Bill Ball

Same with my 89. X-pipe + RMB = WAY too loud. I've heard the same X-pipe on an 87 with RMB and it was not nearly as loud. It was fine. 87-88 has larger resonators and they seem to be a better match for an X-pipe and RMB. So, I'm looking for 87-88 middle exhaust sections as I would like to run the X-pipe. I have dyno documentation of a 30HP/30 ft-lb gain from the X.

Ispeed

I just went back to a rear muffler. Small resonators, no cats, and an '89 GT rear muffler. The '89GT/club sport rear muffler is lighter and louder than the later GT/GTS twin pipe mufflers. The part number ends in "...03"

p.s. I ran this same set up a few years ago and it was quite good. I have also done a rmb on a stock '87 with big resonators and it was more muted than with small resonators or with an X pipe.

RKD in OKC

If you do the X-pipe, resonators and RMB and still think it is too loud, try adding sport cats. They are so open they have little effect on HP but do tone it down a little.

click here

Dan87951

I would do a X-pipe if you want some extra umph. I think I had clogged cats but it really helped my S4. I have an X-pipe on my S4 daily driver with a GT rear muffler and its not to loud at all. These cars aren't rockets by todays standards but the 2.20 rear end I have in both my 87's probably isn't helping. Now only if someone made after market gears... The S4 engine is a great engine if its in good shape just needs help getting the power down IMO.

No_Substitute

I'm 42. Have a RMB. Love it. I can tiptoe out of my neighborhood without anyone throwing rocks at me, and stomp it when I am out of the residential areas. Makes me feel like a kid again.

JPTL

IMO, the 32v engines with a RMB is music from idle to redline. Whether you're 7 or 75..you just have to like cars, and appreciate the sound of a nice 32v V8. There are very few cars on the road that sound as sweet, IMO. At low speeds, the RMB isn't loud or raspy, the way a Harley is for example, it's more of a throaty rumble that never gets too loud or earthshaking. I can't speak for the X pipe RMB combo, but it looks like a unanimous vote for "loud".
So thinking of this leads me to a question:
If cats aren't required on an '88 S4 ('Historic' registration), can I run an X pipe while keeping the stock S4 muffler and see the reported 20-ish hp gain...while keeping the db's toned down so as not to shake up my neighbors too much?

RKD in OKC

Several years ago I had a 90 GT. RMBs were available but x-pipes were not. The consensus here was gutting the stock cat and RMB added 15hp on the dyno. Adding back the rear muffler cost 3 hp on the dyno. On the 90GT gutted cats and RMB were way too loud. Stock cats and RMB were wonderful, just right. After gutting the cats on my 90 GT I put back on the rear muffler. That is why I wanted the sport cats with the x-pipe and RMB, to turn the volume down just a bit. Extra power even with sport cats is the difference between street tires and track tires, ie., acceleration wheel spin the same with track tires and x-pipe as street tires with stock h-pipe.

F451

I agree wholeheartedly. It lets you hear the rumble of the v8 the way it should be heard. At idle it is not loud or obnoxious at all. I always take it easy out of my neighborhood and have not noticed any negative looks or comments.

When I put mine on, I wondered why I had not done it sooner.

And if you buy one and decide you don't like, they are easy enough to sell.

Now, the RMB with the X-pipe? Different matter.

Also, rmb cuts a lot of weight off the extreme end of the back of the car. Not a big deal, but every little bit helps.

turbochad

I just changed out my stock H pipe and SS RMB for a Motorsport SS X-Pipe, sport cats and stock GT rear muffler. My car is a '90 S4 and has the small resonators. I actually like the sound of the stock exhaust and RMB better, but the X-pipe did added some extra ponies and still sounds great (not quite as loud at the back of the car). I also like the look of the twin outlet GT rear muffler better than the RMB. Overall I like the new setup, and the car is more fun to drive with the extra power. Hope this helps.

I have the RMB for sale, it is still in great shape (my car is very low mileage).

Ranfurly

Hi

I getting one put on my 1990 S4 on Thursday so I'll be able to report in - I'm going for a bit more noise when the gp pedal is pressed

blown 87

My 87 now sounds great with a RMB and one of DR's H pipes.

As has been said, not near as loud as a later car with a X pipe and a RMB.

redpathtribe

Just do it! An RMB is the next best investment next to wheels on a 928 IMHO. The sound is intoxicating, people inside and out love it. Have had nothing but compliments on the sound. It sounds like a high performace euro design V8 should!

bigmac

I have Carls SS exhaust with a RMB. It sounds great. Had new tires and alignment at Local
P car dealer and service guy commented on how good it sounded.