Trackday dB limits

[tannertime]

Am due to take the cerb on a trackday in a few weeks time and they're stipulating a 'strict' max 100dB(A) limit.

Does anyone know what levels Cerbs usually register?

(mine's a S6 so assume she'd be slightly quieter than you noisy V8 lot?!?).

Cheers, JT

[VYT]

Only ever seen one Cerb make 100dB without additional silencing at Castle Combe.

My 4.2 Decat but standard silencer was 118.

Typical seems to be about 106, (4500rpm 0.5m).

My T350 (S6), was 97.3 this year.

[dai capp]

Not many V8 cerbs make 100Db.

Mines 119Db at 4K RPM at an offset which would be even louder at the centre point between the pipes (so I'm told). However it is decatted with a sports exhaust so a little louder than the norm.

I had 2 Tuscans before this though one put out 105Db and the other 98Db so a speed six with a standard exhaust may well make the mark.

There are various tricks that can be used to reduce the noise levels and I think ACT sell trackday silencers which should help.

You can also get Db meters from places like Maplins so you could find out for yourself. It'd certainly be cheaper than forking out for a trackday and then finding you're over the noise limit

All the best

DC

[cruty]

I was recently at the TVRCC Castle Combe event and passed the noise test in my 4.2 at 94.5Db!!

The car has been decatted, but has had straight through Jetex silencers put in their place. The rear box is the standard part, but i had recently cut it open and re-packed it, as their was hardly any wadding left. This made a big difference to the noise - very quiet, with no pops or crackles on the over run (hence why i have a sports exhaust for everyday use ). But as a cheap altenative to add on silencers is well worth doing.

ps you can get the wadding from any local exhaust manufacturer or people like Merlin Motorsport for about £15 per Sq meter

[simonsparrow]

Interesting, where did you get the Jetex silencers from, did they bolt straight on?

My Cerbera currently has an 'Asymetrical cat' system in place (i.e. I've burnt out one cat due to a failed O2 sensor, so it's now hollow ).

Prior to this, it registered 112Db at Bedford (cats plus sports exhaust) during the static test. However, it never triggered off any of the trackside meters (set at 87.5Db if I recall), so I was OK going round.

[cruty]

I purchased the two jetex silencers from Merlin motorsport. I think the silencers were 2 1/2 inch straight through and about 420mm in length. They cost about £45 each. I did have to do a small mod to the silencers in that they had to have the proper end attachments welded/fitted in place, so that they would fit to the manifold and middle section of the exhaust.
I did previously have straight through pipes fitted, with a Penisula sports exhaust, but found this to be a little too loud. But with the Jetex silencers in place its not as harsh and sounds a lot better and probably helps in terms of track day limits (when fitted with a standard rear box).