If I had the glasspack that is in place of my cat removed and just had a staight pipe there. I know it would be really loud...I am just looking for the best performance.

 

What kind of cat-back system are you running?

 

it would be like a Loudmouth system, with no cat...

so you'll hear it

probably pick up 15hp over bone stock (don't say if you are or not) between ditching the cat and adding a freeflowing exhaust.

the interior resonance will be pretty bad if you end the straight pipe under the car...i would run it back to the rear and put tips on it.

 

Some of you need to go back and READ the post. I doubt you will see/feel any difference between the pack and a straight pipe.

 

I have a bullet muffler in place of where the Cat goes. I can switch between the two very quickly.
The bullet muffler I think flows better than the glasspack, maybe they are the same.

Anyway, it is louder and sounds super sweet with my close plate Borla catback. I can feel a slight increase according to the but dyno as well.

 

It would add a little more noise and a little more power.

 

Does the Bullet muffler still tame your exhaust at all? I just put a high flow cat on and the ****ing thing glows and rattles so i think i'm just gonna put on a bullet muffler. I like the way my car sounds with the cat on but the other stuff is just a pain.

 

I have an old cat. conv. body that had blown itself out. I put a 3" piece of pipe down it and had welded a flange on the front to my y-pipe. This and my stock cat. conv. are the same length and setup so I can easily swap the two out for emissions testing. Yes, there is a large difference in sound between the two.

 

Ditto. I don't know how exactly an exhaust fits in the equation fuel + air + spark = power.

A few hp's from less flow restriction if the right setup is put to use, but 15 hp's....whatever.

 

dyno testing shows that modern cats pull off about 5 horsepower (per Dave Vizard), so unless your glasspack is more restrictive than the original cat (and it may well be), you will see a max gain of those 5 horses