NBL

1991 964 C2 manual conversion. Just finished a three year rebuild. Everything is new…..even the case. Don’t ask!

I have the Fabspeed rsr exhaust with heat. It’s loud. Besides failing the warrant/MOT checks for excessive noise, it’s too loud to drive. I’m going deaf. And I don’t like driving around with earplugs in.

I was thinking of making up a couple of baffles and inserting them between the muffler and the tips. Used to do this with motorbikes and it worked okay.

Anyone done this or similar? Wondering also how baffles will change exhaust back pressure.

Any help appreciated.

LouZ

This is what I stated as an alternative method to add a baffle:

https://rennlist.com/forums/964-foru...vs-g-pipe.html

Post #7

964George

Check out Goughary's thread below, from post #49 is what you're looking for.

Exhaust Madness!

NBL

Thanks you both! I searched….I swear I did!

Goughary

You searched....but you didn't looooooooook....



I try to search on rennlist and get basically no answers. In fact- i usually use google to search Rennlist, which is much more successful when. I'm looking for something...particularly old madness threads which are now long buried.

Fwiw, the results post begins at post 54.

I took out some of the stainless wool recently to try something and have to say, i felt an immediate loss again in mid range and it's now louder by a fair amount. So I'll likely dive back in and play with different baffles at some point and get things back to where they were or maybe better....who knows .

Let us know what you come up with.

Goughary

Hi or did the manual conversion go. Did you have any major wiring/electrical issues to sort?

NBL

Hey Goughary

manual conversion went very well! Worked a great and looks factory under the car. Just been smashing it around the Hunua hills this afternoon and love the short shifter.

I wrote a wee book on the install with parts and instructions for anyone wanting to do the manual conversion. The manual is on the forum somewhere. Sets out all the costs too.

Just fixed the drone from the Fabspeed exhaust too. Bought baffles from Car Chemistry and jammed them into the exhaust tips. No more ear plugs!!

but….I reckon I’ve lost significant power. The throttle isn’t as responsive, and the car runs on much easier rather than having good engine breaking. Interesting.

Once I get a warrant/MOT I think I’ll cut the baffles down to find more power without going deaf!!

Goughary

Which size baffles did you buy?

You can experiment with baffling one side more than the other. If your fabspeed internally is like mine, the main pipe enters to a T and then the perforated pipe is just an open pipe to either side. So you can force the exhaust flow to one side or the other, and those pressure changes can change dramatically the back pressure and performance and also the sound and at what rpm you experience drone.

Do an experiment and just baffle the passenger side and leave the driver open, and then swap sides. You'll be surprised at how much difference there is.

I recently opened up the passenger side, a little drone came back at low rpm around 2200 and lower, but the car feels good. Still playing a little.

I'd love to read the conversion manual. I don't know they much about the tip systems and how they play in the car.

NBL

Thanks I will try that when I’ve got the warrant. I’m keen to make it slightly louder, but more keen to get the power back!

I bought the car chemistry baffles following and tapped them into the exhaust pipes just before the tips. They wedged in there and drop the sound considerably.

3 Disk Insert : 2 1/4" Diameter

3DI22R

NBL

Here is the tip to manual conversion manual again

https://www.dropbox.com/s/op89034k00...0list.pdf?dl=0

Goughary

I'm assuming you did not use the metal caps right? I used the same size for mine.., and wrapped them with very coarse stainless steel wool. Interestingly enough, i noticed a considerable increase in mid range power. Can't tell you what it did to peak hp...but the car felt much better and improved throttle response.

What Cat are you using ? Mine is a 125cell sport cat.

Fwiw, i also have a very early production fabspeed dual outlet, so i don't know whether the internals are the same from yours to mine...
Lemme know if you figure out the power drop.

NBL

No cats in mine. Will fiddle around with the baffles to see if I can find a balance between low end power and noise!

in for the warrant today, after 3 years of rebuilding…..

Mulldoon

Why not custom turn down tips that go from let’s say a 3” to 2” or similar. This is a very reasonable solution without mitigating the flow of your petrol burner.

if you don’t like the feel of the turn downs with mitigated sizing, your shop can turn them delicately and open them up.