Bedford noise limits in normal car, decibel reduction kits?

[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

[UTH]

px1980 said:

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 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.

Bedford does seem to be the trickiest track around for this issue.
My brother's Noble M12 has never had a problem, and my Evo never had an issue until my last visit, so it certainly is possible to enjoy a problem-free day, the annoying thing is that it's impossible to know for sure until you get out on track having paid £££ then maybe risk being chucked off. As has been said, there's not much point turning up for a static test to see how you get on as that has little bearing on the drive by results.

[QBee]

It's not the track's fault. it's the local council who are responding to complaints from local residents.
You might be surprised how far noise carries. While I was on a Snetterton track day a few years ago I had to pop into Attleborough for spares. It is 4 miles from the track and I could clearly hear the noise of the track day.

I have now stopped going to Bedford, but mainly because I just don't really enjoy the track.

And Thruxton is far worse on noise, you will find. Most track days have a 90dB static noise limit.

[nickfrog]

The reason why Bedford can be tricky is that it's a very busy track in normal times what with the core business being Corporate work, which is very profitable and easy to control in terms of noise. They have strict noise constraints as part of their consent to operate with the council. The vast majority of unmodified road cars are fine irrespective of temp/wind/pressure/etc and I can see why they won't take a chance to not comply for the sake of a tiny minority of cars in case of adverse acoustic conditions, which some perceive as random when in fact it is a very precise set of limits and tolerances that are finely monitored.

[UTH]

QBee said:

It's not the track's fault. it's the local council who are responding to complaints from local residents.
You might be surprised how far noise carries. While I was on a Snetterton track day a few years ago I had to pop into Attleborough for spares. It is 4 miles from the track and I could clearly hear the noise of the track day.

I have now stopped going to Bedford, but mainly because I just don't really enjoy the track.

And Thruxton is far worse on noise, you will find. Most track days have a 90dB static noise limit.

Agreed, don't blame the track/organisers at all.

The worst are the people who move near a track then campaign against the noise!

[FNG]

px1980 said:

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 production cars will have no issues, bar some loud Ferraris maybe. Clearly that's not true.

My bold. A standard Civic Type R isn't supercharged, this one's an outlier.

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.

[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.

[QBee]

px1980 said:

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.

There's a thread in Reader's Cars about a race Cayman 718 build - the guy doing the work (Steve) will have to comply with racing noise limits, so might know the answers you need

[CrutyRammers]

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)

[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

[nickfrog]

px1980 said:

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

Sounds good indeed, no pun intended. Even at around £150 for the 4.0's bigger two pipes.

[UTH]

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)

Ohhhh this is very interesting. With my bigger silenced decat and one of these you've linked, I imagine I could get back on Bedford in the Evo.

[Mutton]

I use my 997.2 S at Bedford and with the PSE in normal mode I have no issues and don’t have to lift when I pass the noise meters.

[CrutyRammers]

UTH said:

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)

Ohhhh this is very interesting. With my bigger silenced decat and one of these you've linked, I imagine I could get back on Bedford in the Evo.

It's a bit frustrating with all these things, that there's no real way to know, but to buy and try. As it happens, I've only needed them once so far, at croft (when, it turned out, all of the wadding had melted and blown out of my straight-through exhausts, so it was REALLY LOUD!), and they did the job, with no real noticable downside. Still, it cost £120 quid to find out, which isn't nothing.
Previously I'd used some of the more restrictive types, at Oulton, and they not only didn't reduce the sound nearly as much (I had to short shift all day), they noticeably choked the engine a bit. I tried various other things, like pointing the outlet at the ground (which made it worse in my case), and putting big round plates about 1" from the outlet, which made it better head on, but perhaps a bit worse at 45 degrees.
Some of the tests here -> http://alfadax.com/content/after/2016/croft.htm

[CrutyRammers]

px1980 said:

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

Yeah it's quick, just a single clamp. Though I had to modify mine as I've got a very curved outlet.

[UTH]

CrutyRammers said:

UTH said:

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)

Ohhhh this is very interesting. With my bigger silenced decat and one of these you've linked, I imagine I could get back on Bedford in the Evo.

It's a bit frustrating with all these things, that there's no real way to know, but to buy and try. As it happens, I've only needed them once so far, at croft (when, it turned out, all of the wadding had melted and blown out of my straight-through exhausts, so it was REALLY LOUD!), and they did the job, with no real noticable downside. Still, it cost £120 quid to find out, which isn't nothing.
Previously I'd used some of the more restrictive types, at Oulton, and they not only didn't reduce the sound nearly as much (I had to short shift all day), they noticeably choked the engine a bit. I tried various other things, like pointing the outlet at the ground (which made it worse in my case), and putting big round plates about 1" from the outlet, which made it better head on, but perhaps a bit worse at 45 degrees.
Some of the tests here -> http://alfadax.com/content/after/2016/croft.htm

I was going to ask about the restriction of air flow side of things.....I've never wanted to use a bung for fear of causing the car problems (I've had enough issues with the car running as it should LOL), so does this device not restrict things as much in that sense?

[CrutyRammers]

UTH said:

I was going to ask about the restriction of air flow side of things.....I've never wanted to use a bung for fear of causing the car problems (I've had enough issues with the car running as it should LOL), so does this device not restrict things as much in that sense?

I've no actual figures or anything. Presumably they must restrict a bit, though not as much as a bung would. I certainly noticed the bung types (it felt "held back", and got hotter IIRC), I didn't really notice these. It was a few years back and only the once though.

[UTH]

CrutyRammers said:

UTH said:

I was going to ask about the restriction of air flow side of things.....I've never wanted to use a bung for fear of causing the car problems (I've had enough issues with the car running as it should LOL), so does this device not restrict things as much in that sense?

I've no actual figures or anything. Presumably they must restrict a bit, though not as much as a bung would. I certainly noticed the bung types (it felt "held back", and got hotter IIRC), I didn't really notice these. It was a few years back and only the once though.

Thanks good to know, it's certainly worth having one in the boot and trying Bedford again so I have options if I do get flagged. Better than a totally wasted track day.

[Dan_The_Man]

FNG said:

My bold. A standard Civic Type R isn't supercharged, this one's an outlier.

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.

Yes sorry definitely an outlier, we use this bung for Bedford:


Bedford cup useful for purging the water/methanol injection, custom "quiet" airbox on the right.

[braddo]

px1980 said:

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.

Just go and ask on the Porsche forum if anyone has taken a 4L GTS on track and how loud is it. A factory 'sports exhaust' with valves open might be noisy so it's worth asking owners.

At least one advantage is that mid-engined (and rear) cars have way less induction noise when approaching a sound meter compared to modified front engined cars. I remember a couple of very loud supercharged Civics and a 306 GTI on throttle bodies at Snetterton once, and they are MUCH louder coming towards you than a GT3, even though the latter hits 103-105db on the static test.