Bedford noise limits in normal car, decibel reduction kits?

[px1980]

I'm debating buying a Cayman with a view to use it regularly on track (but also on road/as daily), either 718 GTS 4.0 or 981S.

Bedford is the venue that works best for me (by far the nearest & I'm new to TDs so big run off is a massive plus). I'm a little concerned having read about people getting black-flagged in their normal road cars due to drive-by noise limit violations. I called MSVT and they said factory Cayman "should be absolutely fine", but then people's reports on here suggest otherwise.

I'd like to avoid a situation in which I spent tens of thousands on a second car, then find out I can't use it at my preferred track.

In case it does happen to me, what are people's views on decibel reduction kits such as https://www.demon-tweeks.com/uk/decibel-slayer-bol... ? Basically, can I assume that in worst cay scenario on the day, I'd just slap this thing onto the exhaust and that'd be a sure-fire way of ensuring I can carry on with my trackday?

Or maybe this is a non-issue, and in a car such as Cayman, I'll have no issues if sports exhaust is kept off? I find it a little hard to believe that a factory 2020 car (say the 718 GTS) might be in breach of noise limits, but there you have it...

[px1980]

TTmonkey said:

Go to a track day as an observer. Observe other cars. See which breaks the limits.

Act on your findings.


I’ve only seen these devices on TVRs on track days, but that was years ago.

Well I have been, I've definitely seen Nissan GT-Rs, AMG GT, 911s, Lotus Exige's. So plenty of cars which I'd assume (?) would be in the same noise bracket as a Boxster GTS. But whether you get black flagged or not at Bedford seems a little random...

[px1980]

TTmonkey said:

Last time I went two GT3 RS’s were kicked out of the event because of noise and because they were there to race each other. They were told to stay apart but they were there to be together, and both going through the noise checks together, right pair of asholes.

I’ve never seen a booster/cayman black flagged.

haha this is hillarious;) And thanks for clarifying re. boxster/cayman. You'd expect there to be a biiiig difference in noise levels between GT3 RS and non-GT Cayman (including 4.0 GTS, I'd hope)

[px1980]

UTH said:

I hear you here!! My Corvette is (beautifully) loud....I knew this going in, but I thought 'loud' days with 105 static, 101 drive by I'd be ok, but turns out I'm a little too loud even for the 101db drive by! So I won't ever be able to truly floor it around a track in the UK in it. Not the end of the world as I didn't buy it as a track car only, but it would have been nice to go to a few without worrying.

What a shame. I did actually briefly think of getting the new 2020 UK-spec Corvette (C8) which seems rather good value-for-money, but I quickly realised it wouldn't be an option for track (due to noise & also weight)

[px1980]

NardoRS said:

You should be fine in your Cayman at Bedford. I’ve been there 3 times in my Audi TTRS and, even though I was well under the static, I did trip one of the track side meters. It was always the same one and I finally figured out it was a gear change happening in line with the mic; I had to short shift at that point and had no more problems.
I did test the static with exhaust valves open and was just under the limit.
I think you’ll be ok and my experience each time was the circuit staff want to help you comply.

thanks. The TTRS is quite a noisy car in general, right? I've never driven or probably even heard one, but reviews mention "sonorous";) So if you're "well under" on the static test, I hope that the Cayman will be, too (it'll be the 6-cylinder 4.0 without turbo though)

Edited by px1980 on Wednesday 6th January 09:40

[px1980]

UTH said:

My only word of caution is that just because you may come in below the static, it seems you could still be caught out on the drive by like I have been.
Short shifting etc can be done when passing the mics, just bear in mind the static test isn't a perfect indicator of being fine out on track.

Thanks, and agreed, it does seem that 90% of people who report problems at Bedford are caught out on the drive-by, not static.

Hence me asking in the original post about those exhaust decibel reduction kits - i.e. can I assume that should I be unlucky (because it does seem to come down to luck) on the drive-by, there is "something" that I could buy, have in the boot of the car at all times and just slap/screw on the exhaust after say the second black flag, when I'm running a real risk of being thrown out.

[px1980]

Dan_The_Man said:

Been black flagged there several times and it's always on the drive by, car is a Honda Civic Type R. It was very strange as we run with an extra exhaust box sticking out of the car and it turned out the supercharger induction noise was triggering it so a new re-designed baffled intake has meant more Bedford track time.

thanks. I've seen Civics Type R and they didn't strike me as particularly loud? There is an article on evo.co.uk about track noise limits, and a Bedford representative says virtually all production cars will have no issues, bar some loud Ferraris maybe. Clearly that's not true.

If regular Porsches (and not just GT3 RS - on another thread GTS 4.0 was mentioned), hot hatches and other production cars are above noise limits, then clearly there isn't a non-electric car that you can actually enjoy AND be certain you'll be below limit at all times. Shame. But at least now I know that this shouldn't be a factor in my purchase. I was thinking if I should get the Boxster S, not GTS, but from what I read this wouldn't be any more of a "guarantee" that it'll stay below limit.

Edited by px1980 on Thursday 7th January 12:41

[px1980]

FNG said:

The Bedford noise limit is low and tricky for modified stuff to pass, but any modern production car aside from something especially fruity like a GT3 or low volume (sub-5000 units p/a I believe) like Ferraris etc should pass. Certainly a Boxster S shouldn't give you any problem, it's a production road car and won't have any exemption from passing volume production noise limits.

To be clear, I'm considering a 4.0 litre 6-cylinder Cayman GTS, not the 2.5L 4-cylinder S model. But still, GTS is a 2020 model, so presumably (?) compliant with all kinds of latest EU noise regulations.
I wish there were some kind of manufacturer-published tables of exhaust noise levels, but I searched a lot and couldn't find any.

[px1980]

CrutyRammers said:

I've tried all manner of these and done loads of testing, I've tried homemade things, cheap things, expensive things. The one linked in the OP are pretty bad. The absolute best I've found have been the decibel devil, which are (surprise surprise) the most expensive. https://www.advantage-motorsport.co.uk/decibel-dev.... These gave me a consistent 3dB reduction on my Dax.
(Depending on space, you may have other options such as full add-on silencers, I'm rather limited so I can only use the small insert type things)

great shout, £63 is still very much acceptable, and from the picture it looks like installation will take a minute or two

[px1980]

hodgre said:

I have a 718 boxster s and on first trip to bedford was blackflagged for drive by noise and this was tootling around the hairpins in the pouring rain. However, no problems when sport exhaust switched off for the rest of the day and on subsequent visits.

It does seem to be the case that boxters get blackflagged with sports exhaust on, based on what I’ve read. Less so, I hope, with it off

[px1980]

Hi, I thought I’d update about my own experience since I picked up the 718 Cayman GTS 4.0 in April and used in on track several times (Brands, Bedford, Silverstone).

In short – I’ve had no issues at Bedford on the 2 track days I’ve done. The static reading was 99dB once and 92dB on another day, the former obviously quite close to the limit (=102) but I didn’t have issues on drive-by.
At first, I was short-shifting near the noise meters and always keeping the sports exhaust off. Towards the end of the day I tried staying in lower gear (2nd before the hairpin) and keeping the sports exhaust on – and again, I had no issues.

I know however that 981 GT4 is much noisier and recently I was chatting with an owner of one who was having to use some kind of silencer system to keep it under noise limit. But stock 718 4.0 had no issues.

[px1980]

MadCaptainJack said:

I’m guessing that you don’t get the track day fee refunded if you’re kicked out for exceeding the noise limits?

I don't know I'm afraid. What I do know is that the staff at Bedford try to make it fair. So if you’re on or near the limit during static testing, they’ll tell you about it and advise what can be done (point out the parts of circuit where you should consider short-shifting etc). And then it’s not as if first time you’re above limit on drive-by you’re kicked out; there’s a noise board first, you have a chat, then first black flag, and it’s only after the second black flag that your day is finished.

And BTW I do see GT4s, GT3s, McLarens and even Ferraris occasionally at Bedford, and it’s meant to be the track with lowest limits of all major tracks.