i read a lot of things how adding a full exhaust system on a 4 cylinder will give you 20 hp or your money backi dont think so i think if you just put one on and dont tune your car up to it like your intake and **** you would get like 1-3 maybe a little morethats just what i think maybe im stupid but tell me what you guys think
You would probably get a 20 horsepower increase with a complete exhaust, if other parts were already upgraded. Like decent heads (or head work) and intake manifold. A header would likely be the biggest improvement in an exhaust system, some stock manifolds are highly inadequate and restrictive.
maybe, if you do CAI, header, then 2.5-3 straight pipe with a good tune. a really good tune. also depends on the car. some cars respond better to bolt-ons more than others
Im sure on my car that an exhaust will give me 20hp. The 4cyl must be turbo and must have alot of boost Im pushing 25psi out of a Holset HX35 My exhaust gases are flying out and the least amount of restriction getting out the more i can get in there. Now a naturally aspirated 4 cyl will most likely loose hp due to lack of backpressure if they decided to go to a big exhaust. I have a 2.5in o2 housing and 3in exhaust the rest of the way back.
