Ketchmi

The Flowmaster system would probably be a bit louder than the stock cat/GT resonator/RMB system. The cats to a very good job of dampening sound. It would certainly be quieter than the X/GT resonators/RMB catless.

The Dynomax are not quiet. The Borla's do not come in a large enough size to dampen well given the restrictions of the 928. To get the same level of sound from the Borla's you would need to add another muffler at the rear, like the factory did. A catless X with just a pair of Borla's would be close to GT resonators.

byrdman454

Exactly what I wanted to know. Thanks Dave.

Now, when exactly are those babies going to be ready to ship???? HAHA

Please keep us posted on this.
Thanks

RDS928S

What diameter is the stock exhaust system on the 85/86 side by side dual set up?
What type of gains can be expected when replacing with 2.5 diameter system?
I already have the Motorsports x-over with no cats.

Thanks Rich

byrdman454

If it is like the S4, I think they are 2.25" diameter.

I believe Louis Ott was getting about 12-15hp increase with a 2.5" diameter cat-back with Bullet brand mufflers. This is from his website.

BTW, these Bullet mufflers Louie was using are no longer available...discontinued.

auzivision

I couldn’t exactly figure out how to navigate the Motorsport website.

I’m interested in updating my S4 which already has an RMB. It sounds like (no pun intended) that the S4 resonators are a little bigger so I could get away with an X pipe plus high flow cats, using original S4 resonators and my RMB. I’m hoping it’s not too much louder than my current setup (stock S4 w/RMB).

Couple questions I have:

1) Is this a bolt on procedure or will it require cutting and/or welding to install?
2) What options should I consider (i.e. material type, Cat size)?
3) Are these available today?
4) Is your website working properly?

I really like the look of my RMB and don’t have the original muffler, so I looking for options to work with what I have without causing my neighbors windows to rattle.

Ketchmi

Sorry, our website is pretty much fubar'd. We will be building a new one as soon as possible.

The "X" is a complete bolt on, no cutting or welding required. The cats are 100 cpi spiral wound metal matrix, they are currently our only option for 32 valve cars. With the larger S4 resonators and the cats you will have a slightly louder mid to high rpm sound, but not overly loud by any means. If you were to put your rear muffler back on it would be as quiet as stock so I'd keep the RMB.

They are available, in stock and ready to ship. I have 3 of them going out today...

byrdman454

Dave,
Any updates on the 32v cat-back?