Bedford in an E46 M3 'CSL' - OK for noise?
Discussion
Hi all,
After a very long hiatus (15 years ish!) I fancy getting back into Track Days and have recently bought a rather nice E46 M3, which has a CSL airbox and Tegiwa backbox (as used on the M3 cup cars). It's quite loud, the vast majority of which is induction noise. I have booked Bedford GT for next month with MSV, but have since read that they're very strict on noise. Has anyone taken a E46 M3 CSL to Bedford and got past the noise meter OK?
I read on the MSV website that it's 87.5dB driveby measured at 20metres, which equates to 113dB at 1m, and I can't see anyway that my car is anywhere near that loud?
Any input greatly welcomed.
After a very long hiatus (15 years ish!) I fancy getting back into Track Days and have recently bought a rather nice E46 M3, which has a CSL airbox and Tegiwa backbox (as used on the M3 cup cars). It's quite loud, the vast majority of which is induction noise. I have booked Bedford GT for next month with MSV, but have since read that they're very strict on noise. Has anyone taken a E46 M3 CSL to Bedford and got past the noise meter OK?
I read on the MSV website that it's 87.5dB driveby measured at 20metres, which equates to 113dB at 1m, and I can't see anyway that my car is anywhere near that loud?
Any input greatly welcomed.
I think your calculations are somewhat out - 113db is crazy crazy high, I think only Donington loud days would let any car on with that level of noise. As far as I remember, the drive by microphones at Bedford are closer than 20 metres - nearer to 10.
They are very visible, so easy to avoid being at max revs as you pass them.
With a decatted V8 TVR I used to struggle with the 101db static, but never had a problem with the 87.5 db drive by.
They are very visible, so easy to avoid being at max revs as you pass them.
With a decatted V8 TVR I used to struggle with the 101db static, but never had a problem with the 87.5 db drive by.
The staff at Bedford are very helpful regarding noise violations and do want to help you stay out on track!
I have a TTRS with stock exhaust; I easily pass the static with valves closed (with valves open I’m at 100db!) The recurring problem I had the three times I’ve been there was triggering the sensor after turn one (on the left) but none of the others. It turned out to be my shift point was in line with the sound meter and the “crack” was setting it off so I ended up short shifting at that point and had no further issues!
Pic attached from video showing Marshall with “NOISE” board.
If you are under static you should be ok on drive by.
I have a TTRS with stock exhaust; I easily pass the static with valves closed (with valves open I’m at 100db!) The recurring problem I had the three times I’ve been there was triggering the sensor after turn one (on the left) but none of the others. It turned out to be my shift point was in line with the sound meter and the “crack” was setting it off so I ended up short shifting at that point and had no further issues!
Pic attached from video showing Marshall with “NOISE” board.
If you are under static you should be ok on drive by.
Thanks everyone. Unfortunately, I’m not really particularly close to any tracks to get my car tested prior to the event, so I think I’ll just have to wing it and try doing a static test myself. The exhaust is quite fruity, but the induction noise when the engine is on the load is likely to be the bigger issue I think, but if a standard CSL passes, then hopefully mine will be ok.
Does anybody know how accurate an iPhone dB app might be?
Does anybody know how accurate an iPhone dB app might be?
The problem with phone noise meter apps is that most phones have automatic gain control on the microphone, which can't easily be overridden. They tend not to be able to read over 85dB.
To get around this, measure at a greater distance, so if the limit is 100dB at 1/2m, you need to be under 82dB @ 4m.
To get around this, measure at a greater distance, so if the limit is 100dB at 1/2m, you need to be under 82dB @ 4m.
Well I did a little bit of basic iPhone testing yesterday and I am pretty convinced that I’m not going to pass a static test. It measures 95dB at 4m and 101dB at 2m, so way off where I need it to be, even if the iPhone app isn’t very accurate. These guys are fairly local so I’m going to pop in next week and see if they can tame down the current exhaust a little.
http://simpsonraceexhausts.com/
On a positive note, the car sounds amazing from outside! Never heard it before....
http://simpsonraceexhausts.com/
On a positive note, the car sounds amazing from outside! Never heard it before....
Galahad said:
Thanks everyone. Unfortunately, I’m not really particularly close to any tracks to get my car tested prior to the event, so I think I’ll just have to wing it and try doing a static test myself.
That's a real shame Chris as it's probably the most definite way to know particularly if it's a MSV track. Are you far from Brands? nickfrog said:
Galahad said:
Thanks everyone. Unfortunately, I’m not really particularly close to any tracks to get my car tested prior to the event, so I think I’ll just have to wing it and try doing a static test myself.
That's a real shame Chris as it's probably the most definite way to know particularly if it's a MSV track. Are you far from Brands? https://www.youtube.com/watch?v=a8PHZlIXgL8
Noise clip which recorded when trying to measure the dBs.
Noise clip which recorded when trying to measure the dBs.
Galahad said:
Sadly about 70 mins from Brands and 90 mins from Bedford.
I am over an hour from Cadwell Park, but felt it was worth the drive to get an official view on my noise levels before investing getting on for £200 on a track day, and the same amount of time getting there for no purpose if I did fail.But then, every trip in a TVR is a joy.......
Changing the subject, TVR owners can buy bolt on track day silencers that lose about 7 dB and make the sound more mellow. Does the same kit exist for people who drive E numbers? They say they can make these for any car, but beware pairs of tail pipes that are close together.
link to TVR track say silencers website
Galahad said:
As luck would have it, I now have a meeting in Huntingdon tomorrow morning, so can call into Bedford mid morning. It looks like they have a Palmersport day on - if I drop in, are they likely to test my car quickly for me?
Due to COVID restrictions you would be wise to call them first. Also, Palmersport days use the track's own cars, so they might not have the noise testing equipment readily to hand
QBee said:
Due to COVID restrictions you would be wise to call them first.
Also, Palmersport days use the track's own cars, so they might not have the noise testing equipment readily to hand
You're quite right, I would call them. But they do have the equipement to hand, although perhaps not the ressources or inclination atm. Also, Palmersport days use the track's own cars, so they might not have the noise testing equipment readily to hand
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