Right now I have HRC downpipe to the flex section in my closet... cannot install it because I need to buy catback. Im AUTO and built and running 5psi nor because of rich issue and tuning, but I will up the boost to around 10psi or 13-15max on race since its a daily driver. My car is lowered on H&R Sport, road here suck and I was wondering if 3" will not be too low on the ground ? And since I dont want to pass 15psi will I loose power with 3" on daily driving ?

I was thining of 2.5" with high flow cat ? Will be easier to install and no hitting the ground issue.

Finaly, if I look at my HRC downpipe the flange to connect to the catback is a 3 bolt desing, all I see is 2 bolt on catback on ebay, what do you do to connect the hrc 3" to a 2.5" catback ?

Thanks

I am running 8 psi and i could not believe the difference between stock and 3" all the way back. Not to mention the EGT drop. I spent around 300 bucks on the entire exhaust system and it was totally worth it IMO.

Originally posted by RfOeCnKdOeNr
I am running 8 psi and i could not believe the difference between stock and 3" all the way back. Not to mention the EGT drop. I spent around 300 bucks on the entire exhaust system and it was totally worth it IMO.

Same here from stock to 3" was actually a noticeable difference all around, although 2.5" should suit your purposes just fine too.

As for the flange :shrug my cat has two-bolt flanges on each end, not sure why your dp has a 3 bolt flange

Its he hahn 3" eliminator downpipe. Do you guys are lowered with 3" ? hard to install and no grinding issue because its too low ?

I'm running a 3" stainless exhaust from the turbo back that I made myself and am lowered and have no scraping issues, I would say that my front bumper sits about 2" off the ground at the most and have never scraped anything, of course you have to be careful driving a lowered car anyway. I think a 2.5" would be more than plenty if thats all your going to be runnin boost wise.

Thats right, I will buy a 2.5" it will be enough for 15psi and this will not be all the time so... and im auto so i dont want to loose lot of low rpm power. But now all catback I see came with a 2bolt design and my "*(?$"*? 3" downpipe from hrc came with a 3bolt design do i need to cut the 2bolt flange and solder a 3 bolt one ?

I have a 1.75" drop front and rear with a full 3" exhaust. I run 10-15psi daily. It drives fine I just have to be careful of where the bumps are at. If your afraid of scrapping or have crappy roads you could go with the 2.5" and be fine.

As far as your catback, either find a catback with 3 bolt or like you said you will have to cut and weld a 3 bolt flange.

Lowered and 3 in. catback here. The thought of scraping my exhaust has never crossed my mind.

Plenty of room under my car with the 3". I can't see why it would be a problem.

Originally posted by ChloRure
and im auto so i dont want to loose lot of low rpm power.

losing low end torque? I think your thinkin along the lines of an N/A motor. Right idea, wrong situation. Corky Bell said it best "The best exhaust for a turbo is no exhaust." Aside from a small transition to smooth out turbulance, wich he later states.

I'm auto also for the time being, just keep in mind that the quicker you can get that turbo to spool up the shorter time you have to stand on the converter and wait for boost.

Originally posted by quicksilver99

Originally posted by ChloRure and im auto so i dont want to loose lot of low rpm power.

losing low end torque? I think your thinkin along the lines of an N/A motor. Right idea, wrong situation. Corky Bell said it best "The best exhaust for a turbo is no exhaust." Aside from a small transition to smooth out turbulance, wich he later states. I'm auto also for the time being, just keep in mind that the quicker you can get that turbo to spool up the shorter time you have to stand on the converter and wait for boost.

Yeah your right for the spool time, I was thinking that you need a little backpressure to make the car move and starting to built boost. Now im just ****ed to find a 3 bolt exhaust design.

Oh and is it better to find exhaust that go under or over the crossmember ?

I've had both and I prefer the ones that go under, I had a cheap ass 3" at one point in time that went over and it would bang on the cross member so much that I decided to make my own that goes under. Its kinda a tight fit up there. plus one that goes under is easier to install/remove if you ever need to. Is the Down pipe you have supposed to bolt to the factory exhaust or an equivelent? Otherwise my shop just started lazer cutting flanges and I might be able to set you up with the one you need to have welded onto watever exhaust you might get.