Grant27

So I am looking into a stainless steel exhaust for my '86 951 and am wondering what the best muffler is for a 3" no-cat system.

I know this can turn into a lot of fancy theory and such, but I am mainly looking at what is the right sound.

I know many people say that it is as simple as choosing the right muffler for you, but I have never seen a real way of telling what the sound is going to be like,

So,

can anyone list the different mufflers and describe how loud they really are? real numbers like dB would be nice, but it is understandable if this data does not exist!

Other than that, what do you guys choose to run and how do you like it?

Thanks for any input!

Jherriott

I went from stock to a 3" Ceramic coated full stainless Fabspeed Motorsport exhaust from down-pipe back w/ cat delete.

I hated the sound at first because it was very raspy/ricer sounding especially when cold, got better once it got hot. Now that it has had a year of soot deposits inside it, the tin-like sound is gone... much softer.

I think there are better choices of muffler if you like a deeper sound, but the quality of the pipes were top notch.

Stock Sound:

https://vimeo.com/30293163

Fabspeed 3" Sound w/ cat delete:

https://vimeo.com/65110954

Chris@Fabspeed

Our current muffler is a 3" straight thru muffler designed for maximum power. I am working on a different muffler, for those who want increase power but a better sound. Should be ready in 2 months or less.

gruhsy

You must post a sound clip when you get it's done

odurandina

run an SLP loudmouth resonator to a good exhaust like a Fabspeed or Lindsay w/ an 18"X8"X5 3"in/out Magnaflow.

it'll sound awesome.

LUCKY DAVE

I have wondered about this too.
I'm thinking about putting a 3" exhaust on my track car, but it needs to be pretty quiet for Laguna Seca.
Magnaflow? Borla? Other? Which one flows well enough while being nearly as quiet as the stock system (no cat)?

964-C2

I have the same question.. I have a 3" broadfoot system, and it is to loud for both street and track.

Chris@Fabspeed

one thing you can do to your current mufflers, broadfoot included, is weld one of these in:

http://www.dynatechheaders.com/access_vortex.html

jerome951

I've got the Magnaflow. Nice, deeper sound than stock. A buddy has a Borla and it's a little more race-car sounding.

I can't comment on volume over stock on the track. My wastegate dumps under the car so that's all I hear when I'm on the gas.

Grant27

Jerome951, So would you say that the magnaflow is quieter than the borla overall? I like the race car thing I think, but if it is twice as loud then maybe not.

964-C2

Thank you for your tip! Do you have any experience with it when it comes to how much it will reduce noise or flow?

This one looks like it will help reduce noise too, but I guess it is rather restrictive (?).
http://www.dynatechheaders.com/access_auger.html

jerome951

I'm comparing to the Borla XR1. The Borla is noticeably louder, but definitely not 2x. Has a more raspy tone than the Magnaflow.

Willard Bridgham 3

I don't know the cheapest, but I have data on the Fabspeed unit
w/3"test-pipe and 3" cat-back muffler. Material cost is about $1100. Joe
Fabiani makes nice stuff and it is aerodynamically very clean and all
test-pipes are not so clean.

Based on 500-600 cfm turbo:

The pressure drop from the turbo down-pipe 2.5" vs 3" is approximately 1psi (from turbo to test-pipe). 3" is what will fit here on relatively stock cars.

The difference in pressure drop between 3" and 2.5" from turbo back (test-pipe and muffler ) is approx 1.0 psi; difference between 3" and 4", same pipe, is 0.5 psig.

The pressure drop of the cat is 2.5 psi with 2.5", 3" or 4" pipe; it can be higher if the cat is plugged.

Total pressure drop decrease 2-1/2" vs 3" or 4" is approx 4.5- 5.0 psig and hp increase is significant and the turbo spools quicker.

I have no financial interest in Fabspeed and ordered his stuff after
looking at what else was available.

Chris@Fabspeed

We used to offer 4" systems (Cat back), but they did not sell well. We still have all the brackets to make the systems.

While our current offerings are great, I just picked up a 944 Turbo myself, so you can bet I will be doing a lot of development on it on the parts that we don't make already (header, crossover). I will play around with muffler setups as well.

stuttgart46

For those of you that are not running cats, how bad is the gas smell in cabin? I haven't run a 944 w/out but my 911's and 914's were awful for street driving. I always smelled like I just mowed the yard.