Thanks for input.

To bad Swedish Goverment deos not allowed 100 Cell, you can buy them, but the chance is that they give you a fine, or it will not pass the Official car test, every Swedish car MUST doo every year.

In my dreams my mufflers sounds like the Fister Stage II..

Thats the nicest sound I heard yet.

 

Interesting thread minus the negativity of some of the post.

We had this same type of thread when someone created an exhaust system for RS4 in the Audi world. PPL claimed it was a copy of another exhaust...bc it looked the same in the end the so called copy did not sell well and the one that was supposedly the originator sold a good amount.

But there was back and forth on who was the originator of things like an X-pipe for the exhaust system or who first designed the exhaust to use 2.75" tubing and the original company was not even the two being compared.

I think the thread is interesting bc it give us novices insight to how to modify the muffler.

I have a spare set of mufflers for my 993 and will either go Fister III or do it myself, depends on how much time I have or if I want to even do it.

Thanks to all who posted some interesting information regarding the 993 exhaust.

 

Here's my take on the 993 mufflers; Quiet when needed (certain local tracks with db limits, annual inspection, sitting in the stop light next to a police car etc. you name it), other times LOUD AS HELL!!! All this with a push of a button from the cabin.

The valve is fitted to test the fitment in the car; it fit well so next we will weld the bypass pipe in between the inlet and outlet to the muffler.

 

Juha, do you have any pics of how it looks inside?

Going to weld my own mufflers this week.

I did it once like the pic below, and filled it with "cotton", but the result was almost like a stock muffler.

Think I will never be satisfied with that...soo I decided to open them up again..

Would like to ge SOME input (pics) from someone, but it seem to be the Holy Graal among 993 owners, and very few show inside pics.

Why?

The idea I have now is the get rid of all the pipes with hole and use straith pipes, and then fill the muffler with "cotton" so you prevent horrible resonance inside the coupé.

****, my school english is crappy...hope you can understand what it write..

Regards, the Swede who lives a few minutes from The Arctic Circle and have only a few short month to drive my car..

 

I don't but it's a 100% stock muffler. There will be an external bypass pipe between the inlet and outlet pipes (the valve you see is in the middle of where the pipe will be). So it will completely bypass the muffler when the valve is open.
Allthough the valve can be driven to any position between fully closed and fully open to find the best sound.

I also have a set of RSR cans but with the 200-cell cats, my car is too loud for Ahvenisto and Motopark tracks. So stock mufflers with bypass is the way to go.

 

Very cool solution. You'll have Fister Stage I / LPMM cans on demand.

But the muffler will not be completely bypassed (IMO) - some gases will exit via the bypass and some via the stock route.


Andreas

 

Yes, that's true! The gas will find the easiest way out so naturally some of it will go trough the muffler as well.
Is the bypass pipe in Fister stg 1 as big as the inlet/outlet pipes?
If that is stg1 then what is stage 2 and 3?

 

The Stage I bypass pipe appears to be the same size as the inlet/outlet pipes (+/- a few mm). Not sure of the ingredient list for Stage I or Stage II cans.

I'm on my second set of Stage I cans and love the sound.


Andreas

 

I use 2" stainless on my Stage I. Stage II has the external 2" bypass as well as some internal modifications as well. Stage III has no external bypass and is completely repiped inside.

 

I would suggest leaving the muffler as you have it now and welding in a 2" bypass pipe between the inlet and outlet. I think this will give you good results.

 

SUPER thanks Darin.

I will probably end up with the Fister Stage II, but I am that kind of guy who just got to try first on my own..

Don´t know why, just the way I do things.

But just because you respectfully helped me out (and our word is really important to me) shows me and everybody else what a great man you are, things like that really gets to me..

And I think I will buy FS II just because you are such a nice guy!!!

 

Sooooooo. Thread dig. Anyone still around? I've already got a second muffler set and am in Australia so would like to attempt to mod mine. If I had my time again I'd probably just buy a set of Fister IIs but you live and learn. Local feedback is these sound great so I'd like to replicate the sound and avoid the drone. I'm going to stop short of asking directly for the secret sauce recipe, but are the instructions on P1 right for achieving roughly the sound of the FIIs? Including leaving all the wool / baffling out of the cans?

Thanks from Down Under.

 

I did not read all the posts. The first few frustrated me enough, and frankly i felt a wee bit embarrased to be part of this forum knowing there were folks that would treat this guy the way they have.

You are fussing over what you call ip on a muffler. Even if he had never spoke with darin, he would have likely tried not replacing the stuffing or running straight through. Its a muffler and the degrees of freedom for alteration can be fully explored in only a few iterations because its a simple device. Have a look for patents on mufflers. There arent many.

Furthermore consider the humble hamburger or pizza. There is always a new hamburger shop opening up. They all sell the same thing and arent we all better off for it? So fister has a bit competition now. I am sure he has seen it before and survived. I am sure he will see it again. If you think that his success is driven by one product and one wee little idea you are not giving him the credit he deserves. Getting to where he involves a lot more than the trivial decisions involved here.

 

If you can install/reinstall, I would start with just the by pass and see how it sounds. Least amount of welding needed. I was thinking of just doing the bypass and see what it does before opening up the whole muffler. (I don't think I would cut around either. I think I would make an 'I' cut and open up the flaps).

 

I have probably messed with my exhaust more than anyone here, other than Darin or Fabspeed...
I have yet to hear a better sounding exhaust than the Stage III Fister's.

First Attempt: gutted OEM Mufflers with 2.50" exhaust with an X-pipe and 200 Cell Cats.
Results: Very deep smooth sound, much like a newer Mustang. No burble, noticeable lack of low end power. Terrible drone between 2000-3000 rpms.



2nd Attempt: 2.50" Straight Pipes with a small crossover tube for the O2 Sensor. 200 Cell Cats. The mufflers were custom made with 2.50" internals. The perforated tube was wrapped and then the muffler was packed with Basalt.
Results: Better than the X-Pipe. Even deeper sound, still no burble. Low end power was better than the first setup but I wasn't happy. Still sounded like a V8 and not a Porsche.






4th, 5th... nth attempts: I kept modifying the above to setups, changing and modifying things, swapping between mufflers and hacking / welding on things.

Last Attempt: 2.25" tubing, no crossover, and 100 cell cats. Back to the modified stock mufflers.
Results: This is my favorite setup so far. Burble is back and very crackly off throttle, the car runs great and it sounds like a Porsche again. The tone is still a little on the deep side, but it's geed enough for me.



I had one more design intended which I just never finished. This was a one-off muffler I made with 2.25" internal perforated tubes, and an air chamber at the top. The transitions to the top were radiused. The perforated tube was wrapped with steel wool and stuffed with basalt. The reason for the air chamber is it cancels out the "drone" and is why Porsche had that separate plate in there to begin with. These are still just sitting in my garage... waiting.