Exhausts and DB noise levels

[Evogone]

Mines 96db @ 4k just got a rear silencer on the Cup racer.

Never been a problem.

Your issue will be induction noise, only solution is airbox on the ITB's.

[Robertio]

Ive had another centre section silencer added today, has lowered it a bit but when you open the engine up it roars!!!

Will have to wait till i can get it properly checked out at a track day or someone with a noise meter.

If you only need it for a couple of days I have one I could post down to you - just cover postage and I can send it down.

I'm having similar problems as I just finished my track car and it is showing 108db at 4.5k rpm through a straight 3.5" exhaust. Some silencing is pending once the new clutch turns up and I can actually drive it. It took me a while, but I got my old 500bhp RX-7 down to
Idle: 83db
4.5k rpm: 90db
6k rpm: 93db
Through a 3" system (being turbo'd helped a bit). So it should be possible to get the volume down, just a matter of the right level of silencing in the right place, problem is it tends to add a fair amount of weight.

[Coops]

how and where did you get it checked? can it be done as a check before say i drive all the way to germany only to find its too loud? :P

[Coops]

how and where did you get it checked? can it be done as a check before say i drive all the way to germany only to find its too loud? :P

[teabag]

how and where did you get it checked? can it be done as a check before say i drive all the way to germany only to find its too loud? :P

couldnt an mot centre do it?

[stevie_b]

Not unless the MOT centre has a dB meter, and I can't think that many would. I've got one I could bring along to RWS, if you are going to that in a couple of weeks? Failing borrowing one just rock up to any race/sprint/hillclimb meeting and there will always be a scrutineer there with one that will probably happily measure your car if you tell them you are thinking of competing it in a future event.

If you think you may be over the limit at an event you can buy a 'bung' that you just stick over the end of the exhaust to lower it. I use that on my cars as they are fine at circuits with 105dB limits but I kept getting thrown off Goodwood which has a strict 98dB limit so need to quieten it down pretty much just for there and then can take it off again.

[richy]

coops ring easytrack up, they will do a static test if you pop along to a trackday, dont have to be booked on for that tackday aslong as you ring before hand

[evouk]

Ok thanks for offer of sound metre, will be in touch when i have finished a few things.

I wont be able to check drive by noises but static test should be ok.

At oulton last week they asked for 4800 rpm, i couldnt get it to stick at 4800 so think he measured it at 5400 rpm and it made 100 DB so sure it may get 98db at 4800.


The only next idea is to change the exhaust to a 2.5 inch system with a big east to west silencer at the rear.

[Allan]

http://cgi.ebay.co.uk/Professional-7...QQcmdZViewItem

much cheapness :D