Bedford Noise Limits - Static v Drive By

[topcarrera]

I have an older (84) air-cooled 911 that I have driven at several Bedford trackdays the last of which was about 2 years ago. My car (unchanged since last Bedford visit) has a standard exhaust and induction system except for a "mild" rear muffler. Noise wise it is only a tad louder than a standard car but I am right on the nominal 101 db static limit for Bedford.

Previously when I have arrived at Bedford the noise testers have greeted participants on the approach road to the circuit itself. On some occasions my car has been noise tested on others the officials have waved me through and simply muttered "no problem", obviously making an intuitive judgement that the car will not cause a noise issue. When I have been noise tested I have always been found to be right at the 101 db limit or even a smidge over although never more than 102 db. On the occasions where I have just broken the 101 db limit the testers have told me the result but (without prompting) then told me that the drive by test is the critical requirement and that I was unlikely to have a problem with that. Usual older 911 scenario - noise testing an aircooled rear engined car with the mic just a couple of feet away from the engine as well as the exhaust!

Given that my car is at 101/102 static I have always struggled to understand how some of the other seemingly far more noisy machinery at each of the trackdays that I have done at Bedford has survived the noise testing.

I understand that Bedford have had to tighten up a little bit in the past eighteen months or so. My question is as follows -

Do I now stand any risk of being sent home if my car fails the static test by 1db even if there is virtually no realistic prospect of the car exceeding the drive by limit? Whats the latest approach being adopted by the officials at Bedford?

[Chris71]

Interested to hear the verdict on this from someone who knows, but my conjecture is that you'll be lucky to get through if it fails either part of the test. I'm told they can be quite strict?

[mrB10]

I've heard they are strict and throw you off, maybe a call direct to Bedford would clear that up?

[topcarrera]

mrB10 said:

I've heard they are strict and throw you off, maybe a call direct to Bedford would clear that up?

I think that certainly is the case if the drive by limit is exceeded - that is not a concern for me.

My question is whether there is any pragmatism adopted by the officials for VERY minor infringements of the 101db static limit if there is strong reason to believe that the drive by limit will not be exceeded - This certainly used to be the case.

As far as I understand the drive by noise limit is what the organisers are bound to enforce and I suspect that the static limit is simply a self-imposed measure to prevent cars likely to exceed the drive by limit out onto the circuit in the first instance. Given the rear engined layout (microphone from noise test picking up engine clatter as well as exhaust noise) an air cooled 911 nudging just over 101 db static is very likely to be quite a bit quieter on the drive by measure than many front engined cars with slightly lower static noise

[Chris71]

Again, it's conjecture, but I suspect it depends on the guy doing the noise test. It's, ahem, not completely unknown for them to show some discretion but I really, really wouldn't bank on it.

[Munter]

I've been this year.

Yes they test everybody static. However. They are monitored by the council on the Drive by noise. So if you think your car will fail (or has failed) the static test you can adjust your car and be re-tested or talk to the organisers and they might arrange a drive by test with a marshal for your car.

IF you fail during the day on drive by having passed the tests earlier you'll be chucked off. (e.g. theres no point being deliberately quiet on a drive by test)

The key here is A)Take bolt on silencers if you can find them for your car. and B) Talk to the organisers/site before the day or right at the beginning of sign on.

[NickXX]

It's the drive by test that matters as it's linked to the Council offices.

I think there is a bit of discretion shown for the static - and they can do a drive by test for you before going out on track if you request it now.

[mrmr96]

Munter said:

IF you fail during the day on drive by having passed the tests earlier you'll be chucked off.

I can confirm from personal experience that this is true. (My turbo car passes static test no problem as the engine is not under load and so doesn't generate the same boost as it does on track. So passed static and was then black flagged and sent home for breaching the drive by on my 3rd lap. No refunds. Arse.)

[Rusti Evo]

Yes, turbo cars are difficult - pass static - fail drive by.

Goodwood is just the same.

[Porkie]

Things are MUCH tougher at Bedford now...

They will still let you on though if you fail the static. Its the drive by thats important.

and you will NOT get a second chance if you fail the drive by on track. You are off. No second or third chances any more... even if you know the testers really well!


You can however transfer to another car. So all is not neccesarily lost.

My 996TT walks through the static but can ping the drive by somedays as Bedford. (my Boxster is opposite. Fails static, no worries on drive by) With the 996 it all depends on wind conditions on the day believe it or not! oh and also DON'T get to close to other cars near the noise meters. This can affect it somehow I have been told.

[flemke]

Munter said:

The key here is A)Take bolt on silencers if you can find them for your car. and B) Talk to the organisers/site before the day or right at the beginning of sign on.

C) Lift whilst going past the microphones.

[Munter]

flemke said:

Munter said:

The key here is A)Take bolt on silencers if you can find them for your car. and B) Talk to the organisers/site before the day or right at the beginning of sign on.

C) Lift whilst going past the microphones.

In the long run though if people keep doing that because their car is over the drive by noise limit the locals will continue to complain and get even lower limits imposed.

Like it or not. The lunatics are running the asylum. As time progresses we're going to have to decide between driving on track in quiet cars, or not driving on track at all. And it's not just Bedford is it.

[red griff roger]

Munter said:

Like it or not. The lunatics are running the asylum.

You are not kidding. I live close by Bedford, and well remember the debate over whether to use the runway as an air freight terminal. As we all know, airplanes don't make any noise do they? Just like Donnington.

[Chris71]

red griff roger said:

Munter said:

Like it or not. The lunatics are running the asylum.

You are not kidding. I live close by Bedford, and well remember the debate over whether to use the runway as an air freight terminal. As we all know, airplanes don't make any noise do they? Just like Donnington.

What takes the piss more is when the venues have been there a lot longer than the local residents - or even their houses. I used to race karts at an airfield which had been in continuous use since the war, if not before then, and the residents of a new part complete housing development were already complaining about the noise.

I know it's not a new point but it strikes me as unbelievably stupid. It's like moving to Paris and complaining it's full of the French.

[LMP]

You can have a drive-by noise test before the trackday if you are worried. Call MSV or Bedford Autodrome to arrange it.