What the hell is he talking about you may ask.
I was at a car salvage yard on the weekend, and spotted a MG ZR. My mate said it was one of the faster ones a 180 model.
It had the rear bumper missing, and I noticed an actuator on one of the tailpipes, it had a twin set up. I've never seen this before, and should have taken a picture.

Any one seen/heard of this before? Whats it for, noise restrictions? Couldn't find much about it on the net.


Took a picture:

 

What do you mean twin setup?

The ZRs were 160bhp IIRC.

 

Some modern cars have a valve in the exhaust to allow for a better flow rate at high revs, its some loop hole in sound/emissions limits becuase they are only tested to a certain point.

 

This is probably like the MGTF I had. It has a valve to close off one of the pipes when driving at low revs (under 3K) and its only purpose was to reduce noise.

 

It was definatley a ZR, maybe not a 180 then.
By twin, I meant two tailpipes from one box, like a standard UK Turbo exhaust.
Simog that must be it. I've never seen that before. Is it pressure controlled or electronic?

 

Dont some Porsche's have the same kind of thing?

 

some BMW's do and I've seen the new Corvette with it too

 

BMWs do.

Noted a brand new 535d with one on the right-most tailpipe. As it was new you could clearly see it, as it had yet to carbon up.

Probably a by-pass for the baffles in the rear box. Shut at low revs/speed for to pass noise emissions, opens up at revs to give the driver more "aural" satisfaction. And maybe give 2bhp more power - if your lucky Or if you belive the marketing boys - 20bhp extra

My 325 touring has one...apart from it appears to have broken and is stuck open....always wondered why it sounded a bit more rorty than other 6pot beamers.

Ferarri was one of the main cars to baost about them being fitted

 

All correct. Main purpose is for noise control.

 

Took a picture of it the weekend after (what a geek).
Added to first post.