I just wanted to start off by saying i'm a lite tuner. i'm a proud owner of an evo 8. My question is this aside from stock number of horsepower. i'm curious does anyone know how much horsepower i have gain from just a perrin downpipe and cat-back exaust from apex N1 . I understand it varies but man i really can say there is a huge diffrents in driving the car. just curious how much. Just in case ur wondering i didn't dyno my car and i really don't plan to. So any lite tuners out there can help me out , Thank you in advance Drive safe racers

 

i think you would have to tune the car to get the most out of it. i voted 15hp

 

I vote about 10 without tuning. I have an Apexi N1 Downpipe and a Apexi N1 cat-back, still using the stock cat. The evo does feel different with this set-up. Feels a little faster. But imagine with tuning.

 

if you don't change the stock cat to either a test pipe or hiflow cat, you're not really gaining anything since the exhaust will bottleneck there. everything from that point back is not getting any use. it's like pinching a straw in the middle & trying to suck thru it. try it to see how hard your car is working to push out that exhaust. + you might want to specify if it's WHP you're trying to gain & yes you will need a retune.

 

i just recently installed a HKS hi power ti muffler with costum 3inch pipeing along with a 3 inch test pipe from ultimate racing, i can still feel the difference in my car from stock. i voted 10 hp from this set up at least maybe even more. no way to know unless you get dynoed.

 

I am waiting on a Ultimate Racing Test pipe now that I ordered from http://www.z1auto.com