I have Kooks 1 7/8 stepped to 2" headers no cats.

I'm having a shop make true dials off of the Flowtech 3" X-pipe using a pair of Spiral Flows most likely.

Would I have enough flow with 2.5" piping after the X or should I bite the bullet, get the PHB relocation bracket, and run 3" piping?

I don't wanna run 3" piping just for 3" sake if it's overkill.

Thanks in advance!

 

How much power do you plan on making? If I remember correctly 2 2.5 duals are good for just about 500hp without any loss.

 

That's off for me though.... 1 7/8" stepped to 2"..... I assume 3" Primaries..... 3" X pipe.... Then slam it down to 2 1/2" inches?

I just don't see the logic according to your sig, but that's just me.
Let that motor exhale!!

 

I agree with you.

I was just researching all options before I put on the 3" duals and dropped my Corsa (I really like the Corsa sound ).

 

I ran 3.5 inch duals on my 402, fwiw with the 1 7/8 stepped to 2 inch kooks headers, headers had a 3.5 inch collector.

 

You'll be OK with dual 2.5" after the X. It will be ever so slightly quieter than dual 3" and flow slightly less. Dual 3" will flow more, for sure. Is it needed to "support" your power level? That's a misnomer and there's more to exhaust flow than pure size (bends, spikes, equal length, etc) though it's a biggie. Give me a pro dual 2.5 over a hacked dual 3 any day. Given your excellent headers and the "relatively" low cost of the PHB relo, I'd not want any bottlenecks at all, especially given how much LS motors like to breathe. Personally, I'd do dual 3" all the way with dual cats. Not having the smell and knocking out rasp even more is worth it to me. Regardless, you're going to love the sound of true duals with an X, much smoother than the Ypipe. You won't miss your Corsa...

 

fwiw, I didn't run any X or h with my dual 3.5 system. A pair of super 44 mufflers, ran the pipe right out in front of the rear wheels and that was it, just ended it under the car and painted it all flat black.. couldn't even see it.

Sounded great and didn't cost the car anything over running it with open headers.

Don't get all tied up in that x and h pipe nonsense. If you run a big enough system, you don't have to worry about any of that. And, not running it over the axle helped save about 20 lbs off the weight as well... which never hurts.

I personally hate the way a corsa sounds, raspy as hell on every car I have heard with one.

 

It's 3" or burst for me, with Magnaflow, till i can find something flowing and sounding better...

I like that 3" X pipe