I'm getting ready to purchase longtube headers for my WS6, and was wondering if I really need my cats? I've heard that taking the cats off when you have the GMMG exhaust destroys the sound, but what about the GMMG with longtube headers and no cats? Have any of you installed longtubes without cats and have a GMMG exhaust? Also, I'm not totally positive what "rasp" is. Can someone give me a detailed description/example of rasp? Thanks


BTW, sometime this summer I will be installing the Thunder Racing 224-112 cam, so will the cam help with the rasp? With headers, cam and GMMG should I go catless?

 

i say yes...the sound should still be there. remember the chambered mufflers were comon fare on the old muscle cars...and they didn't have cats

rasp is the harsh, tin-y, loud rattle from the exhaust gases reverberating inside the tubing and muffler. it is basically a byproduct of low restiction exhaust. it is usually more prevailent in the higher rpm range.

for me i don't really care...cause if i'm running over 4k rpms...i'm racing...and if i'm racing i don't really care how the car sounds

i toned my LT, orp, and magnaflow by putting an 18" dynomax bullet muffler on the end of the Ypipe. it doens't rob any hp and it tones the exhaust down a bit, since the MF is one of the most freeflowing muffler-ed systems

 

I have FLP LT headers and the GMMG. The headers come with ORP and cats. I have run it with both on the car. It definitely gets a lot louder wit the ORP on it. I prefer it with the cats on it. It even got louder after the cam installation.

 

How does it sound with the cats on? Does it get raspy with the cats off and the ORP on? Does it sound terrible with the cats off and ORP on? I'm afraid I'll destroy the sound of my GMMG. With the cats on, is the GMMG deeper and louder? Please give me as much information as you can. Trying to make a decision is driving me nuts!

 

I like the sound better with the cats on. It's a deep low rumble with the cats on. Very loud with the ORP on. Just too loud for me. With the cats on reminds me of the days with a Chevy V8 with Glass pack mufflers. A low rumble. All this is my option of course.

Ralph

 

Definitely run CATS with your headers going through the GMMG. Wonderfully deep muscle car sound at any rpm!

Without cats, it sounds terrible in my honest opinion. The sound gets very raspy in the mid-range and the tone is a lot more noticeably unrefined (sounds like a Loudmouth or cutout this way). If you actually want your LS1 to sound good without cats, then run TRUE DUALS.

But trust me on this as I've heard it both ways...

Mike

 

Catted y-pipe it is then