HELP - how do I measure my dB reading for a track day?

HELP - how do I measure my dB reading for a track day?

Author
Discussion

Zebede29

Original Poster:

322 posts

172 months

Sunday 21st October 2007
quotequote all
Really fancy taking up a track open day on Sunday next, up at Cadwell Park (I'm only about 15 miles away) but they have a noise maximum of 105dB. Does anyone know if my S2 111S with genuine Lotus Sport stainless exhaust is likely to exceed this and if it's likey, how do I measure it?! Also how strictly do they enforce these limits?

All advice appreciated, thanks!

driving

Edited by Zebede29 on Sunday 21st October 21:41

S Works

10,163 posts

199 months

Sunday 21st October 2007
quotequote all
You should be fine with that.

Zebede29

Original Poster:

322 posts

172 months

Sunday 21st October 2007
quotequote all
So is the 105dB limit very loud then....? The car does get quite loud (very raspy) when on a full-bore acceleration run.

Al D

156 posts

221 months

Sunday 21st October 2007
quotequote all
Every 3dB is literally 'twice as loud', so yes 105dB is twice as loud as 102dB and about four times as loud as 99dB. Cadwell, Oulton Park and the like are therefore almost 4 times as tolerant as Goodwood, Bedford etc (on most days).

They will generally measure you static, at 45 degrees to the exhaust outlet from a range of 1m at 3/4 of max revs ... A standard Sports exhaust on a 111S should be comfortably within but it will depend on the condition age of your can ... and don't forget that your induction system plays a part too.

Good luck! My Caterham R400 often tipped the balance at 108dB; there is nothing more annoying than being black flagged before the warm up lap with nothing more than a £150 credit card slip to show for the day!

Zebede29

Original Poster:

322 posts

172 months

Sunday 21st October 2007
quotequote all
Al D said:
Every 3dB is literally 'twice as loud', so yes 105dB is twice as loud as 102dB and about four times as loud as 99dB. Cadwell, Oulton Park and the like are therefore almost 4 times as tolerant as Goodwood, Bedford etc (on most days).

They will generally measure you static, at 45 degrees to the exhaust outlet from a range of 1m at 3/4 of max revs ... A standard Sports exhaust on a 111S should be comfortably within but it will depend on the condition age of your can ... and don't forget that your induction system plays a part too.

Good luck! My Caterham R400 often tipped the balance at 108dB; there is nothing more annoying than being black flagged before the warm up lap with nothing more than a £150 credit card slip to show for the day!
My car's in very good condition (its only just 3 years old) and has standard induction. Fingers crossed i'd be okay then - but how can they still charge you for a track day if you exceed the noise limit and haven't been out on the track yet?

Cuzza

2,042 posts

202 months

Monday 22nd October 2007
quotequote all
Zebede29 said:
My car's in very good condition (its only just 3 years old) and has standard induction. Fingers crossed i'd be okay then - but how can they still charge you for a track day if you exceed the noise limit and haven't been out on the track yet?
Because they book the track for the day and charge people to use it - they won't have reserves hanging about just in case so they'd lose money if you turn up with car that doesn't meet a condition of the day (that you knew about beforehand).

Assuming you have the CAT in you'll be absolutely fine - in the grand scheme of trackday noise limits, 105 is a loud day. Make sure you ask the noise tester what your car registers, it'll probably be about 96 ish with that setup.

Zebede29

Original Poster:

322 posts

172 months

Monday 22nd October 2007
quotequote all
Cuzza said:
Zebede29 said:
My car's in very good condition (its only just 3 years old) and has standard induction. Fingers crossed i'd be okay then - but how can they still charge you for a track day if you exceed the noise limit and haven't been out on the track yet?
Because they book the track for the day and charge people to use it - they won't have reserves hanging about just in case so they'd lose money if you turn up with car that doesn't meet a condition of the day (that you knew about beforehand).

Assuming you have the CAT in you'll be absolutely fine - in the grand scheme of trackday noise limits, 105 is a loud day. Make sure you ask the noise tester what your car registers, it'll probably be about 96 ish with that setup.
Aaah I see, I thought they were just taking open bookings for the track - didn't realise that the organisers still have to pay the same regardless of the number of successful "runners" on the day. Makes sense now.

I'm assuming the car still has it's cat on - it was bought from a dealer and they MOT'd the car for a year on delivery, without mentioning it not having a cat. I presume if it didn't have one, they'd have told me!!

Just waiting for a trackday insurance quote to come through then I think i'll book it if the figures are ok.

mike_knott

326 posts

173 months

Monday 22nd October 2007
quotequote all
I have a 111S with K&N filter and sports exhaust and I have never had a problem. I think it registers about 96 dB, which is a mile away from 98dB, as Al_D says.

If you are still a bit worried, you could go along to a track day and tell the marshall your situation and I'm sure he'd test you so you could find out.

Alternatively, www.bookatrack.com do noise meter hire for £9 incl P&P both ways.

Mike...

Zebede29

Original Poster:

322 posts

172 months

Monday 22nd October 2007
quotequote all
mike_knott said:
I have a 111S with K&N filter and sports exhaust and I have never had a problem. I think it registers about 96 dB, which is a mile away from 98dB, as Al_D says.

If you are still a bit worried, you could go along to a track day and tell the marshall your situation and I'm sure he'd test you so you could find out.

Alternatively, www.bookatrack.com do noise meter hire for £9 incl P&P both ways.

Mike...
How do you think your 111S relates to track driving, in terms of its power/torque characteristics...?

I'm hoping the torque will be handy on a tight hilly track like Cadwell (where i'm planning to go)

S Works

10,163 posts

199 months

Monday 22nd October 2007
quotequote all
The car will be fine... how's the driver wink

Zebede29

Original Poster:

322 posts

172 months

Monday 22nd October 2007
quotequote all
Driver's fine too....was pounding around Mallory Park track all day Saturday in a Caterham Superlight and got told by the instructor that i'm confident, surefooted, precise and have excellent car control. Oh and it was an absolute riot to boot!!!

drivingdrivingdriving

Vrooom vrooom!!!!

Edited by Zebede29 on Monday 22 October 16:07

mike_knott

326 posts

173 months

Monday 22nd October 2007
quotequote all
Zebede29 said:
How do you think your 111S relates to track driving, in terms of its power/torque characteristics...?

I'm hoping the torque will be handy on a tight hilly track like Cadwell (where i'm planning to go)
As there isn't much of a jump when the second cam kicks in, it is not that difficult to keep the revs in a place where the engine will pull. The biggest problem is its relative lack of power, which results in its low top speed. You can spend a whole lap trying to get close to the car in front through the corners, only to get slaughtered on a long straight. I noticed this is a particular problem at Donington - if you made a bad job of Coppice, it felt like you were going backwards!

That aside, it is very well suited to track use, especially if you get rid of the OEM pads.

Cadwell is a hoot, enjoy!

Mike...

Yee haa!

573 posts

165 months

Monday 22nd October 2007
quotequote all
if it helps my 135R with a pipercross filter and the larini clubsport it registered 93db at 4800rpm stationary so you will have no probs. (db are exponential/log type scale so 105 is massive)

Edited by Yee haa! on Monday 22 October 19:05

Zebede29

Original Poster:

322 posts

172 months

Monday 22nd October 2007
quotequote all
Thats a great relief - thanks all! Next problem is insurance....

R.P.M

1,662 posts

170 months

Thursday 13th March 2008
quotequote all
Hi sorry to drag this thread back up but I am after some info.

I have an S2 exige which has a Stage 2 exhaust fitted, and I am about to fit an ITG induction kit.

Now the problem is that I am planning on doing a few track days in the summer and whilst I love the exhaust (OK maybe a little boomy @ 3k) I'm afraid it may be too loud for even the higher limit tracks i.e 105dbs.

Does anyone have any idea how loud this set up will be? Is the method of test as described above typical of what people have experanced before going out on track? Is there a standard of test or does each track have their own method?
I have access to an apparently very good noise meter but I wouldn't know where to place it and what revs to use for a static test!

Thanks in advance

Rpm

subaqua

891 posts

161 months

Thursday 13th March 2008
quotequote all
As mentioned before, the standard STATIC measure is tested like this:

They will generally measure you static, at 45 degrees to the exhaust outlet from a range of 1m at 3/4 of max revs ...

So for K series cars thats typically 4.5k.. on yotas 6k (although I have heard people with yotas occasionally get confused and perform the test at 4.5k smile

The stage 2 is quite loud and adding a non-standard induction wont help, but you have to be pretty damn loud to fail a 105db satic test.... i.e. Randys race S/C honda exige ran in a 105db day at Oulton last year.... and some people (well SimonK anyway) said my S1 with decatted Janspeed supersport exhaust and a piperx induction is louder than Randys (mine was 100db at Brands a week ago).

I see you are in the Midlands, I thin yur best bet would be to get alng to an MSV or LOT day at Donnington, or maybe Silverstone next Monday and get them to do a static test for you. It'll give you an idea of whether you have loads of room for comfort, or whether you are getting close to limit and you can consider the induction change in this light.

Oh... you also need to bear in mind that other environmental factors affect the result of the test - whether the car is fully warmed up for example, whether its raining, if its a crisp, cold sunny morning. Pretty much every time you get the car tested, you'll see a slightly different figure