Tris
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| posted on 29/6/11 at 04:02 PM |
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Noise Limits at track days - am i going to have a problem ?
Hi all,
Ive booked my spire into a couple of track days next month, one at Castle Coombe (which limit for a car, even with a bike engine, is 100db @ 4,500
rpm), and the Silverstone National Circuit (105db drive by is all thats stated).
I have just been out and using my ebay noise measurer, it measured 94db @ 1/2m @ 4,500 rpm, and 99.7 db at 8,000 rpm.
A 'drive by' was about 93db.
I know that its hard to say, but does anyone think i am going to have a problem at either of these circuits ?
Cheers
Tris
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eddie99
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| posted on 29/6/11 at 04:03 PM |
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Nahh you'll be fine, just say its max RPM is 10000 not 13000 
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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matt_gsxr
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| posted on 29/6/11 at 04:17 PM |
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93 dB is a lot less then 105dB (the scale is logarithmic).
If you are worried then pick up and trial fit an exhaust baffle in advance. They are only a few quid and will remove a worry.
Worth trial fitting it first (i.e. drill a mounting hole in your exhaust so it bolts up).
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locoR1
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| posted on 29/6/11 at 04:24 PM |
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After hearing your car at PPC in the park at Mallory i would be surprised if you have to many problems with noise, it sounded very quite
 
Description
Check out my CB500T Cafe Racer build diary
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Tris
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| posted on 29/6/11 at 04:29 PM |
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Ah, the day when the rear wing snapped in half 
Cool - there's a few different types of baffles on ebay - is there a good one to go for ?
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locoR1
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| posted on 29/6/11 at 04:49 PM |
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quote:
Originally posted by Tris
Ah, the day when the rear wing snapped in half
 Didnt know that 
Was also the day my mates MK blew its head gasket in spectacular style
Description
Check out my CB500T Cafe Racer build diary
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JonnyS
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| posted on 29/6/11 at 05:34 PM |
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quote:
Originally posted by Tris
Hi all,
Ive booked my spire into a couple of track days next month, one at Castle Coombe (which limit for a car, even with a bike engine, is 100db @ 4,500
rpm), and the Silverstone National Circuit (105db drive by is all thats stated).
I have just been out and using my ebay noise measurer, it measured 94db @ 1/2m @ 4,500 rpm, and 99.7 db at 8,000 rpm.
A 'drive by' was about 93db.
I know that its hard to say, but does anyone think i am going to have a problem at either of these circuits ?
Cheers
Tris
Based on that you'll fail Castle Combe. They are utter ba$5ards. They will measure you at 3/4rpm, so approx 9k ish? Whatever your noise meter
says, they'll be 3db higher as well  Believe me, I've been a few times, and gone home once without running.
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Dusty
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| posted on 29/6/11 at 06:04 PM |
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Castle Coombe are fighting for survival against a couple of villagers who rent there. Any excuse and they are off to court. I suspect the tracks days
are numbered unless the courts have some sort of common sense forced upon them. That's why they are so paranoid about noise limits.
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MK9R
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| posted on 29/6/11 at 06:06 PM |
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Yeah combe are real b@stards, I failed there on the static test, bought an over priced muffler from merlin, fitted it and they reckon I was 3db
higher!! I drove it round the paddock a few times, went back and was more careful how I applied the peddle and passed 8db lower than before!!!!
Makesure you get it hot, makesure you lie about the rpm limit (and be warned the bloke I had knew bike engines and spotted what I had), rev it upp
very slowly so you don't go over or blip it as it makes a louder spike and also take something to try and muffle the end. Once you are on
circuit you shouldn't have a problem
Cheers Austen
RGB car number 9
www.austengreenway.co.uk
www.automatedtechnologygroup.co.uk
www.trackace.co.uk
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gaz_gaz
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| posted on 29/6/11 at 06:22 PM |
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i was 97db at Brands Hatch with an Akrapovic exhaust, and 97db at Castle Combe.
Maybe see when your local track are next having a track day and pop over and have them do a noise test using there equipment?
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macc man
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| posted on 29/6/11 at 06:39 PM |
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Take some wire wool to stuff up the pipe. We find loads of it on the track after a blast round the circuit.
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gaz_gaz
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| posted on 29/6/11 at 07:32 PM |
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i done an evening session at Brands and a girl there in an mr2 turbo couldnt pass noise even with her bung in,
so she disappeared for 10 minutes and came back with a pack of Brilo pads, she stuffed them in the exhaust then fitted the bung and passed noise test
with ease,
removed them and didnt have any issues with the drive by.
rather ingenious i though!
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norfolkluego
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| posted on 29/6/11 at 11:37 PM |
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Wouldn't necessarily trust yourself/meter to get it right, before we started sprinting I was worried we'd fail the noise test so I bought
a meter and tested it. We passed scrutineering OK at 93dB, two days after I'd tested it at 117dB
Don't bother any more
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