a-fuso

GMC Owner
Mar 28, 2012
1,856
77
48
CA
you don't want backpressure.. ever.. it's always bad.. yes, it is possible to go too big on the exhaust and kill low end power, but that's because of overscavenging the exhaust and causign the air/fuel mixutre to blow straight thru the chamber during valve overlap and not because of the lack of backpressure.

Listen to Bryan, he owns race cars...






But really, what he just said is completely correct, backpressure is not needed or wanted unless you have a 2 stroke. On a car with longtubes, you need the exhaust pipe to be the right size so exhaust gas velocity stays high and exits the pipe on its own without the engine having to work extra to push it out the pipe.
 
Listen to Bryan, he owns race cars...






But really, what he just said is completely correct, backpressure is not needed or wanted unless you have a 2 stroke. On a car with longtubes, you need the exhaust pipe to be the right size so exhaust gas velocity stays high and exits the pipe on its own without the engine having to work extra to push it out the pipe.

:rofl: