well before i go back to epa test, exhaust needs to end just after the rear of the car.

so i need to extend it 35cm- easy but i also need to quiten it from 100.4 db to 96 or less.

Now i have a stabdard subaru center hotdog muffler that is 2.25 inch piping (stock suby wrx part) but 30cm long and i doubt if i left it 2.25inch it would read less than 96db.

any suggestions on how to legally reduce the db whilst retaining the rest of the 2.25 exhaust.

Currently has 1 center muffler.

I thought if i could get a commodore center muffler (you know the small ones, i think they are about 20cmin length) and then put a 2 inch or similar pipe as the tail pipe, it might just squeeze under 96 db.

help anyone, and where to get one of those muffler cheap cheap cheap. thanks

better center muffler, or add a semi offset muffler to the rear.

ive got some 2.25inch mufflers from my previous exhaust setup, might do the trick

just flange either side of the muffler and put a quieter one in. the one in there is an offset straight through muffler so you could get an actual baffled one and it should do the job easy enough

A little off topic but on the notion of legality, does anyone know anything about side exit systems? Obviously alot of older rods are registered with them, are they legal if you make it under db limit? As far as I know the rule is just after the furthest Point of the last door, or just after the diff

600mm (i think) behind the rear most opening. has to meet noise and height regs obviously

side exhaust is a no no on the sedans, coupes and wagons, needs to be certain distance past the rear most opening (door or window etc), and protrude for the body by at least 40mm at the rear most point.

on a side note, think i might go to wreckers to source a couple of cheap mufflers if no one has or can find a holden v8 centre muffler, you know the tiny little ones in the middle of the car. not huge but might be engough to get it down to 96.
see in pic, like the little round hot gos just after the center muffler.

I have two sections of pipe that fit together ( one inside the other) tightly and can be inserted into the tail pipe with force, this reduces my exhaust ID to about 30mm.
After rego I'll cut off the affected tail pipe and replace it.
Reduces Hp aswell so all good for the pits!

does it reduce the noise/db sound levels too? good idea as a temp measure til i get something more permanent.
Just have to swap in new seat belt, get rev switch working, and tie rod rubber seals, and its ready. should be ready for RWC too then.

I just checked the ID of the smallest pipe and its only 25mm.
The two smaller pipes are not a tight fit in the exhaust that I have, they simply get jammed with force into the rear most bend in the exhaust system, this might give it an unhealthy sound and raise questions at the Pits so stuff some steel wool in there to muffle the sound.
Thats my plan anyway, quiet and not too powerful to raise questions ;)

Mates RX3 has a massive 2nd hand muffler from some unknown large engined car on a flange right at the rear of the car.

Anytime it has to go over the pits he puts it on and then swaps it straight back out for a straight thru tailpipe when he gets home

Dead quiet (well for a rotor it is ) when required and quick and easy to swap..