Quote Originally Posted by Chris_F View Post
Replacing the stock exhaust with a dual outlet exhaust has minimal gains on a stock standard car with no ecu tuning. Maybe a few hp if you're lucky.

But your car is far from standard and, with the reflashed ECU, I have a feeling the stock exhaust might be holding you back a little (hard to know without dyno testing). If you want to maximise your gains, single outlet 2.5" to 3" exhausts are proven to work well with modified k series engines. A good exhaust shop will be able to make you a 2.5" single outlet exhaust, 1 resonator (good brand like magnaflow), 1 muffler (good brand like magnaflow) and mandrel bent stainless steel piping for about $1k.

But if you want to keep the dual outlet look of the exhaust you'll be looking at a few hundred more if you go custom. There's also plenty of aftermarket options from Japan and the US. But with the Aussie dollar the way it is at the moment though your going to be paying more than usual.

I'm keen to see a new dyno for your car!
I think our stock exhaust is 57mm. ( about 2.25 inch). Id love to try a 2.5 single custom system but theres a few people here ( Junyu I think) who tried this and got a lot of noise and resonance and I cant stand that. Im totally happy witht he amount of noise my car generates for the power at the moment. So I would do it but dunno if i can take any rice droning.

That being said, the 06-08TSX went to a 62.5mm exhaust and that was after a small power increase of about 7kw I think.
So it must be worth it as 62mm is about 2.5 inch.

My last dyno was 118kw and normal euros were about 102kw ( on that dyno) so im up about 15kw, plus my latest mods Im guessing around 125kwatw now easy.

So gieven honda upped the exhaust for 7kw, i may be hitting the limit for the 57mm exhaust.

Hard to say...