Well had the impreza for a couple of weeks. Wife not to happy about how loud it is... Roger Clarke GT Spec equal length manifold, up-pipes Full Mongoose 3 inch, No Cats etc

Personally I like the sound but I can see the wife's point and I've noticed a few neighbours not looking too happy about it too.

It's a 2.1 engine with a lot of stuff done to it running around 420 bhp. What can I do to quieten it down a bit. I spoke to the previous owner and he said not to fit an exhaust bung (even if I could find one to fit the Mongoose 5 inch tail pipe as it would cause problems with the running of the car???

Anyone got any sensible suggestions on what I can do. If I were to replace the exhaust with a more silenced one, I'm guessing I'd loose power so that's not ideal...

 

Not necessarily, fitting a decent sports cat will lower noise a bit without any significant drop in power. Same with a well designed silencer.

 

Any suggestions on a quieter 3 inch bore rear silencer?
To be honest, I'd prefer something with a 4 inch tail pipe instead of the Mongoose 5 inch as it's a bit over the top...
Thanks.

 

fit a revolution system, or a Milltek system. They are on the quieter side but still good for power

 

Am I correct in my thinking that by switching to a different brand of exhaust, provided I keep to the same centre bore, I should be fine with the cars current state of tune and mapping?

Thanks

 

Yup, you'll only really want to get the map checked if you put a cat in it.

 

Resonator boxes or lack of make the world of difference. I'm running full decat and a one piece fujitsubo giken system. It passes noise testing at track days, IRC 94db @ 5k rpm.
The build quality is excellent. One piece from the down pipe and an almost straight run with no bends towards the back box.. It still burbles and sets of the occasional car alarm but by subaru standards its quite civilised.

 

I'm having the same problem. Previous owner Fitted a Cobra 3'' decat turbo back and it's crazy loud. I replaced the back box with a 3'' Milltek and that's helped quieten it down a fair bit but still to much for me. So I'm having a large centre resonator fitted next month to see if that helps.
Also had to rotate the exhaust flange to get the Milltek to fit as they don't want people using there exhaust with other systems.

 

Is that a 3 inch bore system?
How much do they cost and where do you get them from?
Thanks.

 

Not sure on the size I think it's 2.5 at the join until 3". I'll have a measure up tomorrow. They come up for sale second hand now and then. Never seen a new one for sale in the uk.