[QUOTE=XSNRGE;383859]Thanks for the response guys! I’ll be PM’ing you in the future when I have some more questions regarding my build!
R33, I believe a 3" exhaust does lose power… I’ve got a 3" Bee*R on my SOHC KA. Only mods other than that are intake pipe and HKS filter. The moment I removed the silencer from my exhaust, I really noticed a loss of low-end torque. The mid-range climb to top-end improved by quite a bit, but it wasn’t too much of a drastic improvement to justify baiting your car with a loud exhaust with only minimalistic gains.
If I could do it all over again, I’d be running a 2.5" high-flow cat and cat-back… As for 2.5" cat-backs, no clue on what to run with, though…
very well said thats exactly the result u loose lowend torque but gain minimal up top…2.5 inch exhaust have proven to be fine up to 400+ whp
People always think bigger is better,they always forget about functionality,do you possibly think any 4banger boosted producing 400whp flow`s more exhaust gases that a v8/v10 producing 500whp or even 400whp,they run 2.5 99% of the time. think about this and answer ur question for urself…
Please tell me how many 400whp sr20s or ka-ts you know exist here on SON lol 1,2,3!!!while those v8/v10s are N/A they still flow more than any 4banger @400whp. you are right turbos do like flow and a smaller exhaust would be more of a restriction at high rpms, BUT its still not necessary for a street machine even @400whp… alot of guys have run 11s even 10s on 2.5 inch exhaust without any issues.(always remember the practicality factor when building a street car)
now if ur talking a full race/track car then its a different ballgame.go big 3inch 4inch whatever or take it off completely ur the man more power to you literally…
KA love. Dan’s dyno shows that a n/a ka24de can make almost as much whp as a stock sr20det and for a lot less. was your car a auto-5spd swap? I think the auto ecu on a standard car leans it out and does give it some power. Dont have anything to base it on, but I used to have a auto ecu and recently swapped to a standard ecu in my 216k+ oily KA… with the auto ecu my KA was seeing quite a lot of 7.5k rpm(no rev limit), backfires and a lot of abuse hence the switch to 5spd ecu, which sounds mellow in comparison and a little less power. hopefully if my car is on the road soon with itb and 248/248 cams i’ll get it to the dyno and see how much power it makes.