Hey guys, what's up? I need your opinions and isights on something. I'm thinking about gutting the cats on my Trans Am, my only exhaust mod is a hooker catback. I was wondering if anybody has done this on the stock y-pipe. If so how did it sound? I'm more worried about sound than horsepower. Also, do you think welding a straight pipe in place of the cats might be better? Any thoughts would be greatly appreciated. Thanks.

[ January 30, 2002: Message edited by: BlueBird99 ]</p>

 

I’ve got gutted stock cats on a stock Y-pipe with a Flowmaster cat back right now. There is no rasp and it sounds great! I used to have straight “race” pipes (made by Mufflex) in place of the cats, and I was still using the stock Y-pipe and same catback. With that setup it rasped horribly. I guess the gutted hollow cat shells have acted as “rasp eliminators”.

 

I gutted my cats on my 1998 ws6 and it seemed to help, the sound was not so bad due to the fact that i was running the stock muffler at the time. A few months after i put the Borla on and it did increase the sound but itwas not that bad under normal driving, at full throttle it sounded awsome!

 

I think that www.ls1speed.com sells pipes that will bolt in place of the cats. Rather than guts cats that cost like $200 each to replace that's what I would do.

 

[quote]Originally posted by Pro Stock John:
<strong>I think that www.ls1speed.com sells pipes that will bolt in place of the cats. Rather than guts cats that cost like $200 each to replace that's what I would do.</strong><hr></blockquote>

PSJ...I bought an extra set from a guy on the boards who went to LTs. I paid like 50 bucks for them both. Not a big investment to get rid of the God awful rasp if you ask me...

 

I bought my straight pipes through speed inc (Sponsor).. They do have a ras from 2200-2500 but noticable improvement on motor and jug.. Volume is awesome too now..

 

Bluebird99,

I'm assuming you have a 99. I have the SLP dual-dual on my 99 with "modded" cats. The car is a bit louder but not obnoxiously so. Idle sound is mellow and sounds quite good when you are way into it. Since I left both cats in-line there is no rasp as the chambers actually act like resonaters (as RPW WS6 stated).
One thing you will want to do if you have a 99 with the passenger cat located under the passenger seat is to get rid of the dual walled pipe that goes from the manifold down to the cat. The inside diameter of this pipe is 1 and 7/8ths, talk about restrictive!!! You will need to custom make this piece yourself (with the assistance of a muffler shop). Good Luck.

 

if anyone is interested in gutting stock cats I have a set of ungutted stock 99ta cats $45 shipped

 

On a '01 Z will they just unbolt, or do I need to cut and re-weld??? And just to make sure, one more time, the SES light will NOT affect performance with this particular "mod"?

 

Well, I've decided to go ahead and punch out the cats. Hopefully it'll waken up my exhuast a little. The hooker sounds sweet but I'd like it a little louder without the rasp of "race" pipes.

Jacobi, I'm almost certain that the SES light set by this mod won't affect performance any. I have a buddies with a 97 and 98 Z and they both picked up a little in the 1/4. Sounds badass too. I went ahead and picked up a set of 02 sims just to be on the safe side, plus that light would annoy the hell outta me. <img src="gr_images/icons/wink.gif" border="0">

 

It'll probably annoy the hell out of me too...I'll end up getting the 02's...but here's just one more question! What do you think the dealer will think of this light? Let's say I have to take it in because of a synchro, or a blown speaker...or they going to give me trouble because of the light, or will they overlook it? I know SEMA says the broken part has to have been affected by the aftermarket one, but that's not really the case here.

 

It depends on the dealer, I guess. There's no way that the gutted cats could affect a synchro or a blown speaker, so they shouldn't. But if they give you a hard time about it, raise some hell! They're bound to overlook it eventually. <img src="gr_stretch.gif" border="0">