View Full Version : 3" exhaust

11-14-2005, 05:05 AM
um... what would 3" exhaust (4 1/2" tip) do to for a 1990 st? IS 3" to big? Would it hurt performance?

11-14-2005, 05:14 AM
I think it would drown the poor little 1.8L.

11-14-2005, 05:31 AM

3" on a 4afe is Ridiculously WAY WAY WAY too big.....3" is considerd for TURBO cars only due to the fact the mass amounts of air is SHUVED out. Just think about it 3" on like a 95hp motor? You will mostly likely lose power if not just no gain. Some supras in the 700-1200hp range go 4-5 inch so you know you deff wont need that big of a pipe for a 4afe

Brother did while he had it though and went with 2 1/4 Inch Stright pipe..very illeagal due its right under gastank and that was LOUD.

11-14-2005, 05:31 AM
try 1.6L :/

11-14-2005, 05:33 AM
wow... yea i thought so. Just wanted to make sure :)

11-14-2005, 11:03 AM
For an 4AFE....2" is pretty much all you need for a 1.6L engine, even when you're keeping it in the high revs. For the 5SFE's 2.2L, 2.25" is typically considered ideal but only if you plan on keeping the RPMs high.

Basically, you try to match the exhaust size to the amount of exhaust gas you're producing, to achieve the smoothest flow. Pipes that are too big actually make the exhaust system flow less smoothly (this is where the backpressure myth comes from, but big pipes actually create a form of backpressure when paired with too small an engine). Bigger engine -- more exhaust gas. Higher revs -- more gas. Tiny little engines works best with tiny pipes.

11-14-2005, 11:09 AM
awesome, thanks.