Rear muffler - essential??

[MasterOfReality]

When I got my exhaust done, the guys told me that I must have a rear muffler otherwise I'll get defected.

The system I got put on was a twin cat 2.5", merge into 2.5" resonator, into rear muffler and 3" out.

This absolutely droned like a bitch so i cut the resonator out (which was positioned under the back seat) and now most of the drone is gone and the exhaust has a lot of bark to it.

Now my mate had a vl calais with a vs senator motor in it, and he had a single 2.5" inch into a intermediate muffler then into a resonator and tip at the rear, and it was one of the best sounding exhausts I have ever heard.

So, were the guys at the exhaust shop full of crap?

Can I get rid of the rear muffler, replace it with a resonator and put an intermediate muffler in without being defected???

Thanks guys.

[Not_An_Abba_Fan]

I'm not sure about the regulations in the state you are in but generally you need to have the same amount of mufflers in the same positions as factory. Most people will get away with it, but it pays to have a spare stock system in the shed to put on for RWC's.

[les82]

it pretty much comes downs to the DB output of the exhaust

[Morton]

A muffler, a hotdog, a cherrybomb, whatever you call them - they're all resonators. And I know for a fact that in Victoria, your vehicle must have the same number of these that it had from the factory. The Commodore had two resonators from factory, and SHOULD have two at all times... let's be honest, I think 99.9% of the time you'll get away with having one, and everyone does. But in strictly legal terms, you should have two.

If you're keen on the sound you get from the use of just one resonator, then perhaps look into having a dummy muffler shell welded on around your straight pipe. My mate Michael has a straight-through 3" turbo-back exhaust on his VL with no resonators at all - just two shells welded on and a fake cat... and he's never had a problem with the authorities. (he's also running 3 bar boost and half a dozen other sans-engineers mods, but that's not the point!)

But yes, you will require two for a roadworthy - my car was picked up on this point when I purchased it.

[Not_An_Abba_Fan]

A muffler is a muffler and a resonator is a resonator. The correct term is a silencer not a muffler. The internal design acts to 'bounce' the sound waves back into the oncoming ones so that they cancel each other out. A resonator is straight through and it's job is to take out certain frequencies in the sound waves to reduce harmonic resonance or 'droning'. If you would like me to go into the finer details I can but most readers would find it boring as batsh**.

[MasterOfReality]

I can't even remember what my stock hsv exhaust system looked like, although I remember it had a single cat and may have branched off into two mufflers before rejoining at the rear muffler.

As it stands now, i have 2 cats and only one muffler.

I might ask the exhaust place on monday.

[coolvxss]

Mine only has one muffler and no ressie, But i still have my ressie in back shed incase i ever do have to put it back on. But i have been pulled over many times without a problem YET.