So right now my current setup is LPP LT's and ORY with my stock SLP dual/dual catback to my CME. I'm getting a used GMMG setup for Christmas and have have to have the I-Pipe custom made. I've been listening to clips and the GMMG seems pretty damn raspy under normal driving conditions. Because of this I'm looking into getting a Magnaflow high flow cat and putting it towards the beginning of the I-Pipe. So I know this would help tone down the rasp but would it hurt performance any? I don't really care it it robs a couple HP but it wouldn't be anything big right? I'm more concerned about just getting a nice good sound out of the exahaust.

Btw has anyone done this and have pics of it? Thanks guys.

Can a Mod move this to the external engine section please?

 

It might take away a little bit (3?), but I'd rather have a good sound.

 

So you're guessing like 3 HP loss? Better sound is definately worth that. I figured that it would take no more away than what I would gain by getting rid of that real flat pipe over the axle on the stock catback.

 

I just noticed I posted this in the internal engine area can a mod move this to the external engine section? Thanks.

 

Well, thermodynamics proves that there should be virtually no loss with a cat. It's an engineering thing, and its hard to explain, but you can do that and be fine. Personally, I would go to a dynomax bullet or a spiral flow muffler. A spiral flow actually accelerates air and flows very close to straight pipe if not better.

 

GMMG sounds like total **** without cats IMO. Putting a cat in the I-pipe would clean it up a lot.

 

To say the least. It took cats, a powerstick in the I, and resonator tips to get mine to sound good. Dunno if a single cat in the I would do it.

Interested as to why you wouldn't do the usual two cats in the Y? Of course costs double.

 

I already have the ORY as I've had the headers since March. I'm just now getting the GMMG, and yeah it costs double. Its a lot cheaper to spend $65-95 for the cat than to get a whole new catted y. I've heard some clips on here and youtube where it sounds OK without a cat, just a little rapsy and some where it sounds really raspy. Because of this I think my best option is to just go with the cat. I'm not looking for a performance gain out of the cat or another muffler, I just want something that takes away most of the rasp and deepens the tone.