whats bedford like with noise?

[matt 2LT]

im about to book a open pit day at bedford on the gt track.

but would like to know what they are like with noise?

all i know is that the limit for the day i will be going is 100db.

will this be just static? or will it be drive by aswell?

cheers,
matt

Edited by matt 2LT on Sunday 28th June 11:22

[flemke]

matt 2LT said:

im about to book a open pit day at bedford on the gt track.

but would like to know what they are like with noise?

all i know is that the limit for the day i will be going is 100db.

will this be just static? or will it be drive by aswell?

cheers,
matt

The actual issue is drive-by. There are microphones, located at a few places around the track, that give direct readings to the council. If the council's screen indicates that a certain threshold has been exceeded, they become very agitated.
Bedford uses a static test (100dB) as a filter to assess whether a car is likely to breach the drive-by threshold. Some cars will pass the static but subsequently breach the drive-by, which will get them taken off the circuit. Others will fail the static but would not breach the drive-by and thus not bother the council.
If your static is well over the limit, they won't let you on the circuit. If it's marginally over, they may let you on because it is possible that you wouldn't breach the drive-by.
Their policy is that, if during the actual track-day you yourself breach the drive-by once, you may not take the car on the circuit again that day. Upon request, however, they will give your car a drive-by test (done after driver's briefing) to see whether you're going to have a problem. If it fails this test, the car is not barred, but you'll have to figure out how to deal with the problem before you take it out and do get barred.

Edited by flemke on Sunday 28th June 22:26

[mrmr96]

Turbo cars can often pass the static but fail the drive by. This is because the engine is not under load during the static test so is not generating boost and therefore air flow volumes are lower. Under load on a track the turbo will produce full boost and a massive increase to the volume of air and hence the volume of noise produced.

Flemke is right about the 1-strike and you're out policy. I've been black flagged for noise on my 4th lap before. Go directly home. Do not pass Go. No refunds. Arse.

[fivesixseven8]

If you have the standard exhaust on your car still you will be fine. I was there a few weeks ago and everyone sailed through.

[PetrolTed]

fivesixseven8 said:

If you have the standard exhaust on your car still you will be fine. I was there a few weeks ago and everyone sailed through.

Err... sorry, no. Depends on the car. I no longer go there as it - literally - depends which way the wind is blowing

[fivesixseven8]

PetrolTed said:

fivesixseven8 said:

If you have the standard exhaust on your car still you will be fine. I was there a few weeks ago and everyone sailed through.

Err... sorry, no. Depends on the car. I no longer go there as it - literally - depends which way the wind is blowing

If his profile is correct then it's an Astra, I'd have thought that would be fine? An RS like your's is a totally different kettle of fish I agree.

[PetrolTed]

Ah, sorry - I misintepreted what you were saying. You're right.

[matt 2LT]

yes its an astra 2L turbo with around 300 bhp,and has a miltek cat back exhaust, and there is no pre-cat.

i would say it should be under 100db, but i don't wan't to end up exceeding it on 1 lap and getting sent home.

and i don't really know what 100db sounds like.

but if i can try a drive by before the session starts then that would be good, and if it fails, i will just have to keep the revs down.

[flemke]

matt 2LT said:

yes its an astra 2L turbo with around 300 bhp,and has a miltek cat back exhaust, and there is no pre-cat.

i would say it should be under 100db, but i don't wan't to end up exceeding it on 1 lap and getting sent home.

and i don't really know what 100db sounds like.

but if i can try a drive by before the session starts then that would be good, and if it fails, i will just have to keep the revs down.

You sometimes have to request this test. If on static you're over 100, they may require it.
A couple of tricks to stay on the right side of the static threshold:
- during the test, keep the clutch disengaged throughout, and
- during the test, bring your revs up slowly. If you bring them up too far and then have to ease off, the tester can see a peak reading on the meter for an engine speed above the test requirement.
Also, I don't know a lot of people who, when instructed to take the revs up to 4500, necessarily take them up to exactly 4500. One of the Bedford staff will probably watch to see that you're not taking the mickey, but if you're within a couple of hundred it's usually considered to be close enough.
Regardless of whether you pass the static with plenty to spare, you may want to ask where the microphones are. Two or three cars going past simultaneously can trip the alarm bells back at Petty Bureaucracy Central, even though none of them individually was over the limit. Knowing the noise-critical spots, you can avoid finding yourself amongst a cluster of cars at the wrong time.

[fivesixseven8]

matt 2LT said:

yes its an astra 2L turbo with around 300 bhp,and has a miltek cat back exhaust, and there is no pre-cat.

In that case I wouldn't be too confident. Maybe try a few of the Astra/VX forums to see if someone else with a similar setup has done a noise test before?
I'd err on the side of caution and try somewhere with a much higher noise limit first. A noise test is a noise test so at a minimum you will know your static value.

[flemke]

fivesixseven8 said:

A noise test is a noise test so at a minimum you will know your static value.

I'm not so sure about that. I've got readings on the same car that were as much as 4dB apart. Even if the operator and instrument are constant, the wind, air temperature and humidity all have an effect.
I've been told that some makers of sports cars get past the EU noise regs by having their cars' exhuasts type-approved at a hot and dry site in Spain.

[fivesixseven8]

flemke said:

fivesixseven8 said:

A noise test is a noise test so at a minimum you will know your static value.

I'm not so sure about that. I've got readings on the same car that were as much as 4dB apart. Even if the operator and instrument are constant, the wind, air temperature and humidity all have an effect.
I've been told that some makers of sports cars get past the EU noise regs by having their cars' exhuasts type-approved at a hot and dry site in Spain.

Thanks, I stand corrected.

[Wh00sher]

If you live nearby, call in and ask them to test it on driveby or static. I did that when I wasn`t sure what my Golf would be like, they would rather you do that, than turn up and have to be sent home.

If they aren`t local, ring your nearest track, as far as I know, they will all happily noise test if you are unsure.

[jon-]

Bedford will test your car for free if you're local (which I am). Just give them a call, they'll arrange a time (usually weekday morning) and someone will do a few drive bys. It's better than wasting £200 being thrown off after 2 laps, also nice to see your car doing a few laps

To add to flemkes' tips, a warm exhaust is usually quieter than a cold one

[Ponk]

flemke said:

matt 2LT said:

yes its an astra 2L turbo with around 300 bhp,and has a miltek cat back exhaust, and there is no pre-cat.

i would say it should be under 100db, but i don't wan't to end up exceeding it on 1 lap and getting sent home.

and i don't really know what 100db sounds like.

but if i can try a drive by before the session starts then that would be good, and if it fails, i will just have to keep the revs down.

You sometimes have to request this test. If on static you're over 100, they may require it.
A couple of tricks to stay on the right side of the static threshold:
- during the test, keep the clutch disengaged throughout, and
- during the test, bring your revs up slowly. If you bring them up too far and then have to ease off, the tester can see a peak reading on the meter for an engine speed above the test requirement.
Also, I don't know a lot of people who, when instructed to take the revs up to 4500, necessarily take them up to exactly 4500. One of the Bedford staff will probably watch to see that you're not taking the mickey, but if you're within a couple of hundred it's usually considered to be close enough.
Regardless of whether you pass the static with plenty to spare, you may want to ask where the microphones are. Two or three cars going past simultaneously can trip the alarm bells back at Petty Bureaucracy Central, even though none of them individually was over the limit. Knowing the noise-critical spots, you can avoid finding yourself amongst a cluster of cars at the wrong time.

The only problem with that is by tricking the static at Bedford you could end up losing out due to the drive by meters. If they black flag you for noise then you're going home. However if you fail the static then that gives you a chance to sort a bolt on silencer or exhaust bung.

Good advice for other tracks though.

Also I don't think the readings go to the council, they do have a noise room where the meters are monitored from though which is due to council imposed limits.

[mrmr96]

Ponk said:

I don't think the readings go to the council, they do have a noise room where the meters are monitored from though which is due to council imposed limits.

The chap there told me that they are linked to the council so when the alarm goes off trackside, it goes off in the council too and it's logged. After a weekend the council sends a list of 'triggers' to the track and asks what the car was and what action was taken.

Any action other than "car sent home" is apparently not acceptable. Presumably in case the same car trips it twice in a day - in which case the council will quite rightly want to know why it was allowed back out - putting the TDO's license at risk.

This ofcourse might be bull, but that's what they are telling people.

[Mark T]

well...I passed the static, just, after 2nd attempt - twin exhaust - they said 104 (!) on one & 98 on other which they 'averaged' at a pass which I was v happy with but was then very worried about the drive by test.
Had a good day & forgot about it, so afaik never triggered it so all was well !
Mr2 turbo 3" straight through with big turbo etc - quite loud !
So I would say it's pot luck depending on wind direction, conditions, however it was a pretty windless day...
I would go again & take my chances.
Mark

[chevy-stu]

matt 2LT said:

yes its an astra 2L turbo with around 300 bhp,and has a miltek cat back exhaust, and there is no pre-cat.

i would say it should be under 100db, but i don't wan't to end up exceeding it on 1 lap and getting sent home.

and i don't really know what 100db sounds like.

but if i can try a drive by before the session starts then that would be good, and if it fails, i will just have to keep the revs down.

You can buy a cheap DB meter from somewhere like Maplin or on ebay and do the test yourself (with a friend keeping the revs up) in a similar manner to the one they will do at the track, just to give you a rough idea of your noise reading.

http://www.maplin.co.uk/module.aspx?moduleno=46362

http://cgi.ebay.co.uk/Mini-Digital-Sound-Level-Noi...

[teepee41]

in short strict!

have a friend who got black flagged in a standard Gallardo, which whilst loud still seems absurd as he could have just left the track and gone and annoyed the locals on the road instead.

Best not to risk it.

[Johnny Rocco]

anonymous said:

[redacted]

That was me. I didn't get black flagged but I got a few talkings to that we were within a smidge of tripping the meter.

A marshal told me an interesting thing. He reckoned we should avoid running in close formation with other cars but especially other Porsches as if the engines/exhausts have a similar frequency, it's more likely to trip the meters. Don't know how true this is.

The car is standard but it is quite loud. Ended up shortshifting/tiptoeing past each of the four microphones which took the edge off the enjoyment a little.