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one or two exhausts
craigdiver - 22/4/18 at 02:34 PM

with emissions being a moving target nowadays I have given my exhaust system a rethink. Its a BMW 6 cyl and original exhaust went 6-2-1 with two cats before the 2-1.

My original plan was to take NickP’s advice and go 6-2-1 with 2” out the manifolds combining into 3” and through a 200 cell 3” sports cat to the muffler.

Would it be twice as good at reducing emissions if I went with two 2” exhaust systems down the side of the car (with 2x 2” cats and mufflers)?

Am I likely to get any deals on exhaust components at Stoneleigh next month (never been so don’t know if likely to be stall(s) selling exhaust components)

rodgling - 22/4/18 at 03:29 PM

quote:
Originally posted by craigdiver
with emissions being a moving target nowadays I have given my exhaust system a rethink. Its a BMW 6 cyl and original exhaust went 6-2-1 with two cats before the 2-1.

My original plan was to take NickP’s advice and go 6-2-1 with 2” out the manifolds combining into 3” and through a 200 cell 3” sports cat to the muffler.

Would it be twice as good at reducing emissions if I went with two 2” exhaust systems down the side of the car (with 2x 2” cats and mufflers)?

Am I likely to get any deals on exhaust components at Stoneleigh next month (never been so don’t know if likely to be stall(s) selling exhaust components)


I use a 6-2-1 system on mine, which goes into (currently) an 8" silencer (no cat), followed by a second silencer under the fuel tank to keep noise down for track use. This works well, that said emissions have always been a tricky issue, even with a can with a cat fitted. I don't think this is down to the exhaust though.

907 - 22/4/18 at 07:55 PM

I have a couple of brand new 200 cell sports cats if you are interested. 4" diameter with 4" to 2" cones.
The cones can be cut so the inlet / outlet is bigger if required.

The cells are stainless so they are more durable than cats with ceramic internals. (the ones that rattle when they break up)


£180 the pair + P&P at cost


Cats work better the nearer they are to the engine as they need to get hot.



Paul G

stainless cats
stainless cats