Re: How does improving air flow effect charge air psi? - Saab Performance Bulletin Board - Saabnet.com
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Re: How does improving air flow effect charge air psi?
Posted by Dean (more from Dean) on Mon, 20 Oct 2003 16:23:57
In Reply to: How does improving air flow effect charge air psi?, JJ, Mon, 20 Oct 2003 14:51:39
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Your boost control boosts to a taget PSI. The actual charge air density is then a function of temperature. So to increase power you have to increase the pressure or lower the temperatures or both.
When you lower intake restrictions, the turbo is not working so hard, so the air out of the turbo is less hot. So the air mass flow will increase. And the turbine does not have to work so hard, so the wastegate will be a bit more open. So the turbine exhaust gas pressure is less. Notice that we have been talking about inputs. The lowered exhaust gas pressure translates directly into greater engine shaft HP. And this also lowers the residual gas in the CC which increase the amount of charge air and fuel that will get into the cylinders.
Temperature is really critical. If the open element filter is inside the engine bay, the temperatures are bad from the outset. A cold air intake would help greatly. This will also make the turbo compressor work better and improve rate of boost. A SMBC will also improve spool up. Boost lag with hot intake air can be nasty.
If you have a marginal octane situation, poor spray patterns from fouled injectors and CC deposits can make things worse. A bottle of Techron Cocentrate may help.
posted by 65.68.101...
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