Noise testing at Snetterton race meetings

[avro]

When it comes to noise testing Oulton Park is the worst, our super tourer passes all circuits noise tests with the exception of Oulton, and the noise tester is not known for his flexability, I hope he is no longer there as we are racing at Oulton in Sept !!!!!

[Al Weyman]

Well after my adventures at Rockingham today with the noise meter (less said the better because I am already in hot water) I am going to take out the V8 and install an electric motor then with the forthcoming threat of Hans requirements and all the other safety things that keep coming forward why don't we take it a stage further and stick a remote contol in the car and race it from the stands by radio control like model car racing.

This is the perfect answer, the enviromentilists will be happy (or at least those that want to redevelop the surrounding land for housing or see their properties soar in price when the nasty circuit is shut down), the Health and Safety will be happy, everyone (apart from the paying public and more paying driver) will be happy. If this carries on we may as well all pack up and go home.

[MG Racer]

Al,

There were some issues regarding noise levels a The Rock today and I just dont understand how inconsistent it can be. A car passes at another ciruit and is at 105 or below and with no changes it suddenly doesn't pass.

This is a similar situation to scrutineering. A car passes one week and is not changed, altered or anything and then at the next race suddenly there is something that is not right with it. Surely there must some way of getting consistency?

Anyway I had a good day today at Rockingham and got her home in one piece so thats the main thing, apart from a dogey starter motor that packed up for some of the day.

[Al Weyman]

This is become a real pain now. Back to the drawing board! Oh and nice to meet you MG Racer.

[phatgti]

I thought this worked well at snetterton yesterday, no hold ups.

Wayne

[Chris Y]

Was this with the new(er) twin exit system, Al ?

[Al Weyman]

Yes it was Chris, I very disappointed as it was a lot of hard work fabricating that set up and messy work I just do not like doing, I am running out of ideas now as I have a bit of a chassis clearance problem and really need to run side exiting as that I think is the only way I can get it down such is the vaguries of this sound testing thing, I am sorry I am not convinced with this system of measurement at all as the car quite simply is very quiet on the track with absolutely no induction roar, especially compared with some.

[DaveW]

Originally Posted by phatgti

I thought this worked well at snetterton yesterday, no hold ups.

Wayne

Thanks for the feedback Wayne. We will continuing trialling it at the next BRSCC meeting on the 8/9 July.

[jonners]

Originally Posted by Al Weyman

Yes it was Chris, I very disappointed as it was a lot of hard work fabricating that set up and messy work I just do not like doing, I am running out of ideas now as I have a bit of a chassis clearance problem and really need to run side exiting as that I think is the only way I can get it down such is the vaguries of this sound testing thing, I am sorry I am not convinced with this system of measurement at all as the car quite simply is very quiet on the track with absolutely no induction roar, especially compared with some.

Do you know if you get caught out on the bit where you're holding the revs at the specified level or on the over run as you lift off??

I'm not sure if the sound scrute is required to measure the over run as well but I have noticed that there is a technique at some venues where you don't lift off until the scrute has nodded - avoids those nasty pops and bangs, and especially resonances which can send the reading through the roof

I know developing a special technique to get a noisy car through isn't on but sometimes the cars that seem to fail the noise test aren't the ones you expect

[graham bahr]

sometimes a car will do better at a noise test if tested at higher rpm so as to avoid the pop pop bang off load spot, i used to struggle a bit with noise at goodwood until i stopped giving a conservative max RPM.

i did well at coombe i got noise tested 3 TIMES! passed all three, prior to coombe i either sailed through noise or was meassured at 105/106
before going i added an extra silencer, an identical one to the 2 previously fitted, the car is very noticably quiter when left running in the paddock, at coombe i tested at 104/105 which doesnt seem much of a reduction, considering how much quiter it actually is, not that it was ever noisy on the driveby

[AW64]

my noise test went up 2db at coombe from sat to sunday dont no why

[R59]

The noise test meter was 2dB closer to the centre axis of the chimney's exit, ie: not quite at 45deg. That's a guess.

There were issues at Rockingham where people failed the test with one meter, but passed with another. Both were calibrated.

I know that the battery level in the calibrator that came with my meter is quite critical. If the battery is left too long, I have found that it's level drops off by a couple of dB, and that's the difference between a pass and a fail on a race car. I know this because a new battery brings the level up.

Rob.

[Al Weyman]

Anyone tried these new generation of sound reflection Spiral Flow mufflers. Spintech, Moroso (my favourite company, I must have bought half of it by now!) and Edelbrock are all doing them. They use them in the States at circuits they have sound problems with, I am thinking of trying a pair of Moroso Spiral Flows from Real Steel as I think my Joe Elliss straight through absorbsion mufflers can no longer cut it and OK the Supertrapps get the sound down well and when I used two instead of the one at the Rock did not seem to effect performance so much but they just sound, well for want of a better word, like a wet fart (can I say that here?) and they look ridiculous.

[Woolley]

Originally Posted by Al Weyman

they just sound, well for want of a better word, like a wet fart (can I say that here?)

Apparently you can. I'm quite glad, actually because it's a wonderfully descriptive term, although somehow I can't imagine that your car could sound other than lovely going by the pictures. I must make sure I become acquainted with the real thing fairly soon.

Since we're wandering around the subject here, I might eventually split this into it's own thread, but I'd like to ask a controversial question: Why does club motorsport have to be noisy?

Now I personally don't have a problem with that. On the whole I like the noise motorsport makes, and a good rorty V8 (or a certain Ferrari sports car with a flat 12) is soul stirring stuff. I might draw the line at F3 and quite a few of the one-make type things, though. However, for our neighbours it's unpleasant, in much the same way I get irritated by next door's television sometimes, or a former resisent up the road who wanted to sit in his garden in summer listening to rock music, which was being played on the monster system in his front room. He liked it, I didn't.

Why not just silence everything, but allow a bit of lee-way? Set it at 80b, for instance, but allow a small percentage of error, and note it on the scrutineer's record so that it can be gradually brought down over a few meetings. It also means you can hear the commentary. I'm told with some circuits that's the bit that annoys the locals, and if the cars were quieter, the loudspeakers could be too.

Discuss...

[R59]

What I find strange about the issue at Rockingham is the Pickups and ASCAR's run at 115dB, They sound louder because the exhaust exit is on the outside (away from the driver). Al's car in comparison was a whisper, even with the Supertrapps taken off.

I would have thought that the whole meeting would be run to the same noise limits, and then those cars running at over 105dB would be advised to get it sorted for the next meeting where the 105dB limit would be enforced.

Wooley, why would I want to hear the commentary, especially if it was Sprozza doing it!

If they employed F1 ITV's James Allen, I'd advocate unsilenced running, then we wouldn't have to hear him talk sphericals.

Rob.

[Al Weyman]

I was advisded that it is because Barretts Homes had taken ownership of the circuit and surrounding land and have applied for 5000 homes to be built and they had there own sound people there waiting for an oppertunity to pounce. There were two bods with recording equipment on turn 4 I noticed, Asian guys and definitely not MSA type people as the were attired in Hi-Vis green vests.

Sadly and unbelieveable I feel something serious is going down there and all that fine and costly infrastructure is going to be torn down to make way for housing, its a sad, sad world at the moment that can allow this to happen if indeed it does but if I was a betting man I will wager with in two years the circuit will be no more.

BTW I was told SCCA were running at 108 db which I got my car tested at prior to fitting SUpertrapps and letting it warm up????

PPS: Wooley I doubt even road cars at full chat would get down to 80db, as Rob as ponted out it is a cubed/squared (not too mathmatically minded sorry) calculation so 80db is way way quieter than 105. I was at a track day when a brand new TVR Cerbra failed a 100db test.

[avro]

For us in the Club racing and National racing arena most have brought older race cars that were designed and built for higher series, for example our Super Tourer was in BTCC where cars were built for a db level greater than 110, and we struggle with noise at most circuits, and advise to add additional boxes is met by gasps from the engine builders as being detrimentale to the car.

When I investigated the situation with the 105db limit in the blue book and the series that run outside of that limit, I was told that if the series you race in show a higher db limit in their regs and this is passed by the MSA then a higher db limit can be run, but how many series ask the drivers what their cars noise levels are when you join ?, and how successful would a club series be if they applied for a db limit of 110db ?

[Al Weyman]

I would say all that is written in the Blue Book would be overwritten at a stroke by the circuit owner. Witness the Historic Lola T70 sent home at Brands at the Sebring meeting, he protested to no avail that the championshiphe run in had no noise restriction but no good, he was still (unfortunately) sent packing. Then the truly ear splitting vintage bikes came on, strange.

[Woolley]

At one unnamed circuit where there was a loudspeaker that broadcast only to the marshals (ie an area where spectators had no access), and where the commentator wasn't exactly a budding Murray Walker - or even James Allen - I can confess that the wires once became parted accidentally...

80db was a wild figure plucked from the air, so meaningless in that sense. The question still reamains, why does it have to be noisy? Hillclimbing went silenced a few years back with absolutely no detriment, and if you have an older car there are no allowances, it has to be silenced. I can see that this could affect power of older cars, but if everyone's required to do the same it should have an equal effect?

[Al Weyman]

I know it is a well talked about topic but the painful annoying noise is in fact the intake roar under load especially with long open trumpets that I see more and more competitors seem to be IMHO foolishly using (one stone in and you have lunched an engine). This noise is not measured and that is what really bugs me, as Rob has said my car was a pussy cat on the track yet I fail a noise test in the pits, how can that be right.

[TheNewBob]

This is a topic I'm certainly interested in knowing more about. Seems like noise is something of a problem within national motorsport at the minute. I quite agree with something Woolley said here:

Originally Posted by Woolley

Since we're wandering around the subject here, I might eventually split this into it's own thread, but I'd like to ask a controversial question: Why does club motorsport have to be noisy?

Good point, I think. I love loud motorsport, but only if the noise is pleasing to the ear (part of the reason I'm such a huge sportscar fan over anything else). I adore a nice-sounding engine, particularly at volume. I think racing at a "grass roots" level doesn't really need the noise that much, though. My nearest circuit is Cadwell - I don't go there as often as I should anymore, but whenever I'm there it's because of the racing, and nothing to do with the noise produced. It's more about people with relatively low budgets having lots of on-track fun in their spare time.

I've become a little concerned recently with the ACO's decision to ponder a noise cap of 113 decibels at Le Mans - but their measuring equipment was to be trackside, I think 15 metres away? I'm not sure what the sound level would be from the exhaust itself if something was producing that sort of noise at a distance of 15 metres.

Yes, I know, that has very little to do with British club racing, but my query is about the decibel scale itself - it's a multiple of something rather than a straight scale, right? I'd very much like to know how that all works.

Interested also how different engine configurations produce different levels of noise. The only instance I can refer to is Team LNT being frustrated last year when their TVR T400R failed a noise test for a British GT round. I was at the Donington round at the beginning of that year and thought that Master Motorsport's Ultima was somewhat louder, but the fuss was around the TVR.

The Tuscan had a screaming straight-6 compared to the Ultima's rumbling Ford V8. I also read on another forum about other lovely deep rumbly engines scoring lower on a sound test than the higher pitched, high revving cars. Therefore, is it sometimes unfair to test differing engines in the same way?

A higher revving/higher pitched engine note has more of a likely ear-splitting nature, whilst a deeper sound seems to rumble the ground a lot more, and create the noise in a different way. Is it likely to be a fault with the system of noise testing, or is it down to the competitor to see that their car meets the requirements, even if they end up having to spend more money on silencing?

[Paul V]

Originally Posted by TheNewBob

Yes, I know, that has very little to do with British club racing, but my query is about the decibel scale itself - it's a multiple of something rather than a straight scale, right? I'd very much like to know how that all works.

As I understand it...
The decibel scale is a measure of difference in pressure - it is not linear. i.e. 90db(A) + 90db(A)=93db(A). So 99db(A) is 8 times louder than 90db(A).
The (A) relates to a weighted scale that approximates to the human ear.
See http://www.phys.unsw.edu.au/~jw/dB.html for a more 'technical' explanation.

Originally Posted by TheNewBob

Interested also how different engine configurations produce different levels of noise. The only instance I can refer to is Team LNT being frustrated last year when their TVR T400R failed a noise test for a British GT round. I was at the Donington round at the beginning of that year and thought that Master Motorsport's Ultima was somewhat louder, but the fuss was around the TVR.

The TVR in question (43) had a different system to the other one (42) which had no problems. I believe it was less restrictive, but generated much more noise. Given the space restrictions of the of a side exit system they have to run, there is a big problem in getting a decently sized 'box' to do the job for long enough.

Originally Posted by TheNewBob

The Tuscan had a screaming straight-6 compared to the Ultima's rumbling Ford V8. I also read on another forum about other lovely deep rumbly engines scoring lower on a sound test than the higher pitched, high revving cars. Therefore, is it sometimes unfair to test differing engines in the same way?

A higher revving/higher pitched engine note has more of a likely ear-splitting nature, whilst a deeper sound seems to rumble the ground a lot more, and create the noise in a different way. Is it likely to be a fault with the system of noise testing, or is it down to the competitor to see that their car meets the requirements, even if they end up having to spend more money on silencing?

The Club Porsche Championships do specify the 2.0m test as they believe it helps with the mechanical noise from their engine/cooling fan etc.
Other than that it would be impractical to do different tests for different engine/layout configurations.

In the end it is down to the teams/owner to comply. The rules have been mainly static for a number of years now so it shouldn't be a suprise to them.
In the case of the LNT cars, a choice was made of power over silencing, that was their problem. The result may have been what broke the camels back, as they had other more mechanical problems with the cars.

HTH