Brands Hatch noise limit and 997.1 GT3

Brands Hatch noise limit and 997.1 GT3

Author
Discussion

simon clark

Original Poster:

306 posts

247 months

Sunday 14th December 2014
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Evening all,

Just wanted to provide a word of warning to those with GT3's intending to track them at Brands Hatch. I was there on Friday and was immediately black flagged for noise so I turned off the sport mode and same thing again.

Their noise meters were showing 94db on the drive-by and the limit is 92db...

It was very odd as I've probably been there half a dozen times this year in the car, which is totally standard and only made 100db on the static (limit is 105db) so I was pretty miffed. Others were being flagged too, a number in ClioSports with fruity exhausts. The day I can't take a standard GT3 on a trackday at Brands Hatch is a worrying sign of the times.

Anyone else found issues recently?

Cheers

Simon

RKi

307 posts

129 months

Sunday 14th December 2014
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Hmmmmm worrying. I'm going there on Friday hopefully in an evo with a loud exhaust. Says on trackdays.co.uk 105 db though? Maybe wind direction contributes.

QBee

20,904 posts

143 months

Sunday 14th December 2014
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The clue is in the number of cars black flagged. Atmospherics play quite a big part in noise level tests.

On the static test my TVR can be anywhere between 99 and 109 decibels. I never know before I arrive at a track.

I failed the 101dB static test at Bedford earlier in the year (I was 103), as did about 10 other cars including Petrol Ted's GT3 (also 103, measured by the driver's door in a even attempt to pass him!). In the end we were all allowed through due to the high number of failure and our protests, and none of us failed the 87.5 dB drive by limit.

I don't know how they can solve this......but as we are a fair part of their income they need to find a fair way of resolving it I think

I am not going to Bedford again until they do.

PS I was 102 at Brands two weeks ago with no bolt on cans, one of my lowest readings.

Henry Fiddleton

1,581 posts

176 months

Monday 15th December 2014
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I was at Brands yesterday, and my stock Mx5 did 94db!

I even jokingly said its gained 6db from before (numerous other times).

So maybe something strange going on with the equipment or the its something in the air!




V8 FOU

2,970 posts

146 months

Monday 15th December 2014
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I was black flagged at Goodwood on Saturday. Problem for the Bentley is the RH side exhaust. Does 96db static, but was "well over" on drive by at the pits. All the other checks were on the outside of the track so probably didn't hear me!
Going to look at a spare rear exhaust with rear exit I think.

I think it might be a good idea to see if/when the sound meters are calibrated and to what standard?

GT3-RS

1,085 posts

218 months

Monday 15th December 2014
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I've given up doing Car Trackdays now it's just a complete waste of time it looks as though the Noise Police have won......I guess the the local councils want people to race on the roads cause that's what they're going to do if they can't get on Track.....typical mental councils run by the ever increasing Tree hugging PC popularity vote grabbers.....Furkin Losers......Grrrr

anonymous-user

53 months

Monday 15th December 2014
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I just did some reading and apparently in very humid conditions noise is transmitted more easily, wind direction also has a big impact. Additionally if the ground is cold and the air above it is warmer then more noise is transmitted horizontally rather than upwards.

The document I was reading was suggesting differences in readings varying by 10 to 20dB is perfectly possible. I knew the conditions had some effect on noise levels, but I'd no idea it was that much.

The ground was very cold, it was very humid and also pretty gusty at Brands on Friday - I guess that was the cause of the high noise readings.

Either that, or their meter was completely screwed. biggrin

Good to meet you on Friday BTW Simon, I was in the (also black flagged) Clio in the garage next door.

The info I found is here:
http://www.mne.psu.edu/lamancusa/me458/10_osp.pdf

Raify

6,552 posts

247 months

Monday 15th December 2014
quotequote all
Interesting, both on the weather side of things, and how often and accurately the equipment is calibrated.

I measured 87 on friday, in a car that's measured 83 on every other trackday I can remember getting a reading.

Since dB is a logarithmic unit, it's even more important to have an accurate reading under consistent conditions.

Not much they can do about the weather, but they must have realised something was wrong when they black-flagged about 10% of the customers, most of whom had standard cars.

Sigmamark7

314 posts

160 months

Monday 15th December 2014
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I gave up with my GT3 after a pointless trip to Goodwood where it measured 106dB in normal mode! Heaven only knows what it would have been in sport mode. I bought a Clio 182 with a Miltek exhaust which passes noise tests everywhere despite sounding loud and a Radical SR3RS, which fails noise tests everywhere despite sounding quiet - despite having had a specially built twin silencer system made up!
The Radical loves trackdays, because it gets a ride out on the trailer, gets taken off the trailer and lovingly warmed up, taken to see the noise tester, then put back on the trailer and taken home. The only exception to this has been at Donington, where it didn't trouble the drive by meter all day!
So thanks to the difficulties with noise and in particular, the very random results from different venues, the GT3 has gone, the Radical spends most of its time in the garage and the Clio is getting mercilessly flogged all over the place!

Far Cough

2,192 posts

167 months

Monday 15th December 2014
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Yep, spent all day last Monday blasting round and only got black flagged 10 minutes to the end when the evening air had got thick and dense.

f1_dragon

310 posts

223 months

Monday 15th December 2014
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I was there on 2nd December, wet day with low mist/drizzle, not sure if that played a part.

I failed the static coming in at 109dB. I have a 996 C4S with a standard PSE. Odd as I have previously been to Bedford and Silverstone with no issue, with Bedford particularly having much more stringent limits.

I managed to pass later on in the AM with some 'optimization of throttle modulation' during the re-test...

Far Cough

2,192 posts

167 months

Monday 15th December 2014
quotequote all
The standard noise test has got to change and it has been shown time and time again to be , inaccurate ,unfair and outdated. It makes no difference whether your car is rear engined , turbo`d or naturally aspirated with a large airbox on ala csl. All these cars make noise differently when on the move to a static position.

What makes me laugh is that the majority of the cars that are failing are perfectly road legal and too new to warrant an MOT. So , you could quite legally spend all day ragging up and down outside the circuit on the public highway bit not 50 yards into the venue on the purpose built circuit - madness. I cant imagine that the take off noise of a fully laden 747 will creep under 105db`s as it flys straight over Donnington for example and dont get me started about Mr Palmer landing his helicopter on the banking of clearways. I bet he doesnt get black flagged on landing !

gruffalo

7,509 posts

225 months

Monday 15th December 2014
quotequote all
Raify said:
Interesting, both on the weather side of things, and how often and accurately the equipment is calibrated.

I measured 87 on friday, in a car that's measured 83 on every other trackday I can remember getting a reading.

Since dB is a logarithmic unit, it's even more important to have an accurate reading under consistent conditions.

Not much they can do about the weather, but they must have realised something was wrong when they black-flagged about 10% of the customers, most of whom had standard cars.
Interesting the range of readings from the same cars, 3dB is a doubling of the sound pressure, so your 4 here is more than twice as loud.


Henry Fiddleton

1,581 posts

176 months

Monday 15th December 2014
quotequote all
Very interesting reading.

I was going to get a new S/S exhaust for my car as the stock one is on its last legs.

Not sure I will bother now!

mad4amanda

2,410 posts

163 months

Monday 15th December 2014
quotequote all
Hi folks, just to be clear static noise tests will vary according to the weather and as noise testers we do take account of this humidity and temperature do make a difference but we know this and allow for it but this may explain a slightly higher reading from one day to the next.
However I happen to know the OP triggered the drive by meters (all of them by several Db) because it was I that recorded the triggers and that spoke to him. Even taking account for the conditions it was over, the meters are located both sides of the track at several locations and so take account of any wind carrying the sound.
They do however of course measure total noise not just exhaust so exhaust plus induction. We do ensure that cars are monitored throughout the day
This Model (note not this car) of GT3 does have a history of failing drive by at a number of venues often in relatively "standard" spec. something that may unfortunately limit its use if not addressed.
I believe the black Clio on the day had a decat and silencer delete and did have an issue complying as a result.
Unfortunately noise is an issue for all of us to address, and I perceive this will continue to be an increasing pressure on us all. The circuit invests in technology and training to monitor and flag up issues this is to protect the future of the venue and allow its use to continue.
To put all this into perspective out of 60 cars that day we had issues with 4 on drive by all of which were dealt with, on Saturday(40 odd cars mainly lotus) there was just 1 race car that was resolved by fitting a baffle and no issues on Sunday as I recall (50 cars).
I do remember that there was a mod for the GT3 (Not sure if this was for the same model though as cant find it now) that involves a mod to the hoses on a solenoid that would limit the opening of the valves on the bypass section of the exhaust but cannot find it via google at the moment it might be worth investigating? it was temporary not permanent so was reversible not sure if there are any warranty implications though.
found a thread that points to it maybe?
http://www.pistonheads.com/gassing/topic.asp?t=109...
HTH

anonymous-user

53 months

Monday 15th December 2014
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Interesting post, thanks.

Do you know how many Clios were black flagged on Friday for noise limits?

mad4amanda

2,410 posts

163 months

Monday 15th December 2014
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from memory 2

Stephanie Plum

2,776 posts

210 months

Monday 15th December 2014
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I've always wondered why the MSV tracks (bar Bedford) have a consistent drive by of 92db whether you're on a 98, 101, 102 or 105db event? How does that work? At Goodwood for example, where people often slag off the noise restrictions, the drive by is higher on 105 days than 98 - why aren't the MSV tracks the same?

Not having a go btw - genuinely interested.

_Neal_

2,658 posts

218 months

Monday 15th December 2014
quotequote all
Raify said:
Interesting, both on the weather side of things, and how often and accurately the equipment is calibrated.

I measured 87 on friday, in a car that's measured 83 on every other trackday I can remember getting a reading.

Since dB is a logarithmic unit, it's even more important to have an accurate reading under consistent conditions.

Not much they can do about the weather, but they must have realised something was wrong when they black-flagged about 10% of the customers, most of whom had standard cars.
Something going on with the meters at Brands - my (quiet-exhausted) Caterham was reading 4-5 db higher than usual on a trackday there in the Autumn on the static test. Most of my trackdays are at MSV circuits, and the Caterham hasn't got any noisier over the past year. Weird. Would meters go out of calibration over a long season?

gruffalo

7,509 posts

225 months

Monday 15th December 2014
quotequote all
I think it will depend on the restrictions put on the circuit by the local authority who are lobbied by local residents who move next to a circuit and then complain about the noise.

The circuits have to monitor the noise and I believe to be able to report to the local authority of get closed down.

Goodwood have a live link to the LA from the 3 green boxes round the circuit, they have a certain average noise level that they are mandated to operate within, this is why they control the numbers on the circuit at a time. I know of a local resident who lives in Lavant and is about the closest house to the circuit, he can't hear anything but the LA have their power and are determined to use it, or so it would seem.

This is all what I have been told by the way but I was told this by people who should know.