Loud cars and track days

[Jasmine1]

I've just bought a 991.1, the previous owner had the original exhaust modified by removing/altering some of the baffles.

The car sounds great, and I want to take it on track, but I'm concerned it may be too loud for the sound limits. I've got no way to say for sure, it's just a hunch I get, so I don't want to risk spending hundreds of pounds on a track day and incidentals only to fail the sound test or be removed from track.

Is there any way I can get my car reliably tested to see how loud it is? And if it is too loud, what are my options? I know I could pick up a cheap standard exhaust off eBay but I'd rather avoid this. Can you get mufflers that bolt onto the exhaust tailpipes to quieten it down?

Edit to add, I've also looked at "unsilenced days" but it seems only Donnington Park does these, at tremendous cost. Are people really paying £995 to do a track day?!

Edited by Jasmine1 on Tuesday 26th July 19:41

[dhdev]

Just go along to any local trackday and ask them to sound test your car, I'm sure they'd be happy to do it

[brillomaster]

Indeed, bedford do sound testing before you even get to the sign on. Just turn up about 8am on the day of a trackday, get a sound test, then crack on with the rest of your day.

[Jasmine1]

That's a good idea, but I've been to a couple of days where they don't do a static noise test, instead, they just chuck you off if you ping one of the noise meters.

I guess I'd have to find a track day that does static noise testing, that isn't a million miles away.

[phazed]

What’s your local track?

[Jasmine1]

Oulton Park is about an hour away.

[samjlevy]

Jasmine1 said:

I've just bought a 991.1, the previous owner had the original exhaust modified by removing/altering some of the baffles.

The car sounds great, and I want to take it on track, but I'm concerned it may be too loud for the sound limits. I've got no way to say for sure, it's just a hunch I get, so I don't want to risk spending hundreds of pounds on a track day and incidentals only to fail the sound test or be removed from track.

Is there any way I can get my car reliably tested to see how loud it is? And if it is too loud, what are my options? I know I could pick up a cheap standard exhaust off eBay but I'd rather avoid this. Can you get mufflers that bolt onto the exhaust tailpipes to quieten it down?

Edit to add, I've also looked at "unsilenced days" but it seems only Donnington Park does these, at tremendous cost. Are people really paying £995 to do a track day?!

Edited by Jasmine1 on Tuesday 26th July 19:41

I got some bolt on silenced tips for my old GT3RS, they just bolted on in place of the original exhaust tips and pointed down, think it cost about £200 from a local exhaust place (JP Exhausts).

Never actually needed to use them but good to have.

[phazed]

Out of interest, readings taken on 3 track days, all very similar on my 987.1 S.

Standard exhaust 90db
Sport mode, (flaps open) 92db.

Point is it sounded far louder in sport but was only 2db higher.

Worth getting yours checked as it may not be so bad.

[BertBert]

If it's a trek to get it tested at a track, you could get an idea by buying a cheap sound pressure meter from Amazon. There's a risk it won't be accurate enough, but I would think it'll give you a good idea. Or even start with a phone app sound meter.

You'll need a friend to help with either the revs or the meter #obs.

[Kswap]

Oulton Park do static noise tests before Trackdays if that’s your closest one.

[carl_w]

If you get a noise meter, the process for MSUK-regulated motorsport (and I presume it's the same for trackdays) is to measure 1m from the exhaust at a 45° angle. Our friendly environmental scrutineer has a 1m long thin metal rod with a 45° bend at the end attached to his noise meter to make it easier.

Regardless of accuracy (which should be in the specs of the meter) if you're well under the limit you should be good to go. Remember that 3dB is a doubling of sound pressure level.

[NoBrakesWC]

Get one of those downpipes that shoots the sound down makes it better. Sound guys are usually nice and won't have it right against it. Jut rev up to a bit lower than they ask for as well

[carl_w]

NoBrakesWC said:

Get one of those downpipes that shoots the sound down makes it better. Sound guys are usually nice and won't have it right against it. Jut rev up to a bit lower than they ask for as well

Good point, when they ask you what your maximum rpm is don't do as I did once and say 8,000.

[phazed]

It nearly always is , 4,500-4,750 .

[UTH]

Jasmine1 said:

I've just bought a 991.1, the previous owner had the original exhaust modified by removing/altering some of the baffles.

The car sounds great, and I want to take it on track, but I'm concerned it may be too loud for the sound limits. I've got no way to say for sure, it's just a hunch I get, so I don't want to risk spending hundreds of pounds on a track day and incidentals only to fail the sound test or be removed from track.

Is there any way I can get my car reliably tested to see how loud it is? And if it is too loud, what are my options? I know I could pick up a cheap standard exhaust off eBay but I'd rather avoid this. Can you get mufflers that bolt onto the exhaust tailpipes to quieten it down?

Edit to add, I've also looked at "unsilenced days" but it seems only Donnington Park does these, at tremendous cost. Are people really paying £995 to do a track day?!

Edited by Jasmine1 on Tuesday 26th July 19:41

I feel your pain, my C7 Corvette breaks the drive-by limit at Goodwood (101db driveby) if I'm going full throttle past the mics.
I have looked into what trackday might be ok for my car, and only found exactly the same as you, very expensive day at Donnington.

Sadly I think I'm going to accept that my Corvette won't be for UK tracks, and maybe need to play some trips into Europe to enjoy it.

[phazed]

Bolt on cans?

I used them for nearly every track day on my 5.5 TVR.

[UTH]

phazed said:

Bolt on cans?

I used them for nearly every track day on my 5.5 TVR.

Not sure they'd fit very easily to my exhausts, the Americans didn't design them with silencing in mind

[phazed]

Ah……..

Buy a Porsche?

[brillomaster]

not really sure the suggestions to lie about your red line, or under rev it during the static test are particularly helpful - you'll either get black flagged and kicked off the day while you're lapping, or you'll just have to lift and coast past the microphones, which isnt that fun.

personally, if you have a car that is too loud for the trackday, either sort your silencing out, or go on a day with louder limits. Trackdays are fragile things, if people try and drive over the noise limits, the council will shut them down and then nobody gets to go. if you're building a car specifically to do trackdays, then it would be wise to make it quiet so you can still go on the tracks with low limits, like goodwood.

[UTH]

brillomaster said:

not really sure the suggestions to lie about your red line, or under rev it during the static test are particularly helpful - you'll either get black flagged and kicked off the day while you're lapping, or you'll just have to lift and coast past the microphones, which isnt that fun.

personally, if you have a car that is too loud for the trackday, either sort your silencing out, or go on a day with louder limits. Trackdays are fragile things, if people try and drive over the noise limits, the council will shut them down and then nobody gets to go. if you're building a car specifically to do trackdays, then it would be wise to make it quiet so you can still go on the tracks with low limits, like goodwood.

Agreed on your points except the point about Goodwood. 105 static and 101 driveby is one of the highest limits around.