Noise Testing (for track days)

[mika]

Ive been to several track days during 2011 and plan to do a few more this year
However whilst my car is a standard 457bhp C63 the db readings appear to be increasing..

a few points
last time out i had to repeat the static test it was just under 98db which was the limit for that day and i received one warning during the drive by readings (limit 96db)
previous sessions have been 105db days so it was no issue and i believe my readings were 94db in static mode in any case

are my silencers becoming less effective ? - ive done 28,000miles
are these tests a little bit approxiamate or even a black art !the tester did comment that weather could affect the reading etc etc
i am not aware of any other C63s struggling with the db limits , some of which are 487bhp or even 500+ bhp

some of the exotica were "lifting" at various parts of the circuit (Goodwood)to keep from infringing
surely im not going to have to do that in mine

Even found some db reducing tubes but doubt they will fit and they seem a bit makeshift

 

[Simon_M]

Might need to keep an eye on them to check they are doing it at the 50cm distance.

Maybe it's just your club foot!

 

[wemorgan]

I gather the wind direction plays a part.

 

[10EDD]

I've read they tend to get louder with use. No idea if this is clouding my judgement but I'm sure mine is louder than when new, anyone else found this?
Edd

 

[mika]

Might need to keep an eye on them to check they are doing it at the 50cm distance.

Maybe it's just your club foot!

do your ladders deflect the sound away?

 

[gaz_l]

Even found some db reducing tubes but doubt they will fit and they seem a bit makeshift

A suitably sized potato hammered into one of the tailpipes should produce the noise reduction you're looking for...

Cheers,

Gaz

 

[mika]

there you go ...
Im a non techy who tries his hand at what i thought was an interesting and unusual topic
and all i get is

potatoes, wind and clubfeet !!



Hi Gaz - are you going to join us on a track day or two during 2012?

 

[wemorgan]

Plan B - lie about the red line rpm. The static test is done at a % of that so a 500rpm reduction might be all it takes to get you back under the limit. Though you'll still need to back-off when going past the track side sensors.

 

[Alps]

hey Mika, as the cars wears in the exhaust will get louder, also it will be louder if you have just done a long drive.

 

[mika]

so shall i drive down the night before in future
and maybe ask mercedes for a new exhaust system under warranty..

 

[gaz_l]

Hi Gaz - are you going to join us on a track day or two during 2012?

I'm doing the Vmax event but due to some uncertainty at work I'm being non-committal regarding other stuff. A shame, as the Goodwood day in August was the most fun I've had in a long time, but these days you have to be prepared to trim sails if necessary..

Cheers,

Gaz