I know a large decrease in back pressure can hurt an NA motor. I plan on a HUGE turbo project late this year. For now, after I lower the car an inch or so, I want to work on the exhaust. I will probably buy a couple of A'pex N1 mufflers and slap them on the stock piping. I don't want to buy a full exhaust, because for the turbo, I will need a 3" diameter, but that is way too large for NA. Has anyone done this, how does it effect sound? Pictures?

 

Large decreases in flow velocity hurt performance, engines do not like backpressure. If you go with an exhaust too big, below a certain amount of flow you will have a mass of used air "parked" in the pipes blocking what is coming out of the exhaust ports.

Rob_O

 

A single 3" way too large for NA? not from what i know... a dual 3" would be if thats what you're referring to

a 3" single exhaust would be perfect; or a 2.5" dual

 

Really? I didn't think a single 3" would be good for an NA application. More like a 2.5"...But anyway, I think I may just keep the stock pipes for now, and put the mufflers on, and upgrade the piping after the turbo.

 

are you talking about a 300 or 400?