Exhaust experts

bigfatmat1, Sep 23, 9:41am
I have a car with 3 mufflers a large center one and one each side at the rear. Its a 07gtb legacy. Where does most the silencing come from? Center ? Rear? It's to loud for me. it has a stainless cat back exhaust system. I am getting a new computer map next week and would like to keep the high flow just less noise. Ideas?
nick91111, Sep 23, 10:52am
What diameter? You could try smaller rear mufflers, as they really lower the noise a lot, and/or add resonator(s) to the rear pipe(s). There are good smaller sized sports type mufflers around that are free-flowing with good performance but quiet (and not big canon size).
tweake, Sep 23, 10:56am
ideally need to have a look at the internals.
i would guess the rears are probably more like resonates than mufflers, so changing those will quiet things down.
but be careful not to make the rears to restrictive. you can get an effect where it will run fine at cruise but soon as you boot it, ie overtake someone, the end of the exhaust, being to restrictive, means the pipes take a little while to fill up and then the engine chokes on the back pressure. result is big drop in power right when your overtaking and a truck is oncoming. nice!

so don't go putting on tiny rear mufflers trying to quiet things down.
go a bit smaller or different design but if its still to loud change the front one as well.
bigfatmat1, Sep 23, 11:01am
I just double checked the middle looks more le a resonator and is tiny in comparison to the factory one would changing this make a difference I quite like the look of the rear ones
marte, Sep 23, 11:05am
Check to see if what you are looking at is a catylitic convertor.
bigfatmat1, Sep 23, 11:29am
No its after the cat it has had a cat back exhaust fitted.
snoopy221, Sep 23, 11:32am
bfm middle will be a straight through resonator both rears will be straight through mufflers.
Changing rears to non straight through will achieve what you want.
{straight through is one centre pipe with holes surrounded by glass fibre and an outside can}
non straight through is two pipes one in and one out-generaly identified by one pipe in at the top-or the side and one out at the other side-rather than central pipes at either end of the muffler.
snoopy221, Sep 23, 11:33am
bigfatmat1 wrote:
No its after the cat noisy houer chasin tail- lol
kazbanz, Sep 23, 8:40pm
mat-hang on a mo. You are saying the car is too loud.
is it too loud/droney for you driving or is the noise coming from the back of the car the issue?
bill-robinson, Sep 23, 8:50pm
which engine?
bigfatmat1, Sep 23, 10:57pm
Ej20y 2lt turbo
bigfatmat1, Sep 23, 10:58pm
both its illegal @96db
kazbanz, Sep 23, 11:05pm
In that case I'd be replacing the main muffler first.
lookoutas, Sep 24, 4:56am
The back ones on every Subaru that I've owned, usually control the sounds.
lookoutas, Sep 24, 6:57am
Got a guy to put a big bore on one of mine years ago. He was all smiles, telling me it was good. Paid the bill and drove off - it sounded like a bloody Iroquois!
Had to do 135 before the sound got left behind. Wasn't really a problem back then. After pounding that around the country roads, I was heading to Wellington when the muffler thankfully blew its arse, so I stopped at Palmy and got another one fitted. The guy said he knew what I wanted, and he got it perfect.
bigfatmat1, May 14, 3:08am
that's good this is way to loud sounds good. However with the single twin scroll turbo and equal length headers they have lost nearly all the rumble.