Porsche Enthusiasts Club Forum

Quick Question...

I have just bought a twin tailpipe S4 back exhaust box to exchange for my single oval S4 tailpipe on my Black '88 S4. I have always liked the twin tail pipe version for looks but wondered if there was any real difference between the two back exhaust boxes or are they just a straight swop for looks only?

I am going to try to check the differences in weight later today and also if the twin tail pipe diameters coming out of the muffler on both versions differ any? I will post what I find later on.

If anyone has gone through this before or knows of the differences it would be great to hear your findings

Many Thanks

Steve

I measured my two spare back muffler boxes that I have - 1 is the std oval exit pipe from twin outlets and the other is the one I mention at the start of this thread - the twin outlet tail pipes.

Interestingly enough, the twin pipes that go into the oval muffler are of a fabricated design with a weld seam down both sides of the pipes running axially. They measure 54mm diameter OD from top to bottom and 57mm from side to side - but this is across the weld seams so not the true diameter of the pipe.

The new muffler I bought has the twin outlet pipes and they are decidedly larger with 60.34mm diameter OD. They are of a solid pipe design and are only welded at the joint with the muffler body. They look very similar outlet pipe designs to the Paul Anderson one's from the muffler to the pipe tip.

Can't wait to get them on and see how they change the exhaust note & resonance.

I didn't get chance to weigh them today...but might try that next weekend as I have the front of my 928 up in the air as I'm changing fan belts and checking for my oil cooler leak at the moment. So 1 Job at a time! :):)

Thanks

Steve

Steve,

I have the twin pipe back box, and my exhaust is VERY quiet.

I think the note comes from further up the system. Jason Sloan from the 928 list lives not far from me and his exhaust can be heard from 2 streets away, but funnily enough is no louder when you stand next to it. He has fitted a different middle section to his exhaust. I'll email him to find out what he fitted.

HI Lee

Nice car! I guess my tin pipe back box is similar to yours then. I have had contact with Jason before on 928.org I imagine his sounds very loud

Must be good to have 2 928ers a few streets away from each other.

Steve

Hi Steve, the problem is Jasons' 1991 GT is faster, in better condition, louder and generally much nicer than mine. I'm always the poor relation at the back.

Hi

If you can find it, years ago on here I posted about the weights of rear boxes....from memory the standard rear kidney shaped dual outlet S2 BOX WEIGHED around 30 lbs The RMB was around 10 lbs I think....

All the best Brett

Hi Lee

You could cure the "faster" problem lol...Nitrous....hehe

All the best Brett

And not tell him 'till we got on the straight He would sh*t himself. That is a very good idea, next year maybe if I have the money

Here's a photo of the Rear Twin Pipe Muffler I bought.
Just need to clean them up and polish them twin pipes!

I do have 1 chrome tailpipe cover but only one....so either need to find a new pair of Chrome tail pipes or find a matching one to go with the one I already have.

Steve

Well spent a few mins looking at tidying up my twin pipes as suggested. ...
- Removed all the rust with a brass wire wheel
- got some emery cloth & oil and in a long length & started the "shoe polishing" technique and after 10 mins or so..voila!

Need to try some metal polish as suggested but they have certainly come up well. Not quite as good as a chrome tail pipe yet....but getting there.

Cheers
Steve

What was the original style of the back box on a 87' S4?

Mine has a huge back box (RMB i think) and I want to downscale it.

Way too loud and boy racer for me

The original back box whould be a muffler similar to my post photo's but with a twin out pipe set going into a single oval chrome outlet pipe. An RMB is simply 2 pipes replacing the back muffler box completely.

Do you have a photo of your back box? I have a spare original one if your interested...I maybe would swop you to see what sound you would get from yours on my set up. PM me!

Steve
bizman928@hotmail.co.uk