aids the velocity of incoming air because there is overlap of exhaust and intake valve openings.
Net result is less exhaust backpressure = more power. This I believe is 95% of why a bigger turbo will make more power than a smaller one at same boost level.
One other effect I think, is exhaust back pressure also contributes to heat at the exhaust valves, this might effect detonation as well, and so you might be able to run more ignition advance as well I think.
I'm no expert but I think those are the main reasons. The cooler incoming charge, and the garden hose analogy are not so helpful.
