Need you all's opinion on this subject. Is 2" piping from header back going to be okay in an F/I setup with a Greddy Supercharger or should i say will it be suffecient. I have a DC Sports Axle back and it is 2'' so i would like to just extened on to it. I really dont want to have to buy a new larger diameter exhaust if i dont have to. But please give opinions on the subject, Thanks.

 

bigger is always better on forced induction, however you can keep the same piping, it just may hold back a few ponies and some highway power. i can understand if you want to keep it quieter. but if i were you i would probably go atleast to 2 and a quarter.

 

Bigger is always better, i thought size didnt matter, I thought it was the motion in the ocean.
Sorry i had to say that, but thanks for the response, i would like all the ponies i ca n get out of it, but sound and money are my main holdbacks on a going bigger.

 

No you need 2 1/2 inch piping. 2 1/4 is for NA xB's and thats what I have. I have a couple frineds with F/I and they both have 2 1/2 inch piping. One with a turbo and one with a S/C and the 2 1/2 piping was recomended by their tuners.

 

Darn, thats what i was expecting to hear. O' well time to save some cash up and get a new exhaust with 2 1/2 i guess. Thanks for the input.

 

It shouldnt cost you that much for new piping. Over here I know some places that charge 80 bucks for some piping installed.

 

Is changining the exhaust piping diameter really going to help all that much seeing as how the header outlet is still 1.75"? It seems like it'll bottleneck at the header outlet. Wouldn't a freer flowing exhaust can be the solution to reducing the stock exhaust bottlneck?

Reason I ask, I'll be running the Greddy S/C soon, but so far in terms of exhaust all I've done is upgrade the header. I can justify removing the high restriction stock muffler can for a free flowing unit, but I just don't understand the need to move to larger piping when your limited to 1.75" at the header. Is there something I'm not taking into account?

 

Well if you go the TC route a new header will be installed with the turbo on it, so a bigger outlet may be used. With a SC, then you use the exsiting header, so im not sure if it will bottle neck. I am no where near an expert on the subject, we will have to wait for some one else to chime in on the subject.

 

I spoke to a few people and I get the same repsonse: without increasing the total exhaust path, it won't flow any better. The only thing that could help, short of a custom header & exhaust is a freer flowing cat and exhaust can to reduce potential bottlenecks.

Final thought: Even if it did help, it probably won't be that noticable on our cars. Unless your going for every availible horse, it's probably not worth the investment.

I will, however, get a straight thru Elisper axelback exhaust can w/silencer to help seeing as how the stock muffler is probably a bit too restrictive for F/I. It won't be put on until after the S/C is on though. So I'll keep you updated if you'd like, ProshopXB.

 

Sure please do, i will let you know how mine works with a TC, which will be in by the end of May.

 

2" is plenty on a 1.5l with 5-8 lbs of boost from an S/C
header outlet is 1.75, cat outlet is 1.75.
you already have a highflow cat and 2 inch piping, you're set.
is all the effort and money to get another half inch of diameter that might yield an extra 5 or so horses worth it to you? put the money towards an sc kit in my opinion.

 

I forgot to add that since this thread started a month ago, i changed my full header back exhaust out with 2.25 piping and a high flow cat.

 

...and that your now going turbo...