awilli6

Hey gang,

I have a 89 with x-pipe and RMB. With the RMB the exhaust is too loud. I want to try and get the same sound I had with my 87 with same x-pipe and RMB. I know the resonator is different between the 87 & 89.

If I was looking for a similar aftermarket resonator to the 87, what would I ask for with a muffler shop? Is there a borla or other resonator that will allow me to run with both RMB & x-pipe?

Thanks for your time

Ash

Mongo

What about a resonated x-pipe? Dynomax and Magnaflow sell mufflers with an internal "X". You can still maintain you scavenging and enjoy a quieter car.

FredR

The exhaust system with x-pipe, mid resonator is going to be too dammed loud for anyone with normal hearing capabilities. I had my x-pipe, a custom welded-in decent sized Bullet muffler and the RMB instead of the stock setup- sounds good, not overly loud but they can still hear you coming! During my annual Gov inspection in October 2019 a very sharp young inspection officer from the police complained about my exhaust being non standard and noisy. I explained to the nice officer how the stock system was damaged before i purchased the car 17 years ago and how the originals are no longer made so we made a good effort to install something "reasonable" and they duly passed it. Last October I felt as though I wanted something a bit more quieter so re-fitted the stock rear muffler- very pleased with the result, still a bit rorty - no complaints from the inspector last October- sailed through- they did not even test emissions!

So, if you have it, just fit the stock rear muffler- that will probably solve your problem!

hernanca

I don't know if those smaller GT resonators were always just "resonators" (hollow, no absorption material). One cutaway I saw showed nothing inside around the perforated pipe, but it could have blown out over time.

From what I had found (see pics - not mine) the larger mid-MUFFLER is much different than a hollow resonator.

I would think most aftermarket straight-thru/absorption mufflers (borla, magnaflow, etc), whether bullet type as Fred used or the larger oval types are going to only be a little quieter than the GT resonators and nowhere near as mellowed as the double-walled, heavier & larger stock mid-mufflers you had.

To your question: I would just be sure not to ask for a "resonator" - if the difference is what I think it is (resonator = hollow; no stuffing) and they understand that distinction, you will get a hollow can without the absorption material of the stock larger mid-mufflers. Ask for a good "straight-thru", "absorption" muffler. The larger the space around the pipe, the quieter it should be, assuming good absorption material that wont blow out over time.

Have you considered sourcing some S4 mid-mufflers? If the 87 and 89 S4 cams are the same (I don't recall - I know the 89 GT cams are different), then you should be able to get the sound back.

If you want to save weight by going aftermarket, however, the cost may be loudness.

awilli6

Thanks for all your inputs. I really liked my 87 sound. I will see if 928 International have any available. If not, I’ll be sure not to ask for a resonator with the aftermarket guys.

hernanca

I am also assuming your 87 and 89 both have the same cat set up (both cars have cats or both cars don't have cats).

Let us know if 928 International does not have any available at this time. If you keep this post up long enough, the right person with the right stash may come across it!