A little question about exhaust.

[OnlyMe]

I just wanted some opinions since I have been hearing mixed things about axle back and cat back. I have a 3.5 coupe with a AEM intake, borla ale back and a UD pulley going in this weekend. Is it worth it to make the borla into a full cat back system? I mean will the extra air flow help with anything? Also if I should what size diameter should I go? Thanks in advance......

[RicerX]

Hey man welcome to the forums.

First off - I've posed the exact same question. From what I've read, the two most restrictive parts on our cars lie within the Y-Pipe and the rear section (muffler, this is the part that the Borla/Tanabe/Stillen Axle-Back will replace).

If you do both Y-Pipe and the Borla exhaust, there probably won't be any point to replacing the piping in between them, as the difference you'll get will probably be 1 or 2 hp at the very most. IMHO, when you're getting around 5-10 out of a good axleback (I know that's a fairly broad range and the upper end is almost unlikely) and 12hp/15tq out of the y-pipe, making the borla into a catback probably isn't going to make much of a difference, if any.

If you do decide to replace the piping, 2.5" is a good size for a non-turbo V6, or will even be sufficient with a smaller turbo setup later if you decide to do one. I only see heavy turbo setups run 3" to, in some cases, 4" piping (yikes!). 4" I've seen in 240SXs that are very heavily tuned.

Hope that helps!

[OnlyMe]

Thanks for the welcome glad there is a wesite out there for lost people, lol. I have never thought aout getting the y pipe for my car is that something I should look into? The only idea I have had was going to full cat. Would the y pipe be a better investment then just the cat? Going with the y is there any extra labor or just taking out stock and putting in new pipe? The Y pipe is suppose to give 10+ hp?

[Beak]

ya man.. our stock y-pipe is very restrictive. you will see better gain in hp and tq if you just get the ypipe rather than just getting the catback. but put them both together and you will see a nice increase

[DJ_B_Easy]

I would have done the Y Pipe before the exhaust. Cheaper and more noticeable results. BUT, to each his own and sounds like you have some scratch to toss around, throw the Y in!

[OnlyMe]

Hey guys thanks for all the help with this. And DJBeasy I would have got the Y-pipes if I known better but thats why Im here now to learn, lol.

Guess I will be ordering the Y Pipes this weekend. Thanks again guys.

[DJ_B_Easy]

By no means am I saying you made a mistake, if i had the money to do both Y and exhaust (or an exhaust period) at the same time I would have. You are going to have a nice set-up in a short amount of time, you are going to love it!