Track Day Sound Test?

[Young Pretender]

I'm about to book my first track day at brands hatch but I'm concerned over the 105db limit. I've no idea where my car is in terms of this limit but I think it's quite loud.

They said I can pop down to an earlier session for a test before I book but I missed the sound testers on the eve session I visited.

My question is: if I fail the test on the day are there any measures I can use to reduce the noise short term? To get me through a retest.

Thanks

Mark

[Tom Frankland (T3OMF)]

You can get this kinda thing, im sure you can get cheeper ones

[GreigM]

What engine have you got? Most cars should be well below 105 except bike engines.

As for measures you can do:

• Repack your exhaust (if repackable)
  
• When asked for your rev limit lie to the marshalls
  
• I've lined my bonnet with sound insulating materials (often its the induction causing most of the racket)
  
• Build an airbox around your intake
  

Aside from that little you can do - you can buy bolt-on silencer tips etc but I've no knowledge of how well they work and have heard bad things about performance and effect on engine from using them.

[XTR2Turbo]

Be careful with Brands as I think a Palmersport venue.

If like Bedford they are very happy to test you before but if you turn up and fail the sound test they won't let you on and won't give a refund.

Also if you trip a sound meter they will probably black flag you and send you home. So don't risk if marginal.

[Young Pretender]

It's a 2l zetec, 45 webber carbs, pipercross open air filter and not sure on exhaust.

So am I right in understanding then, that Palmer motorsport venues do not only test at the beginning of the session but continually throughout? Definately the case at brands?

Maybe I'll just take a chance but I'll be hacked off of they send me home.

[GreigM]

Most circuits tend to test you initially as a "static" test - that'll be where the 105db comes from. Generally unless you have a car which is significanlty louder under load (some of the turbo'd cars suffer from induction roar) then the "drive-by" throughout the day won't be an issue.

I bought one of these and found it to be fairly accurate for this kind of thing:

http://www.amazon.co.uk/Silverline-633937-Sound-Level-Meter/dp/B0015NSTLI/ref=sr_1_2?ie=UTF8&qid=1338473105&sr=8-2

Probably cheaper than a drive to the circuit!

[Pistol Pete]

105db is loud so would have though you should be ok, think brands and bedford are different re sound as is just a static test in the morning. Think bedford is strictor due the modern plannin permission hoops.

Make sure your engine is warm up and position your car so there is nothing (buildings, cars etc)behind your exhuast exit that the noise can be bounced back from.

If you can get to essex, I believe smokey has a sound meter you could ask to borrow.

[Young Pretender]

Thanks for all the advice it's been really usefull. GreigM that sound meter is very cheap!

I've decided to, ahem, work at home next Thursday and pop down to brands again before I book an end of June session.

Good tip about positioning the car away from buildings :-)

[GreigM]

also, if you can turn your silencer I hear pointing it towards the tarmac can help

[XTR2Turbo]

It depends upon the venue.

Bedford has sound meters that apparently relay data back to the council directly. Hence why Palmersport are so strict.

I'm not sure about brands having track wide metering.

[steve bain]

if you or anyone has a smart phone like an iphone download the db meter app. its accurate and free.

[Young Pretender]

if you or anyone has a smart phone like an iphone download the db meter app. its accurate and free.

That's a good idea thanks.

Are static measurements taken with the meter right next to the silencer and then at a certain distance?

[adam1330]

The Surrey area has a sound meter, not sure who looks after it but it says on the Surrey area forum, someone might be able to bring it along to the next meet.

[s2rrr]

Noise tests at Oulton taken about a metre diagonally back from the silencer outlet same as IVA ish. They also have on track monitors.

Bob

[kevip6]

I don't think Brands has metres around the track and it's just the static test. I didn't have any issues at brands a couple of months ago but they didn't do the static test on mine. They have details on the sound testing on the web site, think its 0.5m up and 0.5m away from the exhaust and read at 45 degrees up from the exhaust outlet at 3/4 max revs. Just fib slightly on the max revs as well