Cliff Ruckstuhl

I was lookinf at this and thought about adding it this summer any thoughts? We do not need to get our cars tested so I could run with no Cats. I did the muffler by pass and really like that.

Cliff 87 928 S 4

the flyin' scotsman

Cliff.............do you know which resonatores are on your car?

Cliff Ruckstuhl

No I do not

Cliff

the flyin' scotsman

ok.............there were 2 types fitted to the S4; large and small. The larger apparently do a better job of muffling the noise. The smaller were fitted to the later S4and GTs.

I had a RMB with a Motorsport X and my stock 'smaller' resonators and the noise while 'Ferrarish' at lower rpm became irritating at WOT.

I removed the RMB and refitted the stock rear muffler but that was too quiet and IMO ugly.

I then fitted a GT rear muffler, sounds and looks better with the X and small resonators.

the flyin' scotsman

Attached are the resonators:

Cliff Ruckstuhl

So what do the Resonators do?

Cliff

123quattro

Cut down on resonance usually around the torque peak and reduce overall sound output slightly.

the flyin' scotsman

The original exhaust system for you car is headers to cat. convertor to the resonators to the rear muffler.

The resonators are a mid muffler, quiet the exhaust note and remove resonant frequencies. Even with my resonators in place my car 'resonated/vibrated' with exhaust noise with the RMB and X.

Back to your original question; the X gave my car's engine the freedom to rev quickly, more power and a richer tone. The Motorsport version fits well but I did weld the rear of the X to the resonator pipes to ensure a positive/tight seal.

Cliff Ruckstuhl

So the X will be on the list of things to buy in a month or so. I'll make the car to 928 Specialts and talk to them about it some.

Thanks

Cliff

ROG100

Both my GTS and 87 S4 run with the X pipe and stock resonators as well as the rear muffler.
They have a growl at WOT - aggressive but not to loud - suitable for my taste.
Both have cats. Tried my GTS without cats and no discernable difference in power or sound.

Cliff Ruckstuhl

Just so I have this right,If I add the X pipe and no cats I will pick up some horse power and a little better sound? 928 Specialst says on ther web site I will pick up 24 wheel HP.

Cliff

ROG100

Cats or no cats you will pick up a lot of horsepower - as much as 30 RWHP.
On the dyno we did not see any reduction of HP with or without the cats (91GT)
I did not notice any "seatofthepants" difference.

RDS928S

The car will stink badly with no cats at idle.

RDS

the flyin' scotsman

My car was worse with the cats..........to my sniffer that is.

Dannyfumi

Just added X-pipe with Rogers help, well he did it all! I have the hi-flow cats, but the power gain is immediate and obvious! The cars exhaust note is civil, but will give a very nice growl when stomped, best investment i've done!

Dan
85s 32v-manual