Noise Limits on Track Days...
Discussion
Definitely not urban myth. The static test in the paddock is for individual cars. The drive-by's which the council monitor apparently allow them to take action if the "average" gets too high. I've been on a trackday there before now where we've stopped for an extended lunch at 11:30am just to get this "average" back down again.
I think I am going to have to retest the car, but I *think* I did everything correctly.
It was at 45 degrees from the exhaust, and with two tests (one at 1m and one at 0.5m). The engine has a redline of 6800 rpm, but the tacho has a moveable redline, so for the purposes of scrutineering that might get adjusted down to a visible 6000
So both my tests were at 4500 rpm.
The only thing I thought of afterwards was that I'd left the engine cover off, but that's only a very flimsy bit of fibreglass, so I can't see that it made a huge huge difference ... (or .... ?)
Will retest and report
It was at 45 degrees from the exhaust, and with two tests (one at 1m and one at 0.5m). The engine has a redline of 6800 rpm, but the tacho has a moveable redline, so for the purposes of scrutineering that might get adjusted down to a visible 6000
So both my tests were at 4500 rpm. The only thing I thought of afterwards was that I'd left the engine cover off, but that's only a very flimsy bit of fibreglass, so I can't see that it made a huge huge difference ... (or .... ?)
Will retest and report
Okay, so here's the exhaust retest info :
Last night, middle of a field in middle of nowhere.
Meter set at weighting 'A', held at 1m from exhaust tip, at 45 degrees, level with exhaust (i.e. about 8" from floor)
Run One : gradually increase revs gently to 4500 rpm : 108.5 db
Run Two : gradually increase revs gently to 4500 rpm : 107 db
Run Three : foot slips, accidentally rev hard from 3500 to 4500 rpm : 118.6 db !!!
So, unless the meter is incorrect, if I increase revs gently then it's "quiet" ish, but if I accelerate hard (as per going round a track, for example) then nearly 120 db is easily achievable !
Ulp !
Last night, middle of a field in middle of nowhere.
Meter set at weighting 'A', held at 1m from exhaust tip, at 45 degrees, level with exhaust (i.e. about 8" from floor)
Run One : gradually increase revs gently to 4500 rpm : 108.5 db
Run Two : gradually increase revs gently to 4500 rpm : 107 db
Run Three : foot slips, accidentally rev hard from 3500 to 4500 rpm : 118.6 db !!!
So, unless the meter is incorrect, if I increase revs gently then it's "quiet" ish, but if I accelerate hard (as per going round a track, for example) then nearly 120 db is easily achievable !
Ulp !
My car tested at 108db @5200rpm at Goodwood yesterday, some repacked silencers are in order.
Anyone know who could make some repackable ones that will lose this kind of noice and how much!
I don't really want to use some of those stick out the back things unless I have no choice.
Its an Ultima by the way.
Anyone know who could make some repackable ones that will lose this kind of noice and how much!
I don't really want to use some of those stick out the back things unless I have no choice.
Its an Ultima by the way.
BTB Exhausts got mine down to 101 (it's an R500)... website: >> www.racecar.co.uk/btb/
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It still sounds like you are testing it incorrectly. I'm trying to find a diagram of how to test it correctly for you
Okay ... quite happy to be corrected if so ... but from my descrption above, what could I be possibly doing to affect it radically ?
When cars are tested at SVA the probe is placed at 1m from the exhaust, level with the exhaust tip (same height from floor) and at a 45 degree angle. That's what I did.
getcarter - thanks for the URL ... how much did the box cost ?
It still sounds like you are testing it incorrectly. I'm trying to find a diagram of how to test it correctly for you
Okay ... quite happy to be corrected if so ... but from my descrption above, what could I be possibly doing to affect it radically ?
When cars are tested at SVA the probe is placed at 1m from the exhaust, level with the exhaust tip (same height from floor) and at a 45 degree angle. That's what I did.
getcarter - thanks for the URL ... how much did the box cost ?
All the tests that I've ever seen done have always had the meter at 45 degrees in all angles. So the tester is not level with the exhaust but 1m (or 0.5m) away 45 degrees from the exhaust outlet. Imagine if you taped a metre long stick to the end of the noise tester then touched it at the exhaust outlet and held it at 45 degrees from the horizontal and vertical (god this is so hard to describe.. and I can't find a picture anywhere !)
Andy
BookaTrack.com
Andy
BookaTrack.com
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