APS monster exhaust

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Sep 9, 2005 | 10:50 AM

#41

atlsupdawg#2

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From: ATL-What U Know About That???

Quote:

Originally Posted by Sharif@Forged

Both of you are mostly correct.

The idea is to have an exhuast system that creates zero back pressure, or as close to this as possible. Even on a turbo system, high back pressure will create massive trq down low, at the expense of heat, and power up top...not ideal...and boiderline dangerous.

An exhuast system that is complete open may not be ideal, as an exhuast system can help with exhuast gase scavenging, and can help draw the exhuast gases out of the combustion chamber. And a small amount of back pressure can increase low end trq. It is a very fine line.

That said...true dual 2.5 inch is generally optimal for about 10psi, and anything above that, I would be looking at a 3 inch true dual.

From what you stated above I believe this would be more of a header design issue than an exhaust. Short, or log headers coupled with a turbo would cause more back pressure; good for low end torque at the sacrafice of high end gains. Whereas a header with longer equal length primaries would cause less back pressure by allowing the valves to fully close before any exhaust gasses make it back to the motor. With that you sacrafice low end torque for high end gains.

Sep 9, 2005 | 03:35 PM

#42

Sharif@Forged

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From: Marietta, GA

Quote:

Originally Posted by theking

Sharif is the voice of reason(as usual) My car can overheat easily right now at 12psi with the borla td and test pipes. My torque number is higher than my hp number because of this.

You are correct!

And possibly not enough ignition timing advance. With a zero backpressure exhuast system, you can run much greater ignition timing advance towards redline.