Removing the Cats completely? Much gain in noise and HP?

Rizzo · Sep 6, 2006

I am looking at removing the high flow cats in my 98 GTS. Just wondering if it will get louder at all ( which is what I want ) and is there much hp gained with no cats Vs High flows. Also do the high flow cats still make the pipes a lot hotter or do they flow enough that they dont get too hot. If there is no noise or hp gain then I'll leave them in but if it will make it a little louder than they're coming out. I already have the Borla cat back. Sounds great but I like LOUD.

Thanks.

KWIK96 · Sep 6, 2006

Did this.
Too loud, way too loud.
Heat about the same.
Performance, not any better.

2001 GTS · Sep 6, 2006

I like it...with 1 muffler on each side of course

Asp Man · Sep 6, 2006

Not sure about the HP, but it sure is louder!
I've removed the cats and the side mufflers, leaving just the rear resonator in place on an other wise stock system.
I like it loud, and it isn't that bad until you open the throtle wide. You can still drive and have a conversation at the same time.
At 70mph, steady-state cruising, you can bearly hear the exhaust. There is less drone than with just the cats removed.
I love it, and recomend it.

EllowViper · Sep 6, 2006

Too loud with my Corsa system. I ended up installing 14" Dynomax "straigh-through" style round mufflers where each cat had been. This took the rediculious mufflerless Dodge truck sound away but I still have a TERRIBLE drone at 1500-2500RPM. At some point, Hi Flow cats will be the next avenue. Loved the sound of the Corsa w/cats, but the side sill heat issue was out of control so I went catless.

MoparMan · Sep 6, 2006

I've got the Mopar cat back system with Belanger headers and no cats. It's loud but not too loud and sounds pretty mean.

Cal Cobra · Sep 6, 2006

I did it, and I LOVE it. :headbang:

I have the Belanger long tube Tri-Y headers, and B&B 3" exhaust (I don't believe the B&B mufflers do much, looking through them, there's zero restriction).

I love the sound, especially at WOT. What I don't love is the raw fuel that dumps out on the back of my car in my driveway, in my garage, etc., and can at times look like a jet stream if you stand on it :shocked:

I just bought a Roe VEC1 from a fellow on here and I think once it's dialed in it'll help with the fuel situation.

Cal

twinturbo3150 · Sep 6, 2006

please speak up I cant hear

Cal Cobra · Sep 6, 2006

What's that you say?

Honestly it's not that bad unless you're really on it. I can carry on a cell phone conversation with no problems, or carry on a normal conversation with a passenger.

Cal

Mccarlin · Sep 6, 2006

With my borla exhaust and no cats it sounds amazing. Like an old school big block rumble. It DEFINATLY reduced the overall heat issue of the car. The internal cabin is much cooler and i can actually touch the side sills after driving for a while. I could not with the stock cats on there.

Rizzo · Sep 7, 2006

What did you all do for 02 sensors? Did you buy sims or just leave the sensors out? I've heard some guys have just removed the sensors and never had the check engine light come on and others have had the light come on once in a while.

GTS Bruce · Sep 7, 2006

You need sims only if you have rear or after the cat o2 sensors. Bruce

KMODStang · Sep 7, 2006

Have you seen the inside of a cat before? It is extremely restrictive. Removing them with the proper tune will give you an increase in horsepower.

RAYSIR · Sep 7, 2006

I put a Corsa 3" cat back on my 99RT with stock cats. Then after I bought my 98GTS I put Random HF cats and 3"(no rear resonators) It was way too loud for me and was annoying resonance on a long drive. Last weekend I put the Corsa on the GTS and Random on the RT. Both sound good now. I think the GTS trunk is a can and magnifies the noise. The RT it's seperated and can handle more noise. RT could go HFlo and no resonators easy. GTS NO. Keep the cats removing doesn't mke much difference except noise. After cat O2s are going to be on an OBD2 car or 96 and newer and something has to simulate a cat. :laugh:

JUCD VPR · Sep 7, 2006

I have B&B Headers and Exhaust with NO cats, it sounds AWESOME. Loud and mean!

AJT · Sep 7, 2006

Corsa, & no cats. Sounds great, like above its not too loud until you get on it. I can idle out of my neighborhood with no problem.

andy

KepRght · Sep 7, 2006

ill tell you how it sounds & dyno's by monday.

removing stock cats, adding belenger long tubes, already have borla cat back

LETHAL GTS · Sep 7, 2006

Sean,
When are you going to get your *** out here?
You can hear mine without cats (B&B freakin loud) and my buddys (Borla not as loud) without cats.
Better hurry before the snow flys bro!

Sam 01 RT10 · Sep 7, 2006

I had no cats or mufflers on the '01, just an H-pipe where the rear muffler goes. The reduction in heat was quite noticeable, but that's here in Vegas. I thought it was great sounding. Ask Matt(Mopar Man)

sparty116 · Sep 7, 2006

Pretty loud while in the gas. Belanger/corsa/no cats here. With a nice cam, sitting in traffic can be pretty funny. People think its an all-out race car during idle, especially when idling @ ~600 rpm. Once you are in the gas, you'll damn near blow out car windows when you pass.

Rizzo · Sep 8, 2006

Sean,
When are you going to get your *** out here?
You can hear mine without cats (B&B freakin loud) and my buddys (Borla not as loud) without cats.
Better hurry before the snow flys bro!

It's harvest season buddy. Too busy to even drive the Viper other than to work but it should be over soon and back to normal.

LETHAL GTS · Sep 8, 2006

Giddy up man!
We're waitin!
BTW why does it always take you gappers so long to harvest. Kidding bud!

KMODStang · Sep 9, 2006

does anyone have any video or soundclips with different setups?

Removing the Cats completely? Much gain in noise and HP?

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