David L. Lutz

Could someone tell me the difference in sound of a GTS rear muffler vs. the mufflers used on the S4's? (currently I don't have either)

I would be running a "X" with no cats, '87 S4 resonators. Currently with this set up and an RMB it's just too loud!

Glenn M

David,
I also have an 87, x-pipe, no cats, sort of an rmb (fuchs rmb/muffler but most of the muffler is gone). I don't think it is very loud, my 88 with the smalller mids and true rmb seems louder. I find a big difference between the small and large mids. Not sure about the sound difference between the mufflers, GTS is lighter. My S4 muffler is quiet but not sure with an x pipe.

Glenn

David L. Lutz

On my '87 with cats and the RMB it was not loud at all. But when I removed the cats and added the X (I think the cats really made the difference) it is just a little over the top and I am looking to tone it down a little.

Thanks

aggravation

I bought Mongo's Flowmaster Super 40's and replaced my resonators with them.
Before it was X pipe>resonators>RMB , it sounded awesome but way too loud, I found my self driving very light footed on the throttle when I was around town because it was too much.

The Flowmasters didn't change the over all tone very much but they took the edge off, both at idle and at WOT but it still sounds like a hot rodded Porsche.
If you ever played electric guitar the difference was like throwing a blanket over the face of a Marshall stack, the ***** and dynamics are still there but now you can stand in front of the cabinet without the pain.

pcar928fan

GTS's are WAY quiet and have the same mid resonators (or close to it) as the '87, '90-'91 cars. I have an RMB on my '92 and it was a real downer when I started the car and it didn't sound ANYTHING like my '88!

David L. Lutz

Marshall...

Ispeed

I had lomas X, no cats, small resonators and rmb, sound was great but rated "R" and not "PG".
I added cats and it is acceptable for most people and driving with a nice sound. Happy now.

jon928se

I would say Lomas/Motorsports X, no cats, small resonators and RMB probably qualifies for "R" and "18+" or is that "21+" in the US ?

X + no cats + Small resonators + SE/89,90 GT rear muffler is quieter without loosing the edge but I think that X + no cats + magnaflow or similar +rnb will probably ba about right for me.

Mrmerlin

I have a an X, no cat ,small resonators(GT resonators) and the GT rear muffler, I think this is a good compromise, As I had an RMB fitted and it was like standing next to a Nascar the GT muff quieted things down but it still has a growl and has a Perfect GT sound.
It comfortable on the freeway as a normal conversation can be had.

ROG100

Will the GTS rear muffler fit the 87 system?

Jim bailey - 928 International

Yes Roger the GTS rear muffler fits ... there is little if any difference in the rear final muffler ......it is the ONLY muffler. The other two are resonators dealing more with tone than volume. The factory cats being three chamber ceramic honeycomb do much to break up the pressure waves and sound. The "GT" resonator is smaller and lighter I do not think the rear S-4,GT,GTS has much more different than just single vs dual pipes welded the the back.

Okv

Thanks for more info on the exhaust, interesting.

I postet about the rear muffler, asking for dimensions of GT muffler - seems like I saw wrong, there is only one muffler listed in PET.
Still, one reply states that the 89 GT muffler is louder.
May also very well be that the PET lists only one muffler, as it is mechanically interchangable, even though different versions were mounted originally, for different model (S4/GT) and year.

I am still looking into making my own rear muffler, but first I think I will do a sound measurement and recording for reference, both with stock muffler and RMB.

Jim bailey - 928 International

The smaller two resonators on the GT change the tone of the sound more than anything else. Burble, burble, burble, ...

Jerome Craig

I have the stock exhaust/cats with the "GT" resonators and the "GT" rear muffler. Carl a.k.a. "928andRC51" pointed out that my rear muffler has a different part number and when you thump it, it has a very hollow sound compared to the "stock" 87 muffler. My muffler has dual outlets with anodized copper tips. The GT resonators have a much deeper tone than the stock resonators and there is a bit of a drone at low speeds, but it gets quieter as the revs increase. They also weigh about half as much as the larger resonators. WOT is marvelous! In my opinion, this combination produces a refined "exspensive" GT sound.

Just my $0.02

ROG100

GTS Muffler heading your way David.

Jim, Thanks for the confirmation O Great One.