Stummel

Finally I found a manufacturer of custom made hi-quality mufflers with bypass feature. Do not know how you call it but it is a muffler with a bypass option that you control from inside the car with a switch.
You can configure the sound even after you installed the muffler.

They even give us TUeV on that one!!!

I am in contact to get a price quote.

Anyone interested? Group buy?

They also make bypass mufflers for 996tt, gt3, boxster...

Kevin

The concept looks good.. However, the diameter of the pipe look small >60mm

Felix

yes dependent upon cost and sound

Stummel

They also make bigger custom pipes for hi hp-cars.

Lets wait for the price...

TB993tt

I always liked the concept. Big problem on the turbo exhaust I thought was the extra heat and pressure involved caused early bypass valve failure. Has this manufacturer had a system working on a tt for any length of time, through a winter ?
If it could be made with the big 60mm piping and made effectively like a muffer bypass when in "open" mode that is good - I would be concerned about the sound quality in closed mode. Will it drone etc.
Probably a bit spoilt with the C/G race muffler set up which is loud outside but perfect in the car and no droning at all.

leonsamonas

doesnt look very special to me either....

viperbob

I don't like the design. For a turbo, you really won't gain much in terms of sound or HP. If you look where the valve is, all it is going to do is open up, and lead the exhaust around the muffler instead of forcing it to flow out some holes in the pipe on the inside of the muffler. Sound flows in waves on the outside of the pipe, so if it is open the waves will still be partially absorbed by the muffler. So what should a bypass pipe do? Bypass the muffler. With this design you have the worst of most worlds. Small pipe, LONG travel (this is a killer for a turbo car. You wnat a short a travel out the turbo as possible), and more bends. The best design it to put the bypass RIGHT WHERE THE INLET AND OUTLET MEET OUTSIDE THE MUFFLER.

Stummel

Bob,

I have a soundfile of their 996tt bypass muffler and it sounds OK a bit like my 993tt with FVD muffler bypass but not that extreme.

I will talk to the guys and hear why they designed it that way. Perhaps they want to be able to get TUeV for their customers?
I also think that a real muffler bypass will be better in performance.

But for the people that can not live with a full bypass this might be a solution.

Even on the Nuerburg-Ring you can run into issues if the car is too loud, so this could work.

The coolest bypass would be just before the cats but I doubt that the valve will work for longer periods of time at that place.

ttAmerica RoadsterAWD

This is similar to what Ferrari does to their newer cars. The F430 and I think the F360 have a valve just prior to entering the muffler and directs the exhaust energy straight out the exhaust tip, effectively bypassing the muffler. I was able to speak with the Ferrari guy I "raced" a few weeks ago and was surprised at how quiet it sounds while at idle-almost too comically quiet. Apparently when the vacuum goes low, when he floors the gas pedal, it somehow activates the bypass route and you get a completely louder and less restrictive sound.

This would be a good idea to have when just puttering around town in cruise mode, yet loud and determined when the heat is on. I was thinking of rigging something like this for my car....along with alot of other stuff I'd like to invent.

Jaime

Red rooster

Those look like the valves on a Golf 4 Motion/RS4 ?

Geoff

Jean

Stummel

I am very interested in the mechanism, not the mufflers themselves. I had been looking for something like this for a while before going to the 'Ring. At the end I just had to weld closed one side of my exhaust to reduce the sound and I hate having to compromise both sound and performance.
If the mechanism can be bought separately it would be great.!
I heard a 996TT with a 9FF exhaust with this system, and the difference in sound is absolutely fantastic. The price also.

Red rooster

Jean,
Find a company doing replacement , performance exhausts on VW/Audi , then look at what they are taking off ! VAG introduced this bypass system a few years back on performance models. Problem is the valves are part of the exhaust so have to be hacksawed off !! Vaccum driven ,all stainless steel - very nice .
The pipe diameters will be an issue for you but at least you would have parts or could identify the manufacturer .
I got a pair from a big UK ,VAG tuners scrap exhaust pile ,for a mate who wanted to do the noise thing !!!

Hope that may be useful

Geoff

Jean

Geoff,

It sounds like a very good idea. Where I live things are not so simple to find I could get a 996 Carrera exhaust sound package that has a similar setup but it is very expensive for what I need it. I thought those kits could be found somewhere as a standalone.
I will look into it. Thanks,
Jean

sonny1

Jean, amigo,
I have alredy done this in a BMW,this is the place to go for the valves:
www.atpturbo.com
it is called "Virtual Exhaust System", scroll down their home page,it is right there.,cheers,Sonny.

ttAmerica RoadsterAWD

sonny, thank you very much for this tip! If they have an appropriate diameter for our cars, I'll do one up.

Jaime