Noise - Trackdays - My 3.2

[TopCarrera]

I'm hoping to do a few more track days this year (bit of a novice). Noise seems to be a bigger issue than I had anticipated. Last year I was OK at Castle Coombe and at Bedford I was told that I was near the static limit (101 db I think - surprised at this) but well within their drive by noise limit requirment (they state below 87db I think but this seems very low?).

I am keen to do Donnington (there are places left for this Saturday). A 98db drive by limit is the requirement. Reading threads on Pistonheads etc.. it would seem that the noise regs at Donnington are enforced quite vigourously by the authorities.

I have an 84 car with a sport final box (not sure what make) with a single 3" outlet pipe. The car is a little noisier than standard but not as raucous as cars Ive heard fitted with twin outlet systems and quieter than most 964 RSs that I've seen and heard at trackdays ..........

Has anybody got any experience of Donnington? I am worrying unduly?

 

[Guest]

I've lost count of the number of track days I've done in Caterhams, none in my new toy, but in my experience most tracks are rigorous in enforcing the noise levels. I remember Goodwood had microphones around the perimeter, connected to the local council and Castle Coombe have had problems with neighbours for years (even though the track was there before they moved in). If there is a track day going on near you, I am sure the organiser wont mind testing the noise of your car, especially if they think you will soon be a customer of theirs. It would'nt take them 2 minutes to use their noise meter.

 

[Andy Tims]

Andrew

Not sure if this helps, but I have a standard exhaust. I only just get on at Combe & did not have a problem at Donington.
With a sports box you may well be just over. As Jeremy says get tested as soon as you can.
You can by mufflers to fit on the day, but not sure how much they
a) Reduce the noise by.
b) Impact performance.

 

[38F3E1]

ORIGINAL: TopCarrera

I am keen to do Donnington (there are places left for this Saturday). A 98db drive by limit is the requirement. Reading threads on Pistonheads etc.. it would seem that the noise regs at Donnington are enforced quite vigourously by the authorities.

Yes they are strict. They have noise meters around the circuit (I think three which I believe are movable so you don't know where they are) plus the council has some set up in the outlying villages to make sure noise regs are being followed.

Ian.

 

[TopCarrera]

Bookatrack are organising the event. (£150- open pit lane).

I have spoken to one of the officials who suggested that if I was OK at Bedford then I should be fine.

I think I should be OK so I have taken the risk and gone ahead and booked a place for Saturday.

Hopefully the weather should stay dry and bright.

 

[Guest]

Have a great day. See if you can take the Craner Curves without lifting, it's the only way to appreciate that the colour of adrenalin is brown[]

 

[38F3E1]

ORIGINAL: TopCarrera

Bookatrack are organising the event. (£150- open pit lane).

I have spoken to one of the officials who suggested that if I was OK at Bedford then I should be fine.

I think I should be OK so I have taken the risk and gone ahead and booked a place for Saturday.

Hopefully the weather should stay dry and bright.

I have just booked as well so I will look out for you to say hello. I'll be in an old yellow 2.4E. Weather forecast looks good so far.

Ian.

 

[Guest]

ORIGINAL: Andy Tims

Andrew

Not sure if this helps, but I have a standard exhaust. I only just get on at Combe & did not have a problem at Donington.
With a sports box you may well be just over. As Jeremy says get tested as soon as you can.
You can by mufflers to fit on the day, but not sure how much they
a) Reduce the noise by.
b) Impact performance.

1-2db reduction, costs about £50 and zero performance impact as they are straight thru mufflers.

A basically std 3.2 system should be fine everywhere. Std is 97-98db on the static test. Check for leaks in the x-over pipe as this is hard to hear but increases dbs dramatically - ask me how I know. Also, ensure the engine is warm and the clutch is depressed to get the min reading. Bring the revs up slowish not sharply to 4500rpm or a touch less if you can get away with it.

911s get screwed on the static test being rear engined and usually fly past the drive by tests. If you fail, ask them to take it into consideration. I got on to Castle Combe this way.

I have my own noise meter now and can lend it out, but it is booked out next week to Jacob Snell. I am out of the country most of Feb but Jacob could forward it on to other interested parties.

 

[bruceb]

Just to back up Richards comments, my SC with the backdated exhaust (SSI) and oem 74 carrera rear silencer regularly registers at 101-103db on the noise meter. I fitted one of the clamp on rear silencers and this reduced noise to the 100db limit, just. Again no effect on power at all.

Interestingly on one day there was a old 2.4 with an all stainless standard exhaust that was over 104db. The clamp on silencer had virtually no effect at all on the recored noise levels and the unlucky driver missed the track day, very sad!


Bruce
83Sc

 

[Guest]

Yes, MFI engines are noisy regardless of the exhaust. I have a friend with a 2.7RS spec engine that just got to 105db with a bolt on silencer. His current 2.8RS engine registers 109db and almost gets to 105db with 2 bolt-on cans. He got it on to a noisy Castle Combe day - just. On the track, it sounds noisy but not stupidly so.

I am stuck around 105db with SSIs and 2 out muffler. I am going to use downturns before I look at bolt-on mufflers. This probably gives you a similar reduction and should be sweet for drive-by meters. I am not a big fan of having a couple of pounds of scrap iron bolted on the end of the tailpipe unless I have to.

 

[TopCarrera]

Trackday at Donnington was good fun, except for an icy start and an Ariel Atom (amongst others) that seemed to enjoy leaving the circuit and halting proceedings! Will definitely do again in a few weeks time - fantastic circuit, I just need more time to gain confidence.

On the subject of noise I think I was previously worrying unduly but the concern is that at circuits with tight static tests (eg Goodwood, Castle Coombe) I still might be close.

Where do I find a muffler that would bolt onto a 3" diameter outlet pipe? How £ much, and how easy would it be to fit at the track if I needed it (i.e. only if I failed noise test). How heavy and would this put excessive load on back box/system?

 

[bruceb]

I got my clamp on silencer from

http://www.merlinmotorsport.com

My SC failed the noise test on a Coombe day, the chaps at Merlin located at the circuit let me try the clamp on silencer first to check that it would reduce the noise enough with the testers. Luckily it did so my day was saved

Bruce

 

[Guest]

ORIGINAL: TopCarrera

Trackday at Donnington was good fun, except for an icy start and an Ariel Atom (amongst others) that seemed to enjoy leaving the circuit and halting proceedings! Will definitely do again in a few weeks time - fantastic circuit, I just need more time to gain confidence.

On the subject of noise I think I was previously worrying unduly but the concern is that at circuits with tight static tests (eg Goodwood, Castle Coombe) I still might be close.

Where do I find a muffler that would bolt onto a 3" diameter outlet pipe? How £ much, and how easy would it be to fit at the track if I needed it (i.e. only if I failed noise test). How heavy and would this put excessive load on back box/system?

You have most of the answers but just to reassure, they are fine to clamp on the pipe of most silencers - no undue worries about weight or load on the muffler. If you have a lightweight muffler (like mine) then its a bit more dubious, however M&K make a light bolt on stainless silencer if you think the heavy Merlin ones are too much.

RB

 

[38F3E1]

ORIGINAL: TopCarrera
Trackday at Donnington was good fun, except for an icy start and an Ariel Atom (amongst others) that seemed to enjoy leaving the circuit and halting proceedings!   Will definitely do again in a few weeks time - fantastic circuit, I just need more time to gain confidence.

Plus a number of other numpties who managed to spin by clipping the inside of Craner Curves thereby throwing clods of mud all over the track. Eek! The afternoon once the track was completely dry was great but the morning was very frustrating (although entertaining watching all the spinners) with all the red flags. The Ariel Atom came past me once just before the back end of the circuit (the old hairpin?) and as I turned into the corner there he was facing me in the middle of the track. Fortunately because it was slippy I wasn't pushing too hard.

BTW my 2.4 MFI engine was absolutely fine on noise. That's twice it has not had a problem there.

Ian.

 

[Guest]

I have just booked my first (novice) trackday but am now worried about my exhaust. I am doing a day at Brands with a 105dB limit.

At my last service I was told my heat exchanger flanges were worn and would need replacing before my next MOT. Will this be a problem for the noise, do you think?

 

[bruceb]

Simon

As long as your system is in good overall condition with no leaks you will have no problems with the 105db noise limit.

I am not sure what can go wrong with exhaust flanges in particular, however on my first track day with my car the exhaust did start to leak on one of the crossover joints. The extra heat on corroded flanges and retaining bolts was enough to blow the seal. I would recommed that the joints are checked for corrosion and that the system is in generally good condition, other than that I would not worry and go and enjoy the day

Bruce