MK3 Supra Turbo looking to Upgrade??

[Supra Saiyan]

Originally Posted by cre

Ok... well, yes and no... Larger pipe HURTS scavenging... severely. The larger the pipe the lower the velocity and the more time gases have to cool and increase in density thus requiring more energy be expended to expel them. BUT, scavenging isn't terribly important in a forced induction setup.... it is fo a N/A application which is why you'll hear a lot of mechanics and tuners telling an N/A owner they're a dope for running a 3" or larger exhaust, too large a throttle body or intake piping. Scavenging is a where the high velocity of the gasses flowing through the exhaust create a suction which, if employed correctly, assists in the removal of exhaust gases from the combustion chamber on the exhaust stroke... in a turbo setup this simply is not possible as the gasses must be pushed in order to move the exducer. The turbo's exhaust, especially after the turbo, is much cooler and much denser thus it requires more room to flow without creating back pressure.... and no matter what you may have heard; BACK PRESSURE IS NEVER A GOOD THING!

So if you have a turbo you would say 3in exhaust is good, and NA should not be that large.. Like 3in.. lol..?