Alpinweiss exhaust v.3

[Error404]

Best option would be Sytem E with a TPS mapped butterfly valve which is how the modern supercars with active exhausts do it

[A80Avant]

It's interesting. I hoped to also have something similar for egt reasons mainly rather than loudness.

[Nimz]

It's got to be Option E IMO Andy...option D only if E would be too loud


Nimz - Pearlescent white 1992 S2

[Greg_S]

def option E

[Zoig]

System A for me,

building loads of big power jap cars with exhaust butterflys previously i know what this setup is capable of.

dont cut the bumper, just point it to the floor before the bumper, thus better on sound reduction also

That modification to A would be my option, should be a bit easier and lighter than D or E

[re2500]

I like the simplicity of E and like the idea of each tailpipe having its own job.
My only worry would be space behind the rear subframe, i dont know about you but i have a tight P shape in my system before it enters the backbox?
My system looks like this and is quite tight in that area so i dont know if what you might need is a Y before the backbox and valve? Will try and illustrate...

[Rusty]

I know what you mean. It's pretty tight for sure. Option A does work well there and I can run a small back box with a centre box too. Lots of options; I guess that the best solution will only present itself when I look at it all on the car...

[re2500]

Yeah you wnot know for sure until you look underneath, i suspect a really small cherry bomb type silencer might work quite well at the back, maybe even slightly diagonally to ruduce the bends??
... my illustrations of the shape of my current system first, then what you could do to keep a fairly large backbox, and lastly what i think would work and sound the best. This design has a small backbox with very few obstructions, the long dead end length before the valve would really help two fold, reduce resonance when the valve is closed, and also help to keep the valve cool if you want to use it in anger and also there is plenty of space here for it...

[Rusty]

Aye, that's the sort of thing. Basically, I want to get rid of the valve under the passenger seats and move it to the rear. It would also be nice to have a bit more noise as stock. A Yr pipe at the junction is totally acceptable, perhaps with a 3" and 2.5" circuit. I want to keep the 2.5" section to reduce resonance at cuise.

I have to say, I think the sound check at Combe is very harsh. My car, in it's current configuration has never tested over 90dB and is usually 88dB and they said that it was 94dB! I'm fairly convinced that the proximity of the shed to the sound test area throws the numbers up. 4-6dB is not a small amount, so it's not going to be as a result of wear and tear.

[Sonic]

I'd like to think you could use A, but with an M5 style quad-exhaust system protruding from the rear.

That way you could make the rear-bumper hole the same as the first and keep a stock system with just another 2x 2.5-3" pipes welded on before the back-box

[re2500]

Totally agree mate, the valve has plenty of space where it is at the moment but there are quite a few advantages of having it at the rear. I also think the 2.5" rear section works very well, as you know my exhaust is similar from that respect and it does keep it rather civilised when cruising.
Yeah the combe check was harsh! even though i didnt go out in the end i should have had a sound check myself. It would have been interesting to compare, being that the only exhaust difference valve closed is that i have no cat. It think there were a few cars last weekend that probably read over the limits when perhaps they shouldn't have..

[re2500]

I'd like to think you could use A, but with an M5 style quad-exhaust system protruding from the rear.

That way you could make the rear-bumper hole the same as the first and keep a stock system with just another 2x 2.5-3" pipes welded on before the back-box

Yeah, and map the valve to cut in at high boost.
Or ive often thought that you could use a mechanical valve from a turbocharger that has a built in DV actuator (ive heard you can use one off a discovery) and make a linkage to open the valve at 1.0 bar or something?

[Sonic]

Come on Rusty, how awesome does this look?!?!

[Rusty]

It wouldn't look like that though, it would look like the OE on one side and like someone had cut a hole on the other...

I did think about getting my design hat on and making some surrounds to blank the exhaust hole one side and make it matching on the other with 2x 3" pipes.

I've seem pics of cut bumpers and they're just not as good as the properly finished OE hole.

[Rusty]

Of course, there's always the 90’s DTM quad upswept option