NCT Vehicle Exhaust noise

drunkmonkey

How loud is 99db? I've a straight through exhaust on my wrx, It's sounds sweet but maybe a little loud when you floor it.
What are my options to get it through the NCT, is the 99db measured when the car is ticking over or is it measured under revs?
Do I need a whole new exhaust?

Atomic Pineapple

It's measured under revs, around 3k I think.

99db is pretty loud and a fair compromise

However a wrx with a straight through is likely to be over it.

You could look into a bung for the exhaust to try to silence it a bit?

B00MSTICK

I'd pay the €50 and see what happens. I can see the NCT testers using some discretion if the car is a proper performance one.

drunkmonkey

I called the NCT and they said there's a book outlining the manufacturers specifications for the exhaust noise, should be interesting to see the Jap Wrx specifications.

How about these bungs, where do they fit in, it would want to be the size if a small child if it's to fit in the back box..

copeyhagen

its a silencer that fits into the outlet at the exit for your exhaust

Atomic Pineapple

The WRX standard would be fine, its the straight through that I'd be worried about

You'd need to but the cat back in to pass emissions anyway and that'll quieten it down a bit

tossy

draffodx wrote: »

The WRX standard would be fine, its the straight through that I'd be worried about

You'd need to but the cat back in to pass emissions anyway and that'll quieten it down a bit

Exactly its measure at 3k rpm from a distance of 1 metre and at a slight angle i think.

Atomic Pineapple

http://www.ncts.ie/pdf/nctmanual.pdf

page 84

drunkmonkey

it's only 64 pages:) thanks i'll have a read later...

who would have one of these db meters, not many garages I presume, any other trade that uses them?

Atomic Pineapple

drunkmonkey wrote: »

it's only 64 pages:) thanks i'll have a read later...

who would have one of these db meters, not many garages I presume, any other trade that uses them?

In the PDF Toolbar it shows 94 pages, just type in 84 there and it'll take you to the correct page.

I think I remember someone in main motors saying they knew garages(s) with them, perhaps search for that thread in main motors?

drunkmonkey

draffodx wrote: »

In the PDF Toolbar it shows 94 pages, just type in 84 there and it'll take you to the correct page.

I think I remember someone in main motors saying they knew garages(s) with them, perhaps search for that thread in main motors?

Cool thanks, Just bought myself a db meter, 79 cent on the app store, it's the one they used on top gear.
http://www.gadgetfrontier.com/apps/decibel

JimmyCrackCorn

drunkmonkey wrote: »

Cool thanks, Just bought myself a db meter, 79 cent on the app store, it's the one they used on top gear.
http://www.gadgetfrontier.com/apps/decibel

Best of luck getting an accurate reading with an un-calabrated device.

dcGT

drunkmonkey wrote: »

Cool thanks, Just bought myself a db meter, 79 cent on the app store, it's the one they used on top gear.
http://www.gadgetfrontier.com/apps/decibel

I'm curious now, did you get through the NCT? What was the reading on the app and how did it compare with the NCT result?

Cheers,

DC

The-Game

dcGT wrote: »

I'm curious now, did you get through the NCT? What was the reading on the app and how did it compare with the NCT result?

Cheers,

DC

+1 on that!!

Graham_B18C

I put my car through last week (ITR) and they never even measured the noise of mine. Well I didn't see them doing it anyway. Mine is pretty loud but I put a bung in.

Atomic Pineapple

Its only tested if the tester deems it may be too loud, not part of the test otherwise (same with tints)

Graham_B18C

draffodx wrote: »

Its only tested if the tester deems it may be too loud, not part of the test otherwise (same with tints)

Ah ha! I was wondering why my tints wern't tested either!

dcGT

Grahamo999 wrote: »

Mine is pretty loud but I put a bung in.

Where do you get one of these and what is it? Are the only available for certain exhaust types or cars?

Cheers,

DC

Graham_B18C

dcGT wrote: »

Where do you get one of these and what is it? Are the only available for certain exhaust types or cars?

Cheers,

DC

It's literally a circular plate with a pipe going through it, it restricts the amount of exhaust gas at the back of the exhaust pipe. If you have a modified or uprated exhaust it'll most likely have a hole in the bottom, that's for a bolt to hold a bung in.

If it has a hole, bring it to any performance car place (I generally use Urban Performance in Tallaght) and they'll show ya what you need. Mine came on the car but I can't imagine it'd be expensive to buy one.

Here's what they look like

http://cgi.ebay.ie/TUNABLE-EXHAUST-BUNG-INSERT-4-4-5-5-TAILPIPES-/350368017418?cmd=ViewItem&pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item51938fac0a

dcGT

Graham_B18C wrote: »

It's literally a circular plate with a pipe going through it, it restricts the amount of exhaust gas at the back of the exhaust pipe. If you have a modified or uprated exhaust it'll most likely have a hole in the bottom, that's for a bolt to hold a bung in.

If it has a hole, bring it to any performance car place (I generally use Urban Performance in Tallaght) and they'll show ya what you need. Mine came on the car but I can't imagine it'd be expensive to buy one.

Here's what they look like

http://cgi.ebay.ie/TUNABLE-EXHAUST-BUNG-INSERT-4-4-5-5-TAILPIPES-/350368017418?cmd=ViewItem&pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item51938fac0a

Thanks for that. I don't he has one of those holes in the exhaust, so a bung is not an option I guess. New back box it will have to be, if he can find one.

Cheers,

DC

Graham_B18C

dcGT wrote: »

Thanks for that. I don't he has one of those holes in the exhaust, so a bung is not an option I guess. New back box it will have to be, if he can find one.

Cheers,

DC

It's only a 6mm hole, drill it. Or bring it to one ofthe mentioned tuning places and they'll install it for you

dcGT

Cheers for that, but I think the tailpipe on the exhaust is a thick-ish one (10mm or so), not the required 1 mm pipe. It's a bit like the attached.

I don't think it'll work then?

Cheers,

DC

gordonjj

Graham_B18C wrote: »

I put my car through last week (ITR) and they never even measured the noise of mine. Well I didn't see them doing it anyway. Mine is pretty loud but I put a bung in.

Which exhaust are you using?

Graham_B18C

gordonjj wrote: »

Which exhaust are you using?

Cat back stainless tanebe, think it's a 4". It's coming off in the next two weeks. Going to put the standard one back on. My insurance comp want over 400 quid extra this year if I leave it on!!!

bla1988

why dont you just buy a apexi ecv can make it loud and quite from the comfort of your own car by the twist of a knob or somthing like that

gbee

drunkmonkey wrote: »

How loud is 99db? ?

It is very loud in fact. Top Gear got just 65db out of a few super cars under the Kremlin or something like that, a massive underground car park/nuke bunker and they floored their machines ... I had predicted 150db ~ but what do I know?

LOUD was just 65db so even some very loud cars are still going to get through.

Graham_B18C

gbee wrote: »

It is very loud in fact. Top Gear got just 65db out of a few super cars under the Kremlin or something like that, a massive underground car park/nuke bunker and they floored their machines ... I had predicted 150db ~ but what do I know?

LOUD was just 65db so even some very loud cars are still going to get through.

99db from 1 metre is loud but mine would of failed without the bung. 65 db in a tunnel is different than pointing it straight at the exhaust