M. Schneider

On a scale of 1 to 10, 10 being the loudest and RSR mufflers say a 5, what would the sound level be with a gutted cat and a stock muffler set? ; Louder than RSRs? (with a cat) (My stock mufflers are: 993.111.045.11 Gillet)

Edit: Alternately, to what degree of influence, Sound Pressure Level (SPL) speaking, does the catalytic converter have on the stock 993s exhaust system? "And the survey said!"

flatsixforme

I'm curious as well...

TAI2

Why carry the extra weight around if it is gutted?

axl911

Can't answer your question directly, but I have a LPMM (1.5 inch bypass) muffler. I then added a Fabspeed cat bypass. Sound level increased by at least 5x. At WOT, it is makes the "scares women and small children" kinda sound. Whereas, with just the LPMM muffler and stock cat makes a "yeah, that is a sport car" kind of noise.

Afraid I am going to have to switch back to the cat.

TheOtherEric

I'm surprised you got no answers. I've tried a lot of combinations (but not this one) and I'd guess it would rate about 5 or 6.

kdurg

I've not tried gutted cats with RSR's or Stock muffs....but I have done:

Stock Muffs/Stock Cats. Boring
RSRs/Stock Cats. 3 sound level
RSRs/Dach Sport Cats. 5
RSRs/Cat X by pass pipe. 7
Fabspeed Super Cups and Dach Sport Cats. 9

I know Mark in Baltimore is running Supercups AND X By pass and its gotta be a 10.

Eric has ran several combinations too.......maybe he can elaborate.

But why bother gutting out the stock cat at all ? I say get a Sport Cat setup (200 cell) you'll lose weight and still be green.

M. Schneider

Hey TA12 in Jersey ~ (my former home town)

Because a gutted or hollow catalytic converter is free. A catalytic converter replacement X-cross pipe is in the $750 area. A gutted cat and an X-pipe are similarly positioned, basically speaking, with mufflers terminating the exhaust system.

I’m playing around with the idea of gutting the cat’s in an effort to enhance the exhaust note of the 993; to a degree. My circumstance (Vail, Colorado registration) allows for sacrificing the cat., converter.

M. Schneider

Hey Keith (kdurg) ~ Now you're talkin. Thanks.

TheOtherEric

I've tried all those combos that Keith describes, and I'd agree with his numbers.

Except supercups & bypass would have to be like a 12 out of 10. Yikes!

M. Schneider

I can't help but replay the scene from This is Spinal Tap were Chris Guest is convincing the interviewer of an amplifiers numeric scale, that of 11. One louder than ten. A Classic, hilarious!

Me thinks I'll try gutting the cat and running with the OE mufflers as a first step.

Thanks for all the input.

TheOtherEric

Keep in mind that you can often find used cat bypass pipes for under $300. A good alternative to destroying your stock cats, plus they'd weigh less.

Just a thought.

Stealth 993

I can only speak for what I have.
95 C4 stock, with Motorsound intake, 1 maybe 1.5
97 C4S, DACH Cat pipe, Motorsound intake & mufflers 3.5, still want more from it!
But I love the rasp, crack & burble on the C4S!

I might end up with Supersprint mufflers on the C4, with a DACH pipe.

axl911

I am taking my Fabspeed bypass off this weekend. Hint. Hint.

M. Schneider

Now,, that's a thought an orphaned Fabspeed by-pass pipe; em??

Truthfully my first thought was to inquire with the guys who are participating in the DACH 200 cell cat group purchase. Each one will have an orphaned OE catalytic converter, some headed for the garbage dump. For my test purposes one of these orphaned cats could be a gut operation candidate.

All that being said, the Fabspeed by-pass tactic would be a whole less weight. . . .

Bill Verburg

I've used the following & relative sound quantity & quality 10 is loudest
RSR w/ Fabspeed cat bypass 7 (not legal at LRP)
stock w/ Fabspeed cat bypass 5 (what I find best all around)
straight headers 10