Eh? You're saying that stock backpressure is HIGHER than most turbo chargers? In that case, exhaust will be pushed back into the cylinder, and pushing air/fuel mix back out of the intake valve, which as everyone knows, in a naturally aspirated car, has a slight vacuum.Stock backpressure is around 16 psi in a GSR
I think this is where some confusion is. I'm assuming zero backpressure = 1 atmo. If the pressure in the header is greater than 1 atmo (1 bar, 14.7 psi, whatever) then some of that force has to be pushing back on the valve. Law of fluid dynamics. If the exhaust is pushing back on the valve, then to me, that's back pressure.since the pressure inside the header is already much higher than on the intake side , even when there is zero backpressure.
None at all. You want a vacuum in your headers at all times to assist in exhaust scavenging.SPEED54 said:
Ummmm, so if i'm building a all motor high reving engine w/ a 11k redline, strictly for drag purposes, would i be better off w/ some backpressure, or none at all ??
6kW? that is way too much power to gain from just exhaust mods. That comes out to about 34hp. Please explain.Sunder said:I didn't lose or gain in the low end (because the back pressure was still there) but from 4000rpm, I gained about 6kw till redline at 9000rpm.
It’s more like 8HP like Sunder said but just to let you know if you treat the exhaust lit a full system and upgrade it like one the gains will be more. For exampleBlackEG_Si said:6kW? that is way too much power to gain from just exhaust mods. That comes out to about 34hp. Please explain.
I totally agree. Too bad most people don't treat the whole system.ich_folge said:if you treat the exhaust lit a full system and upgrade it like one the gains will be more. For example
Head work “the exhaust actually starts here with the exhaust valves and runners
Header “SMSP can net you 15HP or more”
Cat “better flowing cat that is”
Piping “less restrictive less bends and higher velocity”
Muffler “don’t know why I put this here it does nothing for performance
I can see 30HP or more from doing all this