Help! - Clubsport noise levels
Discussion
I need some help figuring out how to make 87db on a drive by with an old clubsport 1100. I have a SR4 exhaust fitted and told that it will pass 98 db without problems (been to Donington Park twice without complaints).
I am in Switzerland and doing my equivalent of the ARDS test at Hockenhiem (no race tracks in Switzerland). The test is two days of on-track observation with an instructor.
I have heard that stuffing the exhaust with steel wool with quiet it down, but how much and for how long? How many revs can I drop to try and achieve this limit. Since it’s not a race or track day I don’t really need to push too hard.
I know that there are a few tracks in the UK with strict noise limits and maybe some of you have some experience in making tough limits.
Cheers - Jon
I am in Switzerland and doing my equivalent of the ARDS test at Hockenhiem (no race tracks in Switzerland). The test is two days of on-track observation with an instructor.
I have heard that stuffing the exhaust with steel wool with quiet it down, but how much and for how long? How many revs can I drop to try and achieve this limit. Since it’s not a race or track day I don’t really need to push too hard.
I know that there are a few tracks in the UK with strict noise limits and maybe some of you have some experience in making tough limits.
Cheers - Jon
it's impossible to make tough limits IME. Mind you, do you have any more info on the limit? How far away is the noise meter? Looking at the Donny regs they have a 98dba drive-by limit which is marginal for a clubsport (well any radical).
If you can use half revs for example you may get away with it. I have tried a new SR4 quiet box plus a dongle on the back and it doesn't get it very quiet.
If the "it'll pass 98db no probs" had "guv" on the end and came from a radical factory source then it's somewhere between wishful thinking and complete bollox. The SR4 quiet box is billed as the 98db box that can pass a 98db static test. At a combe track day, the quietest I could get with 3 yellows which is what was asked for and with another dongle on the back was 102-103. Upon questioning (I was a bit dischuffed to say the least) the factory admitted that you needed to do the static test with 1 yellow just flickering and you might just make it. I'm ranting now, I'll get me coat!!
Good luck with the test. An extra dongle on the back might help, gets rid of about 2dba.
GRaham
If you can use half revs for example you may get away with it. I have tried a new SR4 quiet box plus a dongle on the back and it doesn't get it very quiet.
If the "it'll pass 98db no probs" had "guv" on the end and came from a radical factory source then it's somewhere between wishful thinking and complete bollox. The SR4 quiet box is billed as the 98db box that can pass a 98db static test. At a combe track day, the quietest I could get with 3 yellows which is what was asked for and with another dongle on the back was 102-103. Upon questioning (I was a bit dischuffed to say the least) the factory admitted that you needed to do the static test with 1 yellow just flickering and you might just make it. I'm ranting now, I'll get me coat!!
Good luck with the test. An extra dongle on the back might help, gets rid of about 2dba.
GRaham
RobC said:
The drive by at Combe is 89dB at race meetings iirc and I've never had a problem so long as the exhaust has been freshly packed. Static is around 103-106dB depending on weather conditions
Nearly.
105dB(a) - drive by threshold is 93 dB(a) +/-0.5
108dB(a) - drive by threshold is 96 dB(a) +/-0.5
Above this and you get a post session check at 0.5m
Have you fixed your engine/gearbox yet?
On the original subject - how far is the mic from the trackside?
Can you increase the distance much by being on the opposite side of the track?
Edited by PaulV on Wednesday 6th September 18:02
Yes I've got the gear box fixed. Unfortunately, I needed a rebuild. Since then I managed to get in 2 days at Spa and a day a Dijon. Hopefully I can manage another day or two before the end of the year.
As for where the mic is/are at Hockenhiem, they don't want to say. I'm guessing around 3 or 4 meters maybe somewhere on the pit strait (like donington) and I would also think somewhere else around the track.
As for where the mic is/are at Hockenhiem, they don't want to say. I'm guessing around 3 or 4 meters maybe somewhere on the pit strait (like donington) and I would also think somewhere else around the track.
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