I THINK so. I do not have one around here to test it on, tho. But I don't see why not.

 

Carl, sounds great! Is that with normal cats and a RMB?

 

I've read the whole thread and I'm alittle confused about the purpose of the the new intermediate muffler which you're selling. Assume what's on the car works, isn't corroded, and doesn't need replacement. what does it do?

1. add some small amount of horsepower by decreasing some exhaust retriction in the stock intermediate muffler

2. increase the sound over the original (might depend on whether it's an 87-88 big muffler, or 85, 89- smaller resonator)

3. decrease the sound if you have an 85 or 89- resonator, exspecially if you hvae x pipes and rmb, such that you can now confortably (noise wise) run all both together where the consensus is that you can't now (because as Louie or who ever said, the resonators are too small in these years and he recommends no rmb

4. also decease the sound as stated in 3 above for 87-88 S4, lowering the sound either more or less because the sound wasn't as loud with rmb and x pipes because of the larger intermediate muffler

5. not known at this time awaiting further testing

6. none of the above

Guess the big question would be for performance people is what does it do for rmb and x pipes, louder or softer than stock, per the difference in model year resonnator.

you'd think there'd be a simple straightforward answer, eventually at least.

 

Yes. Totally stock from the cats to the engine. Stock cats.

 

Rickjaffe -

The answers are 1 and 2

I'm not sure about "small amount of horsepower" - we received 28 HP and 35 Ft Pounds Torque on the '85. That's pretty good. I would expect not as much of a HP improvement on the already-less-restrictive 1987 and up. Until I get a before-and-after from a '87 to '95 car, I'd speculate about 20 HP.

But lots of guys feel the 928 is over-muffled, and they want to open it up a little so the world can tell its a V8 under that hood... but not so much that they cannot have a comfortable conversation in the car. We have tried to hit exactly that sound level.

 

do you think it would add 20 hp if the car already has x pipes and rmb. Heard that in general each system upgrade is not necessarily additive, if other upgrades are also present. I understand that it's fully documented that x pipes ad about 24 hp, question for a guy with x pipes is how much of the 28 over stock would be added to x piped car.

also looks like it wouldn't be a solution for someone like ed hughes who wants to quiet down his car, or someone who removed rmb after installing x pipes because the combination was too load.

in my case, the learning is that an 87 (or 88) can do rmb and x pipes because of the bigger intermedaite muffler/resontator. since your solution is creating more flow/less restriction, logically that probably means more noise. So the issue for guys like me would be would a smaller, or more efficient/less restrictive intermed. muffler push it over he edge noise wise.
maybe that's what needs to be determined through testing or installations.

 

That is some of the purpose of the test. I want something different than the sound I get from my X pipe and RMB. I don't want to throw the muffler back on.

 

Got your pipes fitted yet Ed?

Looking forward to 'hearing' about the results.

 

seems to me that it would be a pretty neat trick to decrease exhaust pressure or resistance, increase flow AND decrease sound. Could see it changing the pitch of the sound, and possibly make it less intrusive, but make it quieter in terms of decibles, like I said, that would be a neat trick, and I'd wonder whether that would be possible from a fluid dynamics or whatever the applicable science of this is.

 

Ed fitted them up to his 91 GT and although one side fit pretty well, the other did not. That's a surprise considering how well they fit on the '85 here - but then again, that's why we offered them out there for testing.

I am picking the pipes up from Ed and they are going back to Stebro for investigation along with Ed's most excellent photo essay he made for us.

The owner of Stebro is working with me and totally commited to a perfect product (he always is). We will get this sorted out and Ed will get another set of pipes.

He did report, from the short time he ran the 91 with our pipes on it, that he liked the tone and sound level... but was unable to drive it, just run it in the driveway, so we cannot be sure yet.

Our 928 exhaust pipe jigs are still setup, so I expect a pretty quick turn-around.

 

Carl,
Excellent customer service.

 

The pipes have been adjusted and shipped back to Ed to fit up to his 91 GT again.

 

The pipes will be here on Monday. Unfortunately, I've got my 911 rebuild project kicking off ahead of me this next week, so it'll be the following week before I get to this, I think. I'm going to try to see if I can sneak this in somewhere soon. I'm anxious to see what this setup does.

 

With my new x-pipe catless RMB and resent noise ticket I put the Muffler back on. I ordered 2 bottles of Viagra just to drive it after getting used to that wonderful sound then loosing it again. I have a local shop that will make what ever I need I don't think I want to pay 1K to replace the whole thing. Has anyone placed a muffler in the rear to get a midrange level of sound if so what brand and model number. Any feedback would be helpful I did ask this before but did not get a lot of feedback on the subject.

 

Ed, what's the latest on this? Are you going to dyno & post results also?