What are the optimum exhaust sizes for a stock sr20de? What about a mildly prepped one? What about a race motor? All NA of course. I've never gone bigger than 2.25" on a NA motor, but those were all rwd cars and under axle which had very little bends. Would in be better to go 2.5" on a FF car where there are quite a few more bends in the exhaust system?

I suggest 2.25 is the best for Allmotor/Nitrous...2.5 for T25 setup, 3inch for all other turbo applications. The greddy SP was great when i used it all motor and nitrous. And i am currently running 2.5 on BB motor. So these suggestions are through experience.

I have 2.5 catback and all i have is i/h/e.

2.5 inch for a High HP engine is just fine. So is 60mm. I have a 2.5 on my VE and gained 12whp and lost no torque or hp at any point on the curve. I was dynoing at 172whp at the time.

I would suggest http://sr20.net/mirrornet/sr20deforum/forumimages/top_search.gif. You won't find THE optimum size, but you will find what most people use.

Basically, the larger the pipe, the more towards top-end performance it's biased. How much top-end do you want?

I just converted to 2.5 exhaust today and Im loving it. :cool:

Thru my research and experience, if you're putting out high HP numbers on a 2.0 ( over 150whp ) , slap in a 2.5 exhaust.

WATCH THAT REDLINE.:eek:

If you are NA and runnig nitrous then 2.5 is fine, other than that stick to 2.25 to keep gas velocities high in the exhast stream. I fyou are running boost then 2.5 is smallest and 3" is optimum. But 2.25 will handle all the bolt ons including cams.

Brent

I just converted to 2.5 exhaust today and Im loving it. WATCH THAT REDLINE

lol why do you say that? im doing exhaust soon and im very torn between 2.25 and 2.5.. i wanna tear shit up with I/H/E/P!!!!!

Originally posted by nx2000racer
lol why do you say that? im doing exhaust soon and im very torn between 2.25 and 2.5.. i wanna tear shit up with I/H/E/P!!!!!

Well, I have this crazy relationship with my motor. I dont have a radio in my car so I FEEL IT AND LEARN IT.
Im going to Dyno it again here soon.
Im telling you NOW I expect to see 155 or 157. If not more.
I have a very effective CUSTOM intake and now I have a CUSTOM exhaust.

My motor likes 2.5.
I like 2.5

If you are going to limit your bolt ons to CAI,header, pullies I would go with a 2.25.
If you have a goal of going with more mods than the listed above, I would say go with 2.5 Loosing a little on the bottom now isn't that bad when you save up for cams in the future.