What's The Legal Limit On Muffler Size?

[fcruz3r]

I have a 3 inch turbo back exhaust with a cannon tip muffler...dont have the cash to replace the whole system...not that theres anything wrong with it....but recently i bought an apexi dunk megaphone muffler which i intend to use....however it comes with a 4 inch inlet and 115mm tip....is that going to get me a yellow sticker?

[hanyou]

i thought as long as it hangs a certain height of the ground its ok.. and as long as it passes emmission/db reading.

[fcruz3r]

i thought as long as it hangs a certain height of the ground its ok.. and as long as it passes emmission/db reading.

height from ground ...i can get the exhaust shop to weld bracket hooks so it sits well and snug maybe even partially hidden..

as for db...im hoping it sound quieter than the cannon...which at present is as loud as #%^&

btw...anyone know of a good exhaust shop in perth NOR ...?

custom exhaust specialist in osborne park wont fit 2nd hand mufflers

[Ska]

Yeah height and sound level would be your only issues.

[STAGE-A]

height from ground ...i can get the exhaust shop to weld bracket hooks so it sits well and snug maybe even partially hidden..

as for db...im hoping it sound quieter than the cannon...which at present is as loud as #%^&

btw...anyone know of a good exhaust shop in perth NOR ...?

custom exhaust specialist in osborne park wont fit 2nd hand mufflers

if ya any where near mindarie ...mindarie custom exhausts are good and well priced

[fergo308]

as Ska has said,your only legal concerns are ground clearance,and Dba output.

design is irrelevant as far as legality is concerned.

my car runs twin 2" cannon and dual pipes from the cat back. it's pretty quiet,and has awesome ground clearance,with good flow,although it's a bit smaller than the usual 3" alternative.

Justin...

Edited October 26, 2006 by fergo308

[AlexCim]

Actually, the flow of twin 2 inchs pipes is not as good as a single 3 inch.

2 inchs = 12.5 sq inches

2 x 12.5 = 25 sq inches

2 inches = 28.3 sq inches

Twin 2.25inchs+ however have more flow.

2.25 inches = 15.9 sq inches

2 x 15.9 = 31.8 sq inches

[fcruz3r]

if ya any where near mindarie ...mindarie custom exhausts are good and well priced

I work in Scarborough so looking for somewhere nearby where i can drop the car off to have the muffler fitted and pick it up on the way home.

Ian Diffens at Osb Park quoted $200 for the job...not sure about the quality of works though...dont really mind the split donut pipe works ..just worried about them using the bender and crushing the pipes coz i dont think they do mandrel

[fergo308]

post edited accordingly Alex. thanks for the math.

justin...

[Ska]

Actually, the flow of twin 2 inchs pipes is not as good as a single 3 inch.

2 inchs = 12.5 sq inches

2 x 12.5 = 25 sq inches

2 inches = 28.3 sq inches

Twin 2.25inchs+ however have more flow.

2.25 inches = 15.9 sq inches

2 x 15.9 = 31.8 sq inches

I think that maths is flawed, one too many 2's in there

[3intheBack]

Correct me if I'm wrong, but the db limits you are looking for are:

Pre 1986 - 96db

Post 1986 - 92db

...but then some of you werent even born pre 86 so you wouldnt recognise 96db coming out of a straight thru 2inch system on the mini or a set of twin hotdogs bolted to a set of yella terra extractors on Torana XU1.

[AlexCim]

Ska - meh, 2=3

Id probably prefer twin 2's though, the % is only about 10% but ground clearance would be greatly improved, at least by 1/2 an inch (1.252cm)

[STAGE-A]

I work in Scarborough so looking for somewhere nearby where i can drop the car off to have the muffler fitted and pick it up on the way home.

Ian Diffens at Osb Park quoted $200 for the job...not sure about the quality of works though...dont really mind the split donut pipe works ..just worried about them using the bender and crushing the pipes coz i dont think they do mandrel

u work in scarborough.... and itz almost summer, lucky bugger!!! hahhaa

sorry mate i couldnt recommend any places round there but id say pretty much any shop should be able to do the work easily ...but yeah id definatley go to a shop that could mandrel bend.

be good to see it on the cruise

Edited October 26, 2006 by STAGE-A

[fcruz3r]

u work in scarborough.... and itz almost summer, lucky bugger!!! hahhaa

sorry mate i couldnt recommend any places round there but id say pretty much any shop should be able to do the work easily ...but yeah id definatley go to a shop that could mandrel bend.

be good to see it on the cruise

Mate,

My office is right above plaka's ....so if u notice a couple of idiots standing in front of the window with binoculars....give us a wave will ya...hahahah

If i can't get a mandrel bend...i'd prolly settle for the split donut approach.

[66yostagea]

I think that maths is flawed, one too many 2's in there

To much maths.

Try this,

Square the diameter, ie 2X2= 4

Two pipes, = 2X4= 8

Single 3" 3x3 =9

9 is more than 8.

[3intheBack]

Whatever happened to multiplying R X Pi (3.14159265)

...or does that just give you the circumference?

[AlexCim]

2 pi R = circumference

pi R squared = area

[3intheBack]

On a twin 2 inch system

R = 1 inch X pi (3.14) then square it = 9.88 cubic inches

times 2 pipes = 19.77 cubic inches

On a single 3 inch

R = 1.5 inches X pi = 4.7 squared = 22.22 cubic inches

So a single 3 inch pipe has more volumn then a twin 2 inch.

I rest my case...

[fergo308]

so it's been proven twice now that I f**ked up. anyone else want to do the math to rub it in a bit more?

Justin...

Edited October 29, 2006 by fergo308

[mike40sydney]

so it's been proven twice now that I f**ked up. anyone else want to do the math to rub it in a bit more?

Justin...

IM VERRY WELL EDUKATED I WENT TO THE 6TH GRADE 5 TIMES SO IM REALY SMART LMAO i dont wanna show em up lol