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Old Jan 14, 2010 | 07:52 AM
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Default track day/road exhaust noise testing?

hi peeps, does anyone know how a noise test is conducted for a track day or roadside test. Its just that i am looking forward to doing some trackdays this year so i just stood at the back of my car (idling) with a db(c) meter and it registered 113db(c), i know your meant to use a db(A) meter but i havent got one yet and if i did have one i would'nt know how to test the car properly would appreciate any help thnks rob.
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Old Jan 14, 2010 | 08:19 AM
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Hi mate i do lots of track days and i got pulled in last time at oulton park, not to sure what they use but they stick something up your exhaust and get you to hold the revs at around 5,000 for a few secs, best thing is get a bung made up and take it to the track with you , thats what i do just incase mate saves you getting thrown off .
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Old Jan 14, 2010 | 08:23 AM
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It depends on which track tbh.

Bedford and Donnington forget unless you are running std exhaust or on special noisey days.

Cadwell, Oulton, Brands, Silverstone, Snetterton etc are 105db at 2/3 max revs.
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Old Jan 14, 2010 | 08:49 AM
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Does anyone know what a standard PPP system measures?

Out of all the circuits i've driven in the Uk, for some reason i really enjoy Donington, just need to see if they re-open it now

I think it helps only being 45 mins away , great for the evening sessions.

Back to the op's question, they measure noice at 45 degrees to the exhaust at a distance of 0.5m and 2/3 or 3/4 max revs.
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Old Jan 14, 2010 | 10:06 AM
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My ppp exhaust is usually between 87 and 88 db on the static test. Never had a problem with noise at a track day!
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Old Jan 14, 2010 | 02:16 PM
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Originally Posted by robimportwagon
hi peeps, does anyone know how a noise test is conducted for a track day or roadside test. Its just that i am looking forward to doing some trackdays this year so i just stood at the back of my car (idling) with a db(c) meter and it registered 113db(c), i know your meant to use a db(A) meter but i havent got one yet and if i did have one i would'nt know how to test the car properly would appreciate any help thnks rob.

Hi Rob

They stand behind the car with the meter one metre away from the tailpipe at a 45 degree angle. The accomplice runs the car at around 4500 rpm, roughly two thirds max rpm, and then they say "yes" or "no"
If they say "no" it's no good arguing, you just have to slink off and do something about it. Castle Combe run at 100db , or did last year, there's talk of tougher than that. They can also get you on a drive by. I suffered that once, where my twin turbo Sierra passed the noise test, but they dragged me in as it went by and deafened them..
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Old Jan 14, 2010 | 02:58 PM
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Originally Posted by dynamix
It depends on which track tbh.

Bedford and Donnington forget unless you are running std exhaust or on special noisey days.

Cadwell, Oulton, Brands, Silverstone, Snetterton etc are 105db at 2/3 max revs.
Bedford Autodrome was 105 dba @ 75% of max revs. when I was there in 09

JohnD
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Old Jan 14, 2010 | 03:22 PM
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480 BHP.COM im in nottingham donnington is also my favorate track you must be local to me then.
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Old Jan 14, 2010 | 04:09 PM
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If you have an iphone you can get an apt for it (I dont know accurate it is) so you can do your own test. You need to hold it half a meter away at a 45 deg angle from the car revving at 2/3 revs. Every track will have a different noise level and they change from event to event. 105db is std on radical race days but I think as a track day you are looking at about 100db. It is not a metric system so 5 db is a hell of a lot. If you phone the track organiser up they will tell you what it is for the said day.
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Old Jan 14, 2010 | 07:52 PM
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Originally Posted by JohnD
Bedford Autodrome was 105 dba @ 75% of max revs. when I was there in 09

JohnD
Yea but they also have towers around the track that take drive by readings. These are normally what kicks off turbo cars which are louder when on boost. Induction noise can be enough to get the black flag there.
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Old Jan 14, 2010 | 08:48 PM
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Bit of a trek, but Im based in jersey, so go to France for track days. I have never been tested, and there were all sorts running well over UK noise limits e.g. a 911 with an open exhaust, my old Mr2 at 104db on tickover etc.

Just a thought- jump on the ferry!
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Old Jan 15, 2010 | 11:25 AM
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Originally Posted by dynamix
Yea but they also have towers around the track that take drive by readings. These are normally what kicks off turbo cars which are louder when on boost. Induction noise can be enough to get the black flag there.
Yep last time I was on track at goodwood I was 104db (105 limit)on the static and I kept tripping the drive by.
I ended up changing up at lower rpm. The sound guy to his credit was v good and was thumbs up or down until I sorted suitable rpm to change up at.
Simon
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Old Jan 15, 2010 | 11:37 AM
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Reading these threads makes me want to get a back box to go tracking.

Bugger

Steve
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Old Jan 15, 2010 | 11:42 AM
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Originally Posted by dynamix
Yea but they also have towers around the track that take drive by readings. These are normally what kicks off turbo cars which are louder when on boost. Induction noise can be enough to get the black flag there.
At Bedford, my 3" decat, std headers and CAI just scrapped in on the static test but easily passed with the circuit sensors.

I can't see any circuit accepting customer sound readings, so its rather academic using your own meter to prove a car will be OK to go on track.
Bedford are happy for cars to be tested in advance of a track day - just ring to arrange a time.
Other circuits do this?
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Old Jan 15, 2010 | 01:18 PM
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Originally Posted by 480bhp.com
Back to the op's question, they measure noice at 45 degrees to the exhaust at a distance of 0.5m and 2/3 or 3/4 max revs.
Thats a bit close isnt it.... its 1m away

Most of the tracks ive been to allow you to book your car in for a sound test before the track day.
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Old Jan 15, 2010 | 01:51 PM
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Originally Posted by Jamz_
Thats a bit close isnt it.... its 1m away

No Not really,

i've done loads of trackdays with very noisy cars, one measured 118db's before i made the changes required to get it through, i've always paid particular attention to the noise levels, there's nothing worse than spending £200 only to removed from the track after 5 laps.

Click this link and check the regs, all TDO's use this rule, but unless you see the tester there with an angle metal stick then the chances are you'll be measured at his guessimate distance.
2010 Track Days Events Calendar - BookaTrack.com
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Old Jan 15, 2010 | 02:13 PM
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Originally Posted by 480bhp.com
More noise limits on this site as well..

easytrack.co.uk > online booking for Silverstone, Brands Hatch, Oulton Park, Spa and many more
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Old Jan 15, 2010 | 04:50 PM
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Once the engine is up to temp properly and not just the water temperature then this will help with your noise loads.
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Old Apr 15, 2010 | 11:59 PM
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Sorry to bump up an old post, but has anyone got pictures of their bungs fitted... Im going to get one made for my car and want to take something to show the guys to make me one.

I was thinking something like maybe a bike can sticking out the back? (mine is the oval magnex back box)
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Old Apr 15, 2010 | 11:59 PM
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Sorry to bump up an old post, but has anyone got pictures of their bungs fitted... Im going to get one made for my car and want to take something to show the guys to make me one.

I've seen some people with track cars that have like a bike can sticking out the back? (mine is the oval magnex back box)

Last edited by Jamz_; Apr 16, 2010 at 12:04 AM.
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Old Apr 16, 2010 | 08:15 AM
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They are only 20-25 new- just get a made one
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Old Apr 16, 2010 | 07:10 PM
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Originally Posted by Grant74
They are only 20-25 new- just get a made one
Not possible when you have a oval magnex back box
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Old Apr 16, 2010 | 08:24 PM
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Use a vice on a round one then

I have also used a decibel insert before- not as effective as a bung, but takes the endge off.

You are talking about Supertrapps or similar above- not worth the cost- just get a quieter backbox
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