Noise-metering examples on the Internet?

[peter_964rs]

Can someone point me to examples of cars that have passed / not passed noise metering exams at Bedford Autodrome. I am trying to persuade a friend with last-model M5 (V8 engine) and Kelleners aftermarket exhaust to come to a track day on the 26th at Bedford and the noise limits are 101db static and 87db drive-by at 20m. Short of going somewhere to get it tested, some examples of similar cars and setups would be useful!

thanks

[fergus]

bookatrack (or easytrack) hire out a noise meter for circa £20 (posted, etc). I think it may be well contacting them to see how the (static) test is conducted and hiring the noise meter off them for a day or so. It is also worth remembering that the tests are done when the engine is not under load. The true 'drive-by' test may be a higher reading.... good luck!

[combemarshal]

the test should be done at 45 degrees half a metre for the exhaust at 4500rpm.
If it is twin exit (ie one each side of the car) then there is a good chance it will go through, If it doesn't go through a 101 test i'd be surprised, You'd be death after every journey!
What do MX5's rev to, aren't they slightly higher than the average car, like a Honda??

[peter_964rs]

That's M5 not MX5. German not Japanese, four door not two door, etc!

Big engine with big exhausts equals slight concern over eligibility. I'll suggest the Bookatrack route and/or attendence at another track day just to be metered!

[combemarshal]

Dam it!!!

BMW's aren't that loud anyway!
You could try here
www.maplin.co.uk/Search.aspx?criteria=sound%20meter&doy=3m8&source=15
Use then bring it back!

[peter_964rs]

What a good idea! But is he brazen enough to carry it off.....?

[raceface]

He could look for a track day close to where he is & go & get tested there?

My 205 with either blocked or missing baffles registered 100db at a 45 degree, 1 metre static test at 3/4 of rev limit (standard testing criteria). It is loud & definitely tiring on a journey.

[combemarshal]

Standard is half a metre, plus continuos track side monitoring throughout the day

[raceface]

Half metre; my apologies.

[chubbsr1]

I just did Elvington in my car this weekend and I couldn't get on in the morning because my car was at 107-108db...

Managed to get a baffle for it at lunchtime and that brought it down to 104.7db, with a 105 limit..

Make sure when you are going on the trackdays you get your car tested, or you'll end up wasting half a day like me..

[mko9]

I have a Skyline GT-R with a single pipe decat exhaust. I couldn't get the cat reinstalled in time for a trackday at Bedford and was worried about the noise level. I passed with a 97dB on the static test. Never had an issue with the drive-by, either. Don't know how useful that is for comparison, but at least it is a data point.

[lemon yella rs]

"standard" whoose? my experience is that some tracks test in different ways, with the noise meter being used in all sorts of positions! The only standard i know of is the MSA book, which is for race cars not track days afaik??