Ok i'll keep the cat, can i get rid of the muffler?

[Daniel.B]

So i'll keep the cat converter so my children don't grow up deformed, and so my wife will steer clear of the friendly neighbour who drives a hybrid, can i remove the muffler and just have a straight pipe, or can i just dump the exhaust off before the diff( assuming i dump it downwards away from the petrol tank) I'm just after away to build a performance exhaust myself without having to visit an exhaust centre. I've been told hi flow cats are a waste of time on a v6- is this the case?

[danja]

There is a legal limit on noise (90dB in most states I think?), if it's earth shakingly loud you can expect police attention and potentially defect notices, most people usually get away with going a little over that limit, but basically if the police can tell you've departed from stock they can potentially defect and fine you. The more you go over, the more likely someone is to take notice.

As for how to do it, you could replace the mufflers with hotdog mufflers (which are pretty much a straight through pipe with a bit of sound baffling) or you could use a straight through performance muffler, there are some which give half-decent muffling without being restrictive.

You can always just go and talk to some muffler shops for ideas, then once you think you know what you want, just buy the parts and fit them yourself.

[Andrew426]

You can only dump near the diff if its 40cm behind the last perminently welded or sealed join in the floorpan. Basically that means, you can only do it if you have a ute.

[Daniel.B]

I'm happy to risk the defect, i know it will be loud, but would it be constantly loud, or just under acceleration? Why are there 2 mufflers, one half way and one at the end? can i end the exhaust at the first muffler, if i did, what would i need to replace? would i need a larger diamater pipe between the cat convertor and the first muffler, and what about the 2 into 1 piece before the cat convertor. Are there noticible gains to be had by removing that last muffler and 2 odd feet of piping that go with it? Thanks to anyone helping me so far-

[89 vn]

Law states car must have at least the same mufflers as fitted from factory, so I believe a VN/P has 1, and if this is a V6 please do us all a favour and dont make it a droning annoying exhaust

[danja]

I'm happy to risk the defect, i know it will be loud, but would it be constantly loud, or just under acceleration?

Depends on the setup. Some drone, some don't. Talk to an exhaust shop - tell them what you want and see what they'd recommend.

As for where you end the exhaust, i wouldn't do it anywhere except at the end of the car. Exhaust gases are HOT and they will cause damage if they end up in the wrong place. I've put out an underbody fire on a car that started from the exhaust. It does happen.

[Andrew426]

Instead of losing all your mufflers, keep the front one and replace the big resinator at the back with a hotdog. And you will see sod all performance gains from losing only the last few feet of pipe.

[padrickz88]

yes you can get rid of your muffler.... im going to be doing the same when i can be bothered

and it should make it louder......

the reason they have 2 mufflers is to keep the noise down obviously.... they have epa restrictions that they need to stick to......

[greenfoam]

Two straight through mufflers is what you want, no restriction and not much noise (unless you boot it)

[Daniel.B]

I've had another look underneath, where the 1st mufflet exits, it's quite far from the petrol tank, which is why i thought i could end it there. I also thought it would be less restirctive as it has less distance to travel before finally exiting. Thought it would be cheaper to cause i wouldnt have to pay for the rear section of pipe and muffler and tip-

[Morton]

You can do whatever the hell you want, mate. But here are the legal requirements - and yes, you're free to ignore them:

1) you must have the same number of mufflers/resonators on the car as factory - in this case, two.
2) you must not exceed 90db of noise from the tailpipe
3) the exhaust must be sealed right up to, and exit behind, the last unwelded open cabin space - in your case, the boot.

So no you shouldn't dump it anywhere before the rear bumper, no you shouldn't have less than two mufflers, and no you shouldn't make it freakin loud.

But you're more than welcome to if you want to be a fully sick maverick. Cutting the exhaust off at the headers won't give you any extra power, and making it louder doesn't make it really really good.

Now go hollow out that catalytic converter. Go on. You know you want to.

[danja]

You can do whatever the hell you want, mate. But here are the legal requirements - and yes, you're free to ignore them:

1) you must have the same number of mufflers/resonators on the car as factory - in this case, two.
2) you must not exceed 90db of noise from the tailpipe
3) the exhaust must be sealed right up to, and exit behind, the last unwelded open cabin space - in your case, the boot.

So no you shouldn't dump it anywhere before the rear bumper, no you shouldn't have less than two mufflers, and no you shouldn't make it freakin loud.

But you're more than welcome to if you want to be a fully sick maverick. Cutting the exhaust off at the headers won't give you any extra power, and making it louder doesn't make it really really good.

Now go hollow out that catalytic converter. Go on. You know you want to.

I was going to rep you, but I have to spread the love. I rep you in spirit

[Daniel.B]

Ha ha, yeah i've been told i can use the end of a broom handle to smash all the inside out of the catalytic convertor- are headers the 2 into 1 piece just before the 1st muffler? What's the second peice just before the rear muffler, like a giant piece of intertwined mesh- Morton, i don't want it FREAKN loud, i don't want you to be able to hear me from melbourne- just a nice noise that's all- just seems all the old cars in the past used to run a similar set up as to what i had in mind, particulary race cars- yes i know its not a race, it's a family orientated 4 door 5 seater sedan.........

[Daniel.B]

what does that guy mean by rep me?

[Morton]

I was going to rep you, but I have to spread the love. I rep you in spirit

hahaha cheers mate Thankyou. In spirit, of course

[Morton]

Ha ha, yeah i've been told i can use the end of a broom handle to smash all the inside out of the catalytic convertor- are headers the 2 into 1 piece just before the 1st muffler? What's the second peice just before the rear muffler, like a giant piece of intertwined mesh- Morton, i don't want it FREAKN loud, i don't want you to be able to hear me from melbourne- just a nice noise that's all- just seems all the old cars in the past used to run a similar set up as to what i had in mind, particulary race cars- yes i know its not a race, it's a family orientated 4 door 5 seater sedan.........

If you want a nice noise, try a single glasspack muffler for the centre piece, and a hotdog three-quarters of the way back. Something like a SuperCat muffler will give you a nice noise.

[Daniel.B]

how much would i be looking at for this?-roughly

[Morton]

$200? . . . . .

[danja]

$200 bucks off eBay?
COMMODORE VP VR VS VT VU VX VY 3.8V6 EXHAUST SYSTEM - eBay Full Systems, Exhausts, Car Parts, Accessories, Cars, Bikes, Boats. (end time 06-Mar-09 11:38:53 AEDST)

[Daniel.B]

checked out the ebay add aparently they ony fit IRS version...? i'll just visit an exhaust shop and see what i can pick up

[danja]

VN VP VR V6 SOLID AXLE SEDAN 2.5" CATBACK EXHAUST - eBay, Other Car Parts, Accessories, Car Parts, Accessories, Cars, Bikes, Boats. (end time 01-Mar-09 20:23:38 AEDST)
Commodore VN VP VR VS V8 3 Inch Sports Exhaust-Live Axl - eBay Full Systems, Exhausts, Car Parts, Accessories, Cars, Bikes, Boats. (end time 05-Mar-09 19:01:00 AEDST)
Holden Commodore VN VP VR V6 Sedan Sports Exhaust - eBay Full Systems, Exhausts, Car Parts, Accessories, Cars, Bikes, Boats. (end time 05-Mar-09 19:10:16 AEDST)

For live axle VP's.

Search dude, it's all out there.

[jetspin_vn]

Why god why do people insist on butchering standard exhausts in search of a third of a horsepower?!? Do yourself and your car a favour, if you have a hundred bucks sitting around this week and are thinking about hacking a muffler out, perhaps wait a month or two till you have a few MORE hundreds sitting around, and then do it properly!

And by properly I mean headers back. If I have to listen to another 6 into 1 into 1.5" into fart cannon exhaust today, I will hurt someone.

Your driving Commodores kids, the Generals pride and joy. Show some respect.

[Not_An_Abba_Fan]

For performance bigger is not better.

You talk of restriction, a bigger exhaust can actually produce more back pressure than a smaller one. What you really need is exhaust velocity. It's not about how much exhaust gas you can move, but rather how fast you can move it.

If you want noise, by all means dump it at the diff, but if it is performance you are after then fit a 2 1/4" tail pipe to the 2 1/2" front section and you will be surprised at how much torque you regain.

A decent set of extractors, the standard cat and a proper exhaust will give you more response, better acceleration but very little "power". To gain more power the engine needs to be modified.

[Troy5L]

You can only dump near the diff if its 40cm behind the last perminently welded or sealed join in the floorpan. Basically that means, you can only do it if you have a ute.

i thought it was u can stop the exhaust with no less than 330mm from the end of the rear door

[Jesterarts]

^^^ That is like a secondary rule to the one mentioned by Andrew for instances in which your planning on having the exhaust exit out the side.... I think... although its illegal in australian to have exhausts come out the side... I'm really not too sure on this one... hmmm

Think of it this way... you have grommets in the boot... if the exhaust fumes get in the boot... they will get in the cabin...