Testing the noise before first track day?

[Maty]

Hi,

I bought a 2005 Mini Cooper S last year to use at weekends and the odd track day. I missed racing (karts and then cars in my teens/early 20's) and I love a bit of supercharger whine so an obvious choice (for me anyway).

After a year of spending and upgrades it's finally ready for its first track day but Im worried about the noise limits. It's got a cat back exhaust on it of unknown make and it is a little noisy, lots of subtle pops and bangs and you can hear it coming. How can I test how loud it is before I book a day at Oulton? I've seen a few apps but not sure how accurate they are and how many revs to hold it at to test.

Or am I worrying for nothing?

[T0MMY]

My car is extremely borderline sound wise and what I've done in the past is actually go along to a track when they've got a trackday on and ask them to test it for me (obviously turn up first thing when they're testing everyone elses cars too). Of course this is only practical if you have somewhere local to go. I did look at apps and things but not sure it's going to replicate what they do on trackdays. Ideally you'd get it tested at the track you're actually booking onto (obviously) so they use the same equipment but even then the noise level is different every time they test mine so it's still a gamble if it's close.

[Bright Halo]

They usually ask you what the max revs are then ask you to hold a 3/4 of that.
Sound gun is usually 1m away at 45 deg down and 45deg away from straight back IIRC?

A portable sound meter off eBay can be bought for about £20

I’ve got one, if you anywhere near Worcester we could have a check?

[E-bmw]

Bright Halo said:

They usually ask you what the max revs are then ask you to hold a 3/4 of that.
Sound gun is usually 1m away at 45 deg down and 45deg away from straight back IIRC?

A portable sound meter off eBay can be bought for about £20

I’ve got one, if you anywhere near Worcester we could have a check?

1/2 metre away, the rest of what you say is correct though.

I also have one need Leeds & they are reasonably accurate from a comparison I did with a few TDOs.

[Maty]

Thanks guys,

I’m in Manchester so Oulton is fairly ‘local’.

I’ll have a look on eBay for a cheap tester and try that first.

It’s not obnoxiously loud.. I’m guessing there will be louder things there but don’t wanna splash out on the 1st track day and get sent home.

[CrutyRammers]

As above, those 10 quid eBay testers are fine, you'll need a freind to help.

[QBee]

I still say that the best test is to take it to the track itself (call them first) and get them to test it for you.
They will be willing - they WANT you on the track. They don't make the noise rules, local councils do, so you and the testers are on the same side.

[brillomaster]

i think you'll be fine... if you think it is 'a little noisy' then you'll be way under. oulton park is 105db static, which is effing LOUD!

an average car is about 75-80db. a sports exhaust might get that up to 85-90db. one of my cars, 3 litre twin turbo with a straight pipe, decats and minimal silencing was 99db. and that was proper antisocially loud.

my guess from what you've said is 84db... let us know what it is if you do get it tested!

[SlowAndDull]

MSV have in the past been happy for me to drop in for a sound check when not booked on a trackday - easiest option and you know you pass or fail the static using their equipment rather than yours..

[Oilchange]

Go to Oulton on a track day and ask them to noise test you.
They should do it for free and you get the result from the horses mouth.

[QBee]

My V8 decatted 5 litre TVR was 105dB on a damp morning. 102 on a warm day.

It is now 91 DB. Changes are a less lairy cam, and a turbo......strangely, a turbo quietens the car. Not strange really - it is in the middle of the exhaust, so muffles it

[untakenname]

The main issue I've found is not the static test but the drive by limits, if you know where the mics are you can ease off as you go past them.
Drive by limits are hard to test for as there's so many environmental variables, weather conditions (dry winter days will register higher) wind direction as well as induction and tyre noise which a static test won't pick up.

[Actus Reus]

Bought myself a sound meter from Amazon for £15 last weekend - pretty sure it's within a couple of db of the 'official' one at Snett - my VX220 Turbo with Larini back box was registering 97 - 98db at 5k rpm and I'm sure I heard the guy at Snett say 95 (at 4500 rpm). About to book a day at Bedford which has a 101 limit, so hoping I'll be clear.

As above the drive by limit worries me a bit so I'll research where the mics are and maybe short shift a little - I was fine at Snett though and by the end of the day was passing the mic at full chat with no worries at all.

[nurseholliday]

brillomaster said:

i think you'll be fine... if you think it is 'a little noisy' then you'll be way under. oulton park is 105db static, which is effing LOUD!

an average car is about 75-80db. a sports exhaust might get that up to 85-90db. one of my cars, 3 litre twin turbo with a straight pipe, decats and minimal silencing was 99db. and that was proper antisocially loud.

my guess from what you've said is 84db... let us know what it is if you do get it tested!

Minis are notoriously bad for noise because the supercharger makes them louder, turbos quieten cars down, it'll definitely be more than 84.

[Rick101]

As said above, it's the drive by that may get you.
It just needs a subtle lift as you pass under the mic and you should be okay.
I really can't imagine anything other than one of those tarted up minis getting anywhere near a static noise limit.

[Actus Reus]

BTW I'm Herts/Essex border if you wanna use my noise meter. They're only £15 but just in case.

[CrutyRammers]

And if you do bust the drive by, they'll bring you in and tell you, so you'll know. You won't get kicked off for the odd transgression, only if you keep wilfully doing it. My first time at Oulton this happened to me, I just shifted up 500 rpm earlier and it was fine - didn't make anything less enjoyable really.

[GiveItSomeWellie]

From memory my R53 with Milltek non-res exhaust was 92db or very close to that.

[QBee]

Actus Reus said:

Bought myself a sound meter from Amazon for £15 last weekend - pretty sure it's within a couple of db of the 'official' one at Snett - my VX220 Turbo with Larini back box was registering 97 - 98db at 5k rpm and I'm sure I heard the guy at Snett say 95 (at 4500 rpm). About to book a day at Bedford which has a 101 limit, so hoping I'll be clear.

As above the drive by limit worries me a bit so I'll research where the mics are and maybe short shift a little - I was fine at Snett though and by the end of the day was passing the mic at full chat with no worries at all.

The Bedford drive by microphones are very very easy to see. And to avoid having a problem too. The only one that ever bothered me was one on a short straight between two quite sharp left handers, quite a long way around the lap, and I simply short shifted past that one to be safe (as i had already been warned after failing the static test that morning).

[Actus Reus]

QBee said:

The Bedford drive by microphones are very very easy to see. And to avoid having a problem too. The only one that ever bothered me was one on a short straight between two quite sharp left handers, quite a long way around the lap, and I simply short shifted past that one to be safe (as i had already been warned after failing the static test that morning).

Cheers - I'll keep an eye on my sighting lap. I may have something fabricated to fit over the pipe to try and knock a few db off too, but that brings heat issues with it...