noise tests at track days

[gee46]

Track Day Noise Limit Guide
A look at the noise test and circuit noise limits

Track Day Noise Testing

Track day noise limits and noise testing have been a subject of much discussion in more recent times. With the increased pressure that councils are putting on circuits to keep the noise level down, the circuits are not only having to be very strict with enforcing the rules and who they let on the track, but they are also having to lower the maximum decibel limits previously set and agreed upon.

This indicates two things; the first is that at some circuits it is becoming more difficult to actually pass the noise test (for those with systems on the louder side that is) but it also indicates something more significant than that.

Councils are cracking down on noise levels, and the more we break those rules the more pressure the circuits are going to be put under, to the point where circuits will have no choice but to set ultra low decibel limits, or worse stop track days all together.

You only have to read the Croft story about why there’s next to no track days there anymore to know this is a clear and present issue.

So what’s the state of play now? In April 2012 the below guidelines were issued out to show both track day organisers and riders the current noise limits and how each type of machine is tested.

Circuit limits:

Anglesey – 105db (ACU static test)

Bedford – 101db (ACU static test) and 87.5db drive by. All drive-bys meters are at 20 metres from the edge of the track.

Brands Hatch Indy – 105db (ACU static test) and 92db drive by.

Brands Hatch Indy Evenings – 102db (ACU static test) and 92db drive by.

Brands Hatch GP – 101db (ACU static test) and 92db drive by.

Cadwell Park – 105db (ACU static test) and 92db drive-by.

Donington Park – 98db and 105 db measured as a drive by with multiple meters at trackside.

Mallory Park – 105db (ACU static test) during the weekdays and Tuesday to Friday. Saturdays and Sundays are 98db (ACU static test) for Trackdays.

Oulton Park – 102db (ACU static test) and 89db drive by.

Pembury – 102db (ACU static test).

Silverstone – 102db drive by meters at circuit (customers are photographed on the national straight as they trigger the meter ) but 105db measures at ¾ revs are used on the static test when required.

Snetterton – 102db (ACU static test) and 92db drive by.

The majority of circuits use the ACU guidelines for their static test. Here is how the test is performed and what is required:

Each bike is measured 0.5 meters away from the exhaust at an angle of 45 degrees while the engine is being held at the following RPM:

Engine Size 1 cylinder 2 cylinder 3 cylinder 4 cylinder
250cc (4 stroke) 5,500rpm 8,500rpm
400cc (4 stroke) 5,000rpm 6,500rpm 7,000rpm 8,000rpm
600cc (4 stroke) 5,000rpm 5,500rpm 6,500rpm 7,000rpm
750cc (4 stroke) 5,000rpm 5,500rpm 6,500rpm 7,000rpm
+750cc (4 stroke) 4,500rpm 5,000rpm 5,000rpm 5,500rpm
125cc (2 stroke) 7,000rpm
250cc (2 stroke) 7,000rpm
500cc (2 stroke) 5,500rpm 7,000rpm 7,000rpm


If the motorcycle has two separated exhausts the measurement will be taken as above from the midpoint between the two.

As you can see the vast majority of the circuits use the ACU guidelines when performing a static test, but even so not every test is the same and it is something that is quite frustrating to riders that can pass at one circuit but not the other, but unfortunately this has been an issue for quite some time and it doesn’t look like it’s going to get resolved any time soon, which means we just have to get by as best we can.

So that’s the circuit requirements and how the tests are taken. Here are a couple of points to not only help you get through noise testing, but also ensure that the circuits (and ultimately local councils) are kept happy with the noise levels.

Warm up you engine

If you warm your engine before you get noise tested, generally this will reduce the noise level of your bike to a degree, so if you’re worried it might be close to the limit, warm your engine before getting tested.

Some say this doesn’t have a massive benefit and I guess different bikes and exhaust systems will be different, but I know from one personal experience that by warming my bike before getting tested I went from being over the limit, to passing with flying colours.

Fit a baffle

If you have one, fit it. Circuits are becoming increasingly demanding when it comes to baffles and some even say have your baffle fitted regardless of what your noise level reads without it.

If you don’t have a baffle and you’re concerned about being over, then buy one. They’re not expensive and they could well save you from packing your bags early and going home.

Different baffles will have a different effectiveness, but you can expect a baffle to change the noise level of your exhaust from anything from 2 to 8 decibels.

Don’t worry about any performance drop either. It could well drop the performance of a higher capacity bike by 5 or so bhp, but that more than likely equates to less than a second in terms of lap times anyway (obviously this is a guesstimate). It just isn’t worth it at the risk of getting sent home.

Don’t try to fool the testers!

This is a biggy for me. I hear of people claiming they have a bigger bike than they do so they test at a lower rpm, or they get tested on a quieter bike and swap stickers over, or simply take their baffle out after they have been tested, all in an attempt to get through noise testing and get out on track.

What a lot of people fail to realise though is that not only will they more than likely get pulled up by the drive by meters later anyway, they are also contributing to the problems surrounding circuit noise and in turn only serving to hurt themselves in the long run.

Councils won’t stand for the circuits not adhering to the noise restrictions (of which they have solid ways to monitor) and as a result will put more and more pressure on them to lower the limit or stop it all together. By sticking to the rules we all stand the best chance of having track days here for years to come.

So please, don’t bluff your way though noise testing. If your bike is over, get it lowered and keep it there. By doing this you’re helping yourself and every other track day rider.

Don’t lose your rag if you get turned away

If the tester turns you away for being over the limit, he’s just doing his job. Don’t go throwing your toys out the pram as this won’t help anyone. Ask them what you can do to make it through the test and they or someone else in the vicinity will more than likely be able to help, but they aren’t likely to do that if you start throwing abuse or sly comments their way.

Hopefully the above has helped answer any questions about noise testing and the circuit limits. Use the advice here to not only help you best prepare for your next noise test, but also ensure that we as track day riders help keep the circuits out of trouble so they can continue to provide us with this fantastic service.

[layne]

You didn't mention the rules for rain, wind and temperature and rounding down. And Combe which has its own rev range for the test.

[scorcher]

Track Day Noise Testing


Hopefully the above has helped answer any questions about noise testing and the circuit limits..

Nope , heres another...............

How do they test if you haven't got a rev counter? (my current KTM 950 SM wasn't produced with a rev counter)

[gee46]

I do not know the rules for combe was just doing the ones that some off us have booked for nexted year and trying to help answer some people worries and if u know it for combe please add it on

[billinom8s]

or just pack your standard can or a dB killer

[Tractorwackyracer]

if you have a six tell them its a 1000 and rev it less !!!! a bit naughty but it gets you on track

[layne]

Done that one but won't work at Combe as they ask everyone to rev to 3/4 of max revs. Moving the needle or scale round 1500rpm does though

Regards no rev counter, Cadwell where quite accommodating and held the throttle open at what sounded like 5500. Also tested my dB meter for me with there master clicker.

However had an argument with the lad at Pembrey before he would accept it even when it was well within.

Some tracks (Assen & Magny Cours) have a rev counter that clip onto a HT lead to help with older race bikes.

[Bullet]

I'm lucky as I can change my rev counter on my dash if I'm that way inclined! I can show it at 6000 rpm when in fact it's only doing 4000rpm ! Beauty of technology
But I'm honest so put a feckin baffle in instead ;)

[layne]

One spark plug cap off works too at Paul Ricard and Spa ;)

[Ruffian]

Bugger well mine at 7000rpm Is 108db, so may need a bit of dulling down, admittedly that is cold but with baffle in so who knows, I feel a bit of fabrication coming on!!! Lol

[layne]

A perforated Coke can in the collector works well at Suzuka.

Strangely the factory RC45’s had exactly the same ring to them at noise testing!!!

[Red5]

Has anyone any experience with using db apps on your phones?? Just wondering if any are renowned for being accurate or less so than others. I have down loaded one to give me half a clue but if it's 10% out for example, I could be another 8,9 or 10 Db out...

We all like to think we can pull one over but really, I agree with Gee there, if we all just play the game with the riles, then we have a leg to stand on when the powers that be start really killing our track days off.

[layne]

I have a meter if you want to test you bike and the App.

[dukes22]

The problem with the phone app meters Is that some phone microphones will only work upto about 85db . When I used one i couldn't understand how my old ducati was so quiet. It wasn't.
it was the phone.