928NOOBIE

I've been looking around at forum posts and am struggling to find a muffler to fit in the pumpkin area for the early '86..I've got some new MSDS headers (ceramic) and a shop is willing to fabricate the rest but they are nervous about putting a muffler underneath due to vibration and clearance concerns.

They are also likewise trying to figure out what they can put in place of the pumpkin with the tailpipes going out the side.

Early '86 has duals but they don't split ahead of the rear...they both go around drivers' side...so I don't have shielding on passenger side that could accommodate anything.

I'm considering rebuilding the inside of the pumpkin itself...some of those angled vanes or something ...anyone have any suggestions? Only making 1,000 of these cars really makes it tough to find something suitable.

I've considered a couple options: http://www.flowmastermufflers.com/hp-2/

That being one..for under the car..or using the "shorties" version of that in place of the pumpkin but the shop doesn't really think either of those are going to work very well for same reasons.

As I've mentioned above...I've done searches and looked at pictures but pretty much everything runs a dual system with passenger side pipe crossing over in front of the rear.

I'm really leaning towards rebuilding the inside of the pumpkin...if anyone has any experience/pics of this I'd love some..I think the shop would be willing or know someone that would be if there was anything to go on....thanks guys.

ptuomov

What vibration or clearance concerns? There's "natural" room for three mufflers or resonators in the 928 S4 undercarriage. It's all very well heat shielded and otherwise provisioned for. There are three support points, each close to the mufflers, which allows for using thin wall exhaust pipe even with heavy mufflers. The support points allow for use of rubber isolator. What's the problem in terms of construction, clearance, vibration etc.?

In terms of sound suppression and power for a normally aspirated car, in my opinion you want a crossover of some kind pretty close to the header collector outlets (use pipemax to compute the best and worst locations). Then you want a rear muffler in the space of the pumpkin. Finally, two mufflers or resonators in the locations forward of the rear axle. Features beyond that are in my opinion fine tuning.

On the real estate previously occupied by the pumpkin: There are a number of universal mufflers that fit in there, but none of them use the space very efficiently (and neither does the GT rear muffler). Gutting the pumpkin is a relevant option as it uses the space efficiently, but you'd have to actually know what you're doing in terms of sound waves to make it better than "too small" universal muffler. I don't, so my next exhaust will have a universal muffler there.

928NOOBIE

Hey Ptuomov...I will keep in mind the crossover...I am seeing that...but I have S3 early '86...so there is only one small place for a small resonator...it's tiny..covers both pipes..this exhaust is tough with not having the passenger-side pipe crossing over ...there's no provision made for mufflers in that space.

I found a NOS muffler but they want almost $800 for it. Mark at 928Int'l has one for $350....I haven't checked with them yet so condition is unknown.

I am thinking the best bet may be to use the stock muffler and a crossover at front...maybe an X somewhere towards the rear...

Appreciate the input. Not familiar with pipemax...I'll check it out.