This is for 88SE and eventually 90GT.
Neither car has or needs Cats

Having run the GT with gutted cats and an RMB it is too loud ( I like it but there are times when it attracts all the wrong sort of attention)

So I have an X on order and I have two choices muffler right behind the X where Cats would go on a cat equipped car or Muffler at the rear.

From a pragmatic viewpoint, muffler behind the cats is preferable as I have 3 Rmbs already - and I like the look but if there is a signicant performance advantage to an X, straight pipes, small resonators then rear muffler setup then I might be persuaded.

 

So where's the question? Do you want us to persuade you?

I agree that an X-pipe with with the GT resonators and an RMB is just a tad bit on the loud side. So I am currently running the X, GT resonators, and then the stock muffler. It could be a bit louder, but I'm okay with it for now. I'll put the RMB on for special occasions.

Oh and I do not have any cats or other mufflers on the car, although I've thought about putting something just after the X and then running the RMB.

 

For what it's worth, I've dynoed my 91GT with an X pipe with high flow cats with and without the stock muffler and found zero difference in HP. I'm using the RMB because the stock muffler's too quiet for my taste.

 

Find some '87 mid mufflers (same as the '86.5) and use those after the x and have them dump to one of your rmb's.

It is loud only if you really get into the gas, but a nice quiet rumble otherwise.

 

Left side has a slight bend difference at the muffler connection. Right is the same.

I'm wanting to try GT mids, with my debaffled 86.5 pumpkin, and mod'ed Ott-X. It's altogether too quiet, right now.

 

Yes it is too quiet, a 928 with 312rwhp should sound like it has 312rwhp!!

 

strange.... X-pipe, no cats, and GT mufflers aren't loud to me...

 

uk 86 with ott x and rmb but standard mid mufflers was very loud - but i loved it!

 

Replace the GT mufflers with Magnaflow or Borla straight throughs as large as you can fit in the spaces next to the tranny.

 

Anyone run a Lomas X-pipe with the hi-flow cats thru stock S4 mid mufflers and an RMB?

That is the combo I've been planning on as long as it is not too loud. Don't want to rack up any more unnecessary tickets..... Would rather be stealth-like, but with the extra performance and a nice burble. Also would like to avoid any low-res frequency droning noises that would wear on you.

 

x pipe with RMB is pretty loud Chris

 

Was hoping that the cats and stock (or maybe aftermarket replacement?) mid mufflers would make it livable..... maybe just wishful thinking cause the rmb just looks too cool. Would go with the performance of the x-pipe if i gotta choose though.

 

x pipe is 20hp, so thats what i am thinking about too

I am looking for a dual in dual out muffler to replace the RMB, something like a straight through design but that has some sound suppression qualities as i do believe the rmb and x pipe is a bit much.

 

I'm having the same dilemna..

Loudness is a factor here in Sydney.. I've met a few people who got issued roadside EPA noise tickets for violating the Australian Design Rules (national standard for drive-by noise test is 90 db).

If you get a noise ticket, you not only have to go in to the test centre to pass a noise test, but also an emissions test (there's no regular emissions testing in this country.. yet).

I'd pretty much come to the conclusion of using an X and keeping the stock resonators and rear muffler for noise reasons.

 

I tend to like the sound with S4 resonators, cats and an RMB. It's not bad at all in my opinion. Without cats is a different story, and with GT resonators/no cats it's "attention getting" loud. With the rear muffler in place it's simply too quiet for my tastes.