Andy North
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| posted on 18/10/05 at 06:50 AM |
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Noise
Although I don't consider the car to be too noisy, I am concerned that if I turn up at a track day in the UK, it will be above 105dB(A). Worth
noting here that it had two silencers for the SVA!
The question is two fold:
1) How can I get the noise down for a track day?
2) Has anyone tried the after market bike cans?
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nick205
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| posted on 18/10/05 at 07:28 AM |
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Andy,
I think you can buy sound level meters pretty cheap (£15-20) from the likes of Maplin or RS. Might be worth checking the noise level you currently
have before spending out to reduce it.
HTH
Nick
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Andy North
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| posted on 18/10/05 at 08:14 AM |
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Good point Nick.
At what distance away and revs do you measure at?
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ChrisGamlin
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| posted on 18/10/05 at 08:19 AM |
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After market bike cans are generally very noisy, don't be fooled by their noise level ratings because road bike regulations are measured
differently to how you'd be measured at a circuit, so a can that claims to be say 90db will be something like 105-110db as measured at a circuit
(0.5m, 45 degrees from exhaust exit).
Really the only thing you can do is get a large custom made silencer to go on it, something like 7" x 30" for a busa seems to be the
minimum if you want to be sure. Also look at the induction side of things, run the bike airbox if you can get it to fit, or if not consider making /
buying a custom made box. The reason for this is that a lot of the driveby noise you'll get is from the induction side of the engine when its
under load, so circuits that monitor the noise out on circuit like Donington and Goodwood will still catch you even if you can pass a static test.
Chris
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Andy North
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| posted on 18/10/05 at 10:01 AM |
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quote:
Originally posted by ChrisGamlin
After market bike cans are generally very noisy, don't be fooled by their noise level ratings because road bike regulations are measured
differently to how you'd be measured at a circuit, so a can that claims to be say 90db will be something like 105-110db as measured at a circuit
(0.5m, 45 degrees from exhaust exit).
Really the only thing you can do is get a large custom made silencer to go on it, something like 7" x 30" for a busa seems to be the
minimum if you want to be sure. Also look at the induction side of things, run the bike airbox if you can get it to fit, or if not consider making /
buying a custom made box. The reason for this is that a lot of the driveby noise you'll get is from the induction side of the engine when its
under load, so circuits that monitor the noise out on circuit like Donington and Goodwood will still catch you even if you can pass a static test.
Chris
Chris,
The standard air box was modified and is on (still made me deaf in the left ear during track day)
Do they use a particular rev range for the noise test?
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Hellfire
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| posted on 18/10/05 at 11:27 AM |
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Static is usually tested at three quarters of maximum RPM. Drive-by......... well, thats wherever the meter is positioned on the track. If it's
on a particularly long fast straight like at Donington, chances are you're gonna be doing around 10,000 RPM as you go by.
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ChrisGamlin
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| posted on 18/10/05 at 11:48 AM |
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Yep sorry, as Hellfire said, usually 3/4 max rpm or 3/4 max power rpm (which is when you try to convince them that your BEC produces peak power at
about 7k  )
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