Carl Fausett

I have the first prototype in-hand from my tubing bender of this new exhaust product for the 928.

These are a perfect replacement for the 1985 thru 1991 intermediate exhaust pipe and muffler, and with an adapter, I may also be able to get them to fit to 1992-95.

All stainless steel including the mufflers, and each pipe for an aft of the muffler is one contiguous piece with no welds.

We are putting up on a 1985 here in the shop soon to confirm the fit, then we will dyno to ascertain HP improvement. I'll also record the "sound" so you can hear it. It will be sweet.

Designed as a component and to be a perfect fit to the Motorsport X-Pipe and a 928 Intl RMB. If a fella used all 3, (the X-pipe, this SS intermediate section, and the RMB) he'd have an all-stainless system that would be pretty loud. Or mix-and-match to get the sound you want.

aggravation

Looks sweet!
I currently have the Test Pipe (an H pipe instead of X) the crossover of the H is about 5 inches long, also the RMB and small resonators.
If I used these mufflers in place of the resonators do you think it would lower the volume?
I like the way my set up sounds right now except when I'm in town and above 3000 RPM's I find myself backing off the throttle or accelerating slowly to keep RPM's down because of the sound being too loud.

byrdman454

Is the tube diameter 2.25" or 2.5"? What kind of mufflers are those? How much $$$?

the flyin' scotsman

Carl...........they look as big as the '87 Resonator pipes..........are they?

Also, are you working on a rear muffler that would work well with the Motorsport X and GT resonators producing higher than stock hp while at the same time control 'noise' and be lighter (I know, not asking much).

I'm currently running the GT rear muffler with the above set up and find it the most suitable compared to a stock S4 muffler or a RMB.

Carl Fausett

The tubing is 2.25" to provide the best mid-range torque

The mufflers are straight-through all-stainless mufflers that will not blow out or burn out on a SC application. ("Packed" mufflers can blow out their gauze on SC cars)

We are having these custom-manufactured for us by Stebro - so you know the quality is excellent and the sound is great.
www.stebro.com

The price is still a little up in the air as the development is not concluded. But our target is around $658 for the pair.

sharkmeister85

Would be nice if it did fit. But it is quite different from my stock setup, so I'm not hopeful.
Glenn

aggravation

Carl, all other things being equal, do you think the mufflers you are using will reduce the overall volume levels more that the small resonators do? And if so by approximately how much?

MarkRobinson

Very nice Carl, I will attest to the 2.25 being perfect for the 928 applications: I too dyno-tested plenty of this same type of configuration, with 2.5" pipe as well.

mark

ErnestSw

Interesting. I was under the impression that Louie had done some testing and found that the 2.5" pipe was optimal. Do you Mark, or you Carl have dyno charts with the increased velocity/volume of air with the X-pipe with both 2.25 and 2.5" X back systems? Is this a torque vs. HP issue? With the low restriction cats and the GT resonators why would I expect any benefit for my GT?
Help us understand oh Royal Smart People.

goodspeed928

$?

Carl Fausett

There is a small improvement available in flow from ram-bent to mandrel bent tube, but as there are no mandrels available in 2.25", the ram bent process was used. Plus, the change in flow between the two methods on these broad radius bends in negligable. Mandrel bending really pays dividends where the radiusus are tight.

The focus here is on the mufflers and the use of straight-through low-restriction units. THAT's where we are picking up ithe performance. How much performance? Don't know yet. As I said - the 85 I am bolting them on to is going to the dyno this month, then we will know.

fabric

Ok, so what's the difference between a low-restriction muffler and a resonator? As the stock unit here is a resonator, my understanding is this is less restrictive than a run-of-the-mill muffler, but it could end up being similar to these low-restriction. Perhaps you end up with similar flow, but these are slightly quieter, actually?

regardless, sounds like there may be some gains from slightly better flowing pipes, and having them in stainless has it's own set of advantages.

Giovanni

"The price is still a little up in the air as the development is not concluded. But our target is around $658 for the pair"

ParkerC

Very nice!!!

I for one hope their a little* quiter than GT/S4 resonators...That way I can keep the RMB look and get an X without worrying about earplugs on long trips!

Even if its not quiter, atleast maybe it'll clean up some of the DRONE at w/HWY speeds w/X and RMB.

Parker
889285SPD

Tony

thats my concern, i want a bit quieter.
I just bought a little 50 dollar Db meter at Radios shack...pretty handy!
Ill probably post in a few days about what i find with my Xpipe, RMB and stock S4 resontators. Actually its the damn tire noise in the wheel wells thats the worse
FYI..in the meantime I just dropped the sound on our dishwasher by 4 dbs with some sound proofing inside the hollow door !!
And i wonder why my wife shakes her head sometimes.