[Mk2] [NA] V6 Exhaust with supercar style bypass valve.

[Torero]

Now for some pretty awesome exhaust work.

Please check this out in more detail on my build thread on TwoBrutal http://www.twobrutal.co.uk/forum/showth ... t=vendetta"] It gives a bit more background information on the down pipe fabricaton as well but this is worth sharing for the home builders and IMOCers to read on it's own.

I love listening to the sound of the supercars driving around London, the specific note they give is often a result of the bypass valves that open up when you thrash the loud pedal from low revs. The valve allows exhaust gasses to by pass the back box and gives free flowing thrust through the tail pipes, hence 4 tail pipes on the more exotic cars. The net result is extra thrust and a trouser wetting roar that is very distinctive to each marque. So I managed to get an automatic butterfly valve from eBay complete with electronic controller and Patrick (Headcase) came up with a perfect design which he fabbed up using a tubby back box.

This is a shot of the valve in place, as you can see the actuator is at the base and the y pipe traverses the back box at the top but when the valve is shut, the gases run straight through the muffler. This is also a good image of the electronic actuator as well.



...and other side.



This is how the outgoing valve end is seam welded into the tail pipe.



...and another angle.



The sound is pretty amazing and the amount the valve can be opened is regulated so it can be remotely operated to 'tune' the sound a little louder or quieter. Even though this is a quieter one than the Fujitsubo we removed (and I must admit I loved the sound on that but when the down pipe was failing it was way too loud), it still slightly louder than stock as normally the Turbo muffles part of the sound but the growl from a standing start is quality and not the usual 'Boy Racer' drainpipe style boom that I dislike so much, it is much more in line with that supercar sound.

The old Fujitsubo Jasma ..... I really did like this.





Brian (BriWeekes) also has one fitted on his Ferrari rep with a bigger exhaust for more effect but I'm thrilled with this and the engine powers me so much more smoothly and quietly......until I open the valve of course. TBH you couldn't drive for long with it open but it's so cool off the mark.

I'll add some more shots and a vdeo a little later on.

[Martin F]

Awesome , It's great when you come up with a new project , put it into practice and get results like this, looking forward to the video, well done to all involved

[Torero]

Thanks Martin there are plans to get the valve automated by using the TVIS VSV signal but that's a future ambition and was pointless until we'd proved the concept.

With the dark nights and me working weekends presently, it's been a bit difficult to get the vid sorted but I'll see what I can do this weekend.

John.

[synXero]

using the TVIS VSV signal but that's a future ambition and was pointless until we'd proved the concept.

I looked into this once on an old 3S-GE car. Decided it sounded too silly 'straight through' so binned the plan. On a V6 I imagine it will sound much more acceptable! Read about this on TwoBrutal and it all sounds excellent, again can't wait for vid.

[Super_red]

I was thinking of doing this on my twin setup, having one of them switched off at low RPM's should make it quieter but both pipes would still be silenced. I was also going to use the T VIS system to activate it as this should be pretty simple and at the correct RPM's youd want it.

I didnt bother in the end as I thought fitting all those connections in the middle of a twin system would just fall appart, the way you have it is much stronger.

[Torero]

Thanks mate, I was looking at fitting 2 valves (one to each downpipe) until Pat came up with this design. Fingers crossed I can get it sorted with the TVIS VSV signal fairly soon, now the concept has been proven.