are 2.5 and 3 inch exhaust over?

[Heffer_Slayer]

Hey everyone i am just wondering if i keep my stock extractors and put on a new exhaust system from the cat, would i be over the legal dB limit?

Im in Vic and not sure what the limit is, i just wouldn't want to go over.

I am thinking a 2.5 inch of 3.0 inch system for my VT, what are your opinions?

Thanks!

[Noy]

I "THINK" 100 DB is the limit, but im not 100% sure on this.

Though put a 2.5" exhaust, my mate has a stock VT with 3" exhaust and he has lost power and wishes he got the 2.5".

[Heffer_Slayer]

Hmmm does anybody know if a 3.0 or 2.5 inch exhaust system goes over that? With stock extractors and without,

Cheers

[Not_An_Abba_Fan]

The ADR requirements are the same no matter which state you are in. From memory the VT would need to meet post 1986 levels which are 90dBA. Almost every aftermarket exhaust will fail the test and if the meter used isn't in the correct position then stock exhausts will fail also. The trick is to get what you want fitted and not to drive it as to attract any unwanted attention. I would go for a 2 1/2" system that is mandrel bent with a free flowing front muffler. Some people like to have straight through pipe on the front and only have a free flow muffler on the rear. Personal choice, try to listen to a few exhausts and quiz the owners on what they have. Do not go for 3" as you will lose too much back pressure and sacrifice low down power. Good for top end but not much else. I assume you have a V6.

[Heffer_Slayer]

Yea i have a 6, just got her
Hmmm are you serious even stock exhausts will fail! Wow...my car is quiet as a mouse so i dont no how that would work!
Are you 100% sure that it would fail the dB test with a 2.5 inch straight threw?

[Noy]

Yeah it would fail, but its rare to get pulled up for an exhaust. Im sure 99% of the people on here would fail the db test.

[Not_An_Abba_Fan]

Originally Posted by Noy

Yeah it would fail, but its rare to get pulled up for an exhaust. Im sure 99% of the people on here would fail the db test.

Exactly, but it depends on how you drive it when the authorities are within earshot.

Hmmm are you serious even stock exhausts will fail! Wow...my car is quiet as a mouse so i dont no how that would work!
Are you 100% sure that it would fail the dB test with a 2.5 inch straight threw?

The test procedure is only as accurate as the person testing. You need to be in an open space where no ambient sound is present, also nothing that the noise can be reflected back off. The noise level meter needs to be 1 metre from the exhaust outlet, at the same height and at a 45 deg angle. The engine needs to be revved to 75% of its limit, if this isn't known then about 3000 - 3500 rpm will do. Usually most cars will fail due to the conditions not being met not because it is too noisy. Then there is the drive by test......

[walesy]

3" on a 6 is an overkill... unless its turbo or s/c there is no need for such a big pipe and as said you will only lose power and it will sound like crap... 2.5" is popular because its just about the right size

[TigerVX]

The output of the exhaust will vary depending on brand and how it is set up.

[Heffer_Slayer]

Well say a 2.5 catback or lukey system? And say a dual tip on the end? Would they be under the dB Limit?

When getting a car road worthy do they check the dB? Because someone said that even some stock exhausts are to loud.

Thanks for all the input so far

[younggun]

i bloody hope a 2 1/2 inch passes a rwc cause i gotta get me stato regestered and im getting a 2 1/2

[Heffer_Slayer]

Originally Posted by younggun

i bloody hope a 2 1/2 inch passes a rwc cause i gotta get me stato regestered and im getting a 2 1/2

when abouts are u doing to get it done can you post up how you go when u get your rwc?

[mattman]

Legality would depend alot on the mufflers too, i mean really you know how loud your own car is

2.5" is definitely the way to go, I had a 3" (twin 2 1/4 to rear mufflers, joined to 3") tail end on my supercharged calais and even on that it was too big.