I emptied my cat a while back on my 84. Yes, I could tell immediately that my performance was much better. But the exhaust was noticeably louder. I have the stock exhaust system. I didn't want to do anything that would restrict flow, so i chopped out the mid muffler/silencer/resonator or whatever it's called. I was able to fit a flowmaster flowfx that has a 14 inch body (2.5 tube size). It required a bit of hammering to spread the heat shield and a section of the tubing had to be bent to get the front opening to fit.

It's a straight through muffler with a slight bend in the internal tubing (cuts drone). I wasn't expecting much but the reduction was pretty significant and i can't tell any difference in throttle response. I think I paid about $48 for the muffler and $65 for install. BTW, I'm not sure if the mid-muffler was packed with fiber glass when new and it just disintegrated overtime, but I can't see how it does anything to reduce sound levels. Whether it was supposed to rely on wave cancelling or absorption, it failed the "hold it up to your ear" test.

 

I don't know about '84 but for my '83S I spent a lot f money and time on the exhaust system and finally go with (Borla 78-82) cat back system with slightly modification (bending) and the performance and sound was great.

 

For an '87:

Stock manifolds, x-pipe, GT resonators, stock rear muffler

To me it's quiet, but not too quiet, with a nice higher-pitched howl.

For those that don't know, the GT resonators are much smaller than the S4's.

 

The race to make a Porsche sound like a pickup truck...

 

You must be referring to your own car since mine does not.

 

^^^^^ I had that same system on my 88 S4 its great, no drone and not too loud and easy to converse with the windows up doing 80.
NOTE swap out the rear muffler for an RMB and it turns an otherwise serene atmosphere into a NASCAR distraction.
I had a few friends that had wives that wouldnt ride in their car cause its too loud with the RMB installed.

 

"cause its too loud with the RMB installed" ...What is the RMB?

 

Rear Muffer Delete.

 

I was not.

 

If you want to make it quieter and not have a cat get a factory exhaust system and run a proper y pipe in place of the cats.

Since it wont have the expansion that a hallowed out cat has it is much less prone to drone. Plus the factory system is quiet enough but still sounds pretty good.

I personally have the "GT" setup (twin pipe rear muffler and small mid mufflers) on my 89 and it is definitely louder than my factory 85 with the factory twin pipe single mid and rear muffler setup they got.

 

Or " Bypass" = RMB

Ken
80 928S
5 Speed
UK

 

A catless Y-pipe to a Borla is a well-proven and great exhaust setup. If you couple it with the later round tube stainless manifolds instead of the cast ones, it gets even better. I have this setup on both my 928s - the supercharged 79 with the 83 4.7L in it and the 84 Euro S. Car sounds purposeful when punched and accelerating, like it should from outside the car, has zero drone anywhere in the RPM range, and with A/C on and windows up cruises at 90 mph or better very quietly and comfortably, as I drove home from Frenzy running 90-95 mph most of the way, and even averaged 18.5 mpg doing it.

Here you go.

 

I like the sound of the Borla system.
The issue is that I've yet to have a single muffler of their not crack at the seams.
And while they had (not sure if they still do) a "lifetime guarantee", I was never able to get them to send me a replacement muffler, up front.
And sending a client's muffler off for 4-6 weeks, for them to look at a crack they have seen 10,000 times, isn't very practical...I simply don't have room to store cars for a muffler.
So, Borla's "lifetime guarantee" has always been a complete joke, for me and most everyone in the repair industry.
I've tried a couple of times to explain this to a client...not easy to do.
Therefore the Borla thing is a complete non-starter thing, for me.

 

Hmmm, I've read other posts on here from people who have gotten a complete new system from Borla under their guarantee, and quickly. Think it may have been a post by cobalt or it's the user in the NE that has a cobalt blue older 911.

I've also reached out to them with a question and received an answer the same day. Maybe it's all in who the inquiry gets routed too, IDK.