Noise levels from a Chim exhaust
Discussion
Hi All!
Does anybody know roughly how much noise a 400 chim puts out at the pipes with precats removed at ~4000rpm?
I'm prepping my car to go out on a couple of track days next year, specifically Castle Coombe and I'm slightly concerned she'll fail the noise test as we all know these cars are loud and proud even in standard spec!
Has anybody been to a track day at CC in a Chim and had any issues?
Cheers n beers
Does anybody know roughly how much noise a 400 chim puts out at the pipes with precats removed at ~4000rpm?
I'm prepping my car to go out on a couple of track days next year, specifically Castle Coombe and I'm slightly concerned she'll fail the noise test as we all know these cars are loud and proud even in standard spec!
Has anybody been to a track day at CC in a Chim and had any issues?
Cheers n beers
QBee? Where are you?Chimaera27 said:
Hi All!
Does anybody know roughly how much noise a 400 chim puts out at the pipes with precats removed at ~4000rpm?
I'm prepping my car to go out on a couple of track days next year, specifically Castle Coombe and I'm slightly concerned she'll fail the noise test as we all know these cars are loud and proud even in standard spec!
Has anybody been to a track day at CC in a Chim and had any issues?
Cheers n beers
Standard exhaust with pre cats in place is about 94 decibels Does anybody know roughly how much noise a 400 chim puts out at the pipes with precats removed at ~4000rpm?
I'm prepping my car to go out on a couple of track days next year, specifically Castle Coombe and I'm slightly concerned she'll fail the noise test as we all know these cars are loud and proud even in standard spec!
Has anybody been to a track day at CC in a Chim and had any issues?
Cheers n beers
97 pre cats removed
105 pre cats and sleeved exhaust.
All taken at 4000revs at various race circuits around the Uk.
My cars a 450 but shouldn't be much different.
My supercharged 450 with no cats and standard main exhaust (Clive Ford stainless manifolds & Y piece) regularly measures between 99 & 101 dbA static @ 4000 rpm with no additional silencers. I have only had a problem once, at Bedford Autodrome even with trackday silencers fitted and still got kicked off supposedly measuring 102 dbA on drive by!!! 
having measured 99 dbA static @ 4000 rpm with extra silencers and 105 dbA without.
My advice is to call the particular circuit beforehand and check their criteria and method of measurement, they should all be the same but my experience suggests otherwise. If the circuit is local it would be a good idea to ask them if you could turn up beforehand and get checked.
having measured 99 dbA static @ 4000 rpm with extra silencers and 105 dbA without.My advice is to call the particular circuit beforehand and check their criteria and method of measurement, they should all be the same but my experience suggests otherwise. If the circuit is local it would be a good idea to ask them if you could turn up beforehand and get checked.
That extra 500 rpm does make quite a difference.
Precats removed, main cat in, standard exhaust should be quite quiet.....by Chimaera standards.
My 5 litre, with the main cat removed, was regularly between 99 and 108 db. But occasionally as low as 97.
Trouble is the noise tests themselves vary, meters vary. and noise levels are always worse on cold damp foggy mornings, and with a building close at hand, so a March track day will give you more problems than a July one, and as far as I remember, Castle Combe do the test close to buildings.
The advice above, to go get the car tested at the track before you book is good. At least you will know where you stand.
I do have a spare pair of bolt on cans you can borrow for safety, just let me know. They will soften the sound as well as knocking about 4-5 db off, and also it helps to make the track officials believe that you are trying to comply. I had to use mine at Castle Combe.
Do remember that the track guys are all petrol heads themselves, and wouldn't dream of applying noise limits. It's the local councils who are monitoring the noise levels and applying limits. For example, Bedford's drive by noise meters are set to 87.5 dB (but are 10 metres from your car) and are connected direct to the council offices.
Can I just say that I don't know your track driving experience, but Castle Combe wouldn't be my first choice of beginner's track - It's basically a bumpy high speed track consisting of four corners, two chicanes and straights. The four corners have armco barriers literally 5 metres off the track - no room for error. The first time I drove it I was definitely shocked at the lack of run-off, and it took me until the afternoon to get up to speed - and it was my 25th track day at a variety of tracks. I survived.
On my subsequent outings, at Mallory Park and Hullavington, I left the track on both days at over 100 mph (brain failure at Mallory, brake failure at Hullavington) and was extremely grateful for the space available.
Precats removed, main cat in, standard exhaust should be quite quiet.....by Chimaera standards.
My 5 litre, with the main cat removed, was regularly between 99 and 108 db. But occasionally as low as 97.
Trouble is the noise tests themselves vary, meters vary. and noise levels are always worse on cold damp foggy mornings, and with a building close at hand, so a March track day will give you more problems than a July one, and as far as I remember, Castle Combe do the test close to buildings.
The advice above, to go get the car tested at the track before you book is good. At least you will know where you stand.
I do have a spare pair of bolt on cans you can borrow for safety, just let me know. They will soften the sound as well as knocking about 4-5 db off, and also it helps to make the track officials believe that you are trying to comply. I had to use mine at Castle Combe.
Do remember that the track guys are all petrol heads themselves, and wouldn't dream of applying noise limits. It's the local councils who are monitoring the noise levels and applying limits. For example, Bedford's drive by noise meters are set to 87.5 dB (but are 10 metres from your car) and are connected direct to the council offices.
Can I just say that I don't know your track driving experience, but Castle Combe wouldn't be my first choice of beginner's track - It's basically a bumpy high speed track consisting of four corners, two chicanes and straights. The four corners have armco barriers literally 5 metres off the track - no room for error. The first time I drove it I was definitely shocked at the lack of run-off, and it took me until the afternoon to get up to speed - and it was my 25th track day at a variety of tracks. I survived.
On my subsequent outings, at Mallory Park and Hullavington, I left the track on both days at over 100 mph (brain failure at Mallory, brake failure at Hullavington) and was extremely grateful for the space available.
ClassiChimi said:
Chimaera27 said:
Hi All!
Does anybody know roughly how much noise a 400 chim puts out at the pipes with precats removed at ~4000rpm?
I'm prepping my car to go out on a couple of track days next year, specifically Castle Coombe and I'm slightly concerned she'll fail the noise test as we all know these cars are loud and proud even in standard spec!
Has anybody been to a track day at CC in a Chim and had any issues?
Cheers n beers
Standard exhaust with pre cats in place is about 94 decibels Does anybody know roughly how much noise a 400 chim puts out at the pipes with precats removed at ~4000rpm?
I'm prepping my car to go out on a couple of track days next year, specifically Castle Coombe and I'm slightly concerned she'll fail the noise test as we all know these cars are loud and proud even in standard spec!
Has anybody been to a track day at CC in a Chim and had any issues?
Cheers n beers
97 pre cats removed
105 pre cats and sleeved exhaust.
All taken at 4000revs at various race circuits around the Uk.
My cars a 450 but shouldn't be much different.
My standard 450 measured 92dB at 2/3 max revs.. I was a bit embarrassed TBH!
Nick
BmthRob said:
I did Castle Combe last year, 400, precats out, main cat in, standard box. I asked the guy what the reading was, he said 88!
Same setup at Abingdon was 95dB.
As mentioned above, testing equipment and conditions vary but I don't think you'll have a problem at Combe.
No pre-cats and sleeved came out at 115db at Combe for me.Same setup at Abingdon was 95dB.
As mentioned above, testing equipment and conditions vary but I don't think you'll have a problem at Combe.
As TV8 said above, pop along to your local track during a trackday and they will happily measure your car. You don't have to be on the trackday. They are run regularly - not always by the track owners so call the track and ask.
That said, the same car can read differently depending on a lot of factors so a 100dB reading on August 1st could be 102dB on December 1st. The idea of the above is to see if you need to do anything about it.
If the car reads borderline, then look at getting (buy or borrow) some trackday cans. There are loads to choose from and don't need to be pretty just secure.
Are you going to do a lot of trackdays?
That said, the same car can read differently depending on a lot of factors so a 100dB reading on August 1st could be 102dB on December 1st. The idea of the above is to see if you need to do anything about it.
If the car reads borderline, then look at getting (buy or borrow) some trackday cans. There are loads to choose from and don't need to be pretty just secure.
Are you going to do a lot of trackdays?
QBee said:
That extra 500 rpm does make quite a difference.
Precats removed, main cat in, standard exhaust should be quite quiet.....by Chimaera standards.
My 5 litre, with the main cat removed, was regularly between 99 and 108 db. But occasionally as low as 97.
Trouble is the noise tests themselves vary, meters vary. and noise levels are always worse on cold damp foggy mornings, and with a building close at hand, so a March track day will give you more problems than a July one, and as far as I remember, Castle Combe do the test close to buildings.
The advice above, to go get the car tested at the track before you book is good. At least you will know where you stand.
I do have a spare pair of bolt on cans you can borrow for safety, just let me know. They will soften the sound as well as knocking about 4-5 db off, and also it helps to make the track officials believe that you are trying to comply. I had to use mine at Castle Combe.
Do remember that the track guys are all petrol heads themselves, and wouldn't dream of applying noise limits. It's the local councils who are monitoring the noise levels and applying limits. For example, Bedford's drive by noise meters are set to 87.5 dB (but are 10 metres from your car) and are connected direct to the council offices.
Can I just say that I don't know your track driving experience, but Castle Combe wouldn't be my first choice of beginner's track - It's basically a bumpy high speed track consisting of four corners, two chicanes and straights. The four corners have armco barriers literally 5 metres off the track - no room for error. The first time I drove it I was definitely shocked at the lack of run-off, and it took me until the afternoon to get up to speed - and it was my 25th track day at a variety of tracks. I survived.
On my subsequent outings, at Mallory Park and Hullavington, I left the track on both days at over 100 mph (brain failure at Mallory, brake failure at Hullavington) and was extremely grateful for the space available.
Thanks for the heads up, I have watched the video on the website and it does look fast. I have no track day experience to speak of, but I used to race karts competitively and I've raced Formula Mazda so now how to drive fast, but it is a new circuit to me so I'll bear what you say in mind. I didn't know Hullavington had track events, they any good?Precats removed, main cat in, standard exhaust should be quite quiet.....by Chimaera standards.
My 5 litre, with the main cat removed, was regularly between 99 and 108 db. But occasionally as low as 97.
Trouble is the noise tests themselves vary, meters vary. and noise levels are always worse on cold damp foggy mornings, and with a building close at hand, so a March track day will give you more problems than a July one, and as far as I remember, Castle Combe do the test close to buildings.
The advice above, to go get the car tested at the track before you book is good. At least you will know where you stand.
I do have a spare pair of bolt on cans you can borrow for safety, just let me know. They will soften the sound as well as knocking about 4-5 db off, and also it helps to make the track officials believe that you are trying to comply. I had to use mine at Castle Combe.
Do remember that the track guys are all petrol heads themselves, and wouldn't dream of applying noise limits. It's the local councils who are monitoring the noise levels and applying limits. For example, Bedford's drive by noise meters are set to 87.5 dB (but are 10 metres from your car) and are connected direct to the council offices.
Can I just say that I don't know your track driving experience, but Castle Combe wouldn't be my first choice of beginner's track - It's basically a bumpy high speed track consisting of four corners, two chicanes and straights. The four corners have armco barriers literally 5 metres off the track - no room for error. The first time I drove it I was definitely shocked at the lack of run-off, and it took me until the afternoon to get up to speed - and it was my 25th track day at a variety of tracks. I survived.
On my subsequent outings, at Mallory Park and Hullavington, I left the track on both days at over 100 mph (brain failure at Mallory, brake failure at Hullavington) and was extremely grateful for the space available.
mk1fan said:
As TV8 said above, pop along to your local track during a trackday and they will happily measure your car. You don't have to be on the trackday. They are run regularly - not always by the track owners so call the track and ask.
That said, the same car can read differently depending on a lot of factors so a 100dB reading on August 1st could be 102dB on December 1st. The idea of the above is to see if you need to do anything about it.
If the car reads borderline, then look at getting (buy or borrow) some trackday cans. There are loads to choose from and don't need to be pretty just secure.
Are you going to do a lot of trackdays?
From what you say and what everyone else has said I think I'll do just that, call up and ask, and if needs be swing by there and get it checked first. I'm pretty sure the TVRCC holds trackdays at Combe on occasion so I'm sure it'll be fine!That said, the same car can read differently depending on a lot of factors so a 100dB reading on August 1st could be 102dB on December 1st. The idea of the above is to see if you need to do anything about it.
If the car reads borderline, then look at getting (buy or borrow) some trackday cans. There are loads to choose from and don't need to be pretty just secure.
Are you going to do a lot of trackdays?
I plan to do one every couple of months through the summer, so only three or four, can't really afford to do much more than that!
Chimaera27 said:
Thanks for the heads up, I have watched the video on the website and it does look fast. I have no track day experience to speak of, but I used to race karts competitively and I've raced Formula Mazda so now how to drive fast, but it is a new circuit to me so I'll bear what you say in mind. I didn't know Hullavington had track events, they any good?
Unfortunately Hullavington isn't available anymore - Motorsport Events used to use it, but not now.Bob
Chimaera27 said:
Prizam said:
No pre-cats and sleeved came out at 115db at Combe for me.
That's pretty boomy, did they let you on anyway?To be honest, i think the guy doing it was a jobs worth. Plenty of pops and bangs aswell to mes up the result.
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