what is the better set up a 3" w/out cats or 2.5 w/cats
I will have the fac. turbo unit TXS chip up pipe
what do, you guys think I should buy 3 or 2.5

thanks

 

i think the 3" catless will be faster.

Cops are the only reason catless is a bad thing.

 

Yeah, the 3 inch catless will definitely give you a bit more top end but I'd be willing to bet that with your setup the 2.5" would give you a wider torque band (read: better for everything except the 1/4 mile) and would keep you out of trouble with the po pos because of the cat.

 

I'm running a 2.5" turboback (scoobysport) w/ the 3rd oe cat (front midpipe). I had to leave (or replace) one cat for scca classifications. I chose to go w/ 2.5" for the wide torque curve and better low/mid range torque, it also enables me to utilize the 3 rd oe cat. I don't plan on turbo upgrades as I need the quick spooliong TD04. Alot of it comes down to what you want to do w/ your vehicle.

big sky

 

Does anyone how big the performance differences are between the two? Is there a noticeable difference? Dyno charts would be great, but butt dyno comparisons are fine too.

 

2nd fastest suby here on the island with one hi-flow cat on my car

Is that enough for you palaban? Lets put it this way, you wont notice a difference whether you have a cat or not.

 

You mention cats plural- any system w/ cats in plural will pale to a catless system. If you make that singular and stipulate that the remaing cat is the 3rd oe cat or a high flow unit, the difference becomes small- 2 1/2 or 3".

The choice between 2 1/2" vs 3" is (used to be anyways) a pretty hotly debated subject. Again if I was going to stick w/ the oe turbo, 2 1/2" would be (is) my choice.

Getting rid of cat #1, 2 is probably the most important consideration in any exhaust upgrade- this frees up the most ponies.

big sky

 

Thanks tevia boy. I was thinking about being a tree hugger, but with all you upgraded turbo guys running around, I'm going to need all the help I can get.

Good luck at the track. Let's hope you're not 2nd fastest for long.