trackday noise testing procedure

White Noise · Mr Dudwee Joined: 17 Dec 2004 Karma :

going a trackday at the end of the month and i think that limit is 105 dB, fair enough. just want to check that the level of my can is below that, i've got Type 1 sound level meters at work so i can use them but i want to know the actual test procedure they are working against, i've been told that its with the mic 0.5 metres back at a 45 degree angle to the rear of the bike, with the bike at 3/4 max revs. also guessing that measurements are to be made in free-field conditions with the only significant reflection surface being the ground
anyone able to tell me if that is correct or not?
Cheers
WN
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Silver · World Chat Champion Joined: 03 Oct 2004 Karma :

Decibels are supposed to be measured at a distance of one metre (I believe) although places like Castle Coombe do it from about three millimetres!

Don't worry, your bike will be fine. Most places don't test as such, they just monitor the noise throughout the day. At Oulton Park we were tested individually and RealNinja passed - he's got a ZX7R with an Akrapovich illegal full system. So unless you have anything noisier than that ( Shocked

), you'll be fine.

105db is okay, it's when you get the 98db days you have to worry. 105db is actually very loud (it's an expenetial curve, not a linear one, so you need something like ten times the decibel rating to appear twice as loud).

White Noise · Mr Dudwee Joined: 17 Dec 2004 Karma :

Silver · World Chat Champion Joined: 03 Oct 2004 Karma :

stinkwheel · Bovine Proctologist Joined: 12 Jul 2004 Karma :

Bolt an empty coke tin inside the end can for the noise test. Keep off full throttle until you have passed then blast the sucker out.

Or so I have been told.
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White Noise · Mr Dudwee Joined: 17 Dec 2004 Karma :

Silver · World Chat Champion Joined: 03 Oct 2004 Karma :

White Noise · Mr Dudwee Joined: 17 Dec 2004 Karma :

RealNinja · World Chat Champion Joined: 18 Mar 2004 Karma :

Gilderoy · Nova Slayer Joined: 22 Sep 2005 Karma :

At Croft yesterday and a K5 GSXR 1000 with a full race system put out 109db and got told to change it or go home as he wasn't going on the track.

Look out for stubby cans like the new K5's, not enough in there to keep them quiet.