EJH911 Posted February 20, 2007 Share Posted February 20, 2007 Hi, I am thinking of tracking my car for the first time and was wondering if anyone knew the noise a 3.2 is likely to make: 1 With the standard exhaust in place 2 With an H&S (single exit) and pre-silencer bypass pipe. Some friends are looking into Goodwood (convenient for those of us in the Channel Islands) and I was wondering if I had any chance of being under their 105db noise restriction. Any thoughts? Link to comment Share on other sites More sharing options...
stevecwalters Posted February 20, 2007 Share Posted February 20, 2007 Hi, I am thinking of tracking my car for the first time and was wondering if anyone knew the noise a 3.2 is likely to make: 1 With the standard exhaust in place 2 With an H&S (single exit) and pre-silencer bypass pipe. Some friends are looking into Goodwood (convenient for those of us in the Channel Islands) and I was wondering if I had any chance of being under their 105db noise restriction. Any thoughts? With a standard set-up I would imagine you would be well within. My 944 was well within and my standard 84 911 is around the same level. Production cars made for the street are almost certainly going to be within this limit. But I would be interested to know from others exactly how you find out before you pitch up at the circuit and are not allowed to run becuase you are too loud... Steve Link to comment Share on other sites More sharing options...
AirCooledExcellence Posted February 20, 2007 Share Posted February 20, 2007 Well I didn't get told off on Sunday! (pre silencer bypass & M&K back box) and there were plenty of cars louder than mine there. Snet has a 106db limit IIRC. Link to comment Share on other sites More sharing options...
EJH911 Posted February 20, 2007 Author Share Posted February 20, 2007 I have been emailing Goodwood to ask about the booking I might be making (6 or so of us going) about this and they say, "We test a metre from the exhaust. We have to be very strict with our noise limit here as we are heavily monitored by the council." They have been a pleasure to deal with and all my (remarkably dumb) queries have been dealt with very swiftly. I now need to find a noise-measuring device. Any ideas? Link to comment Share on other sites More sharing options...
Andre Posted February 20, 2007 Share Posted February 20, 2007 I have been emailing Goodwood to ask about the booking I might be making (6 or so of us going) about this and they say, "We test a metre from the exhaust. We have to be very strict with our noise limit here as we are heavily monitored by the council." They have been a pleasure to deal with and all my (remarkably dumb) queries have been dealt with very swiftly. I now need to find a noise-measuring device. Any ideas? Goodwood are very strict in my experience - a metre from the rear of a rear engined car and abosolutely no leeway... Castle Coombe less so, though they have the same 105db limit on some days. Never been noise tested at Brands.... I would definately get noise tested before you book. Andre Link to comment Share on other sites More sharing options...
oliverjamesthomas Posted February 20, 2007 Share Posted February 20, 2007 You definitely shouldn't have any problems with the standard set up and I wouldn't think your other option will cause problems either. The key is to make sure the car is warm when it's tested, because the difference between a warm engine and a cold engine noise wise, is significant. 105dB is actually very loud and I would have thought you'd be hard pressed to get there. Also, if they're not lining you all up for a static test, park away from the buildings and other cars to aid your cause. For reference, I was behind a Cup Car at Oulton last year and that hit 104dB in the pit-lane noise test. Link to comment Share on other sites More sharing options...
stevecwalters Posted February 20, 2007 Share Posted February 20, 2007 Goodwood are very strict in my experience - a metre from the rear of a rear engined car and abosolutely no leeway... Castle Coombe less so, though they have the same 105db limit on some days. Never been noise tested at Brands.... I would definately get noise tested before you book. Andre Just had a quick google and can't seem to find anything that would be cheap enough to warrant buying. It may be that, given the strictness of local councils these days, they would almopst certainly have a hand held meter that you might persuade someone to use on your car. This site provides a little reassurance but no definite information. Steve Link to comment Share on other sites More sharing options...
bruceb Posted February 20, 2007 Share Posted February 20, 2007 I have been emailing Goodwood to ask about the booking I might be making (6 or so of us going) about this and they say, "We test a metre from the exhaust. We have to be very strict with our noise limit here as we are heavily monitored by the council." They have been a pleasure to deal with and all my (remarkably dumb) queries have been dealt with very swiftly. I now need to find a noise-measuring device. Any ideas? Be careful at Goodwood as they are very strict on noise and it depends who is organising the day as to what the limit is. PCGB run some days there and IIRC they have a 105db limit with 6 cars on circuit, My SC normally checks out at about 102db and I have had no problems. Some track day organisers offer 98db days and I know that even with an additional bolt on "can" silencer I can only just get below the 100db mark. A standard 3.2 is unlikely to be much quieter than 100db and I would be worried about making the 98db limit. One of the problem seems to be the general engine noise from air cooled 911's which contribute considerably to the noise test reading. Goodwood is a great circuit to drive and its very fast, its not modern however so some of the run off is a bit limited. If the noise proves to be a problem you could also consider Brands in Kent and Castle Coombe in Wiltshire which are a lot easier on the noise testing and not too far from channel ports, plus of course they are current race circuits that have kept pace with the equiremntsfor greater run off areas. What ever you decide they are all great circuits to drive in a 911 Link to comment Share on other sites More sharing options...
Andre Posted February 20, 2007 Share Posted February 20, 2007 The key is to make sure the car is warm when it's tested, because the difference between a warm engine and a cold engine noise wise, is significant. 105dB is actually very loud and I would have thought you'd be hard pressed to get there. Also, if they're not lining you all up for a static test, park away from the buildings and other cars to aid your cause. Good advice! Link to comment Share on other sites More sharing options...
siggy Posted February 20, 2007 Share Posted February 20, 2007 Your local environmental health office should have one or find out who runs the local Hill climb (IIRC they do run them there) Link to comment Share on other sites More sharing options...
AirCooledExcellence Posted February 20, 2007 Share Posted February 20, 2007 BTW, Some track day organisers will hire out a sound meter so you can test at home, bookatrack springs to mind. Only about £15 IIRC they post it out to you, you post it back when you're done. Link to comment Share on other sites More sharing options...
mudplugger Posted February 20, 2007 Share Posted February 20, 2007 Beware bypass pipes they do increase noise alot. With standard heat exchangers stainless cat bypass and 3inch twin outlet back box mine read 108db Now running with super traps from demon tweeks and can get down to 105 but thats about it. Also I have carbon airbox which adds alot to induction noise. Still feel its unfair on aircooled engines, there definatley was louder cars on track but the static noise test is a real bugger. Link to comment Share on other sites More sharing options...
Richard Bernau Posted February 20, 2007 Share Posted February 20, 2007 I have a noise meter It cost all of about £30 from tooled-up.com IIRC and has proven very accurate, though you have to have it on the correct setting (unlike when I had it at WRC). I can post it out but need it for the next couple of weeks. The static noise testing procedure is pretty std everywhere subject to user error - 3/4 max revs, 1 metre from the tail pipe at 45 degrees to the outlet. A std 3.2 will register about 98db, though any small leaks will effect this enormously. I was at 104db with a small leak in the crossover pipe. My old SSI and M&K 2-out was 105db even with downturns. A std 3.2 will be borderline for a 98db day but should make it. 964s with the cup bypass pipe or G pipe will be in the 103-105db range. I am surprised that mudplugger was 108db as that is quite loud but sometimes cars don't sound as loud as the meter says. My friend had a 2.7RS engine with a std RS silencer tested at 109db at Goodwood. With a warm engine and a bolt on can it came down to 105db. Didn't sound too loud during either test. As well as having the engine fully warm, you should depress the clutch. I also recommend you bring the revs up slowly and cheat as much as possible. First, use 4500rpm as 3/4 max regardless of what your redline is. Second try to use 4300rpm or 4400rpm if you can get away with it. It makes a difference. Yes, the static tests are unfair on rear engine cars as they pick up all the induction noise and cooling fan noise. The driveby test is normally ok in our cars and downturn pipes or bolt on mufflers normally do the trick. In my experience, Goodwood is very strict and Castle Combe is also - they have a reputation for being the noise *beep* and also do the 6 cars on track thing. It makes a boring track day without much track time IMHO. Bedford is also pretty strict now and has drive by tests as well as static. Once you know where the drivebys are you can lift for them but they can be a pain. Bottom line is a std well maintained car will be fine so don't worry. RB Link to comment Share on other sites More sharing options...
mudplugger Posted February 20, 2007 Share Posted February 20, 2007 alot of cars where reading higher on the last trackday, it was very cold with still air which must make a difference, there was lots of mumbling and arguing with the scrutineer from lots of people Aparently the db meter had been re-calibrated probably not that acurately and cars that normally had no problem passing the test where failing. No point in arguing with the scrutineer they have a very valid job to do and must keep the tracks operating licence. Blame the NIMBYS who annoy the **** out of me with their noisy mowers on a nice summers afternoon or their very loud barbecues. Link to comment Share on other sites More sharing options...
EJH911 Posted February 20, 2007 Author Share Posted February 20, 2007 Thanks for all your advice on this; everyone has been very helpful. Am going to try some friends of friends who are surveyors etc and if that fails I know some people who (I think) have links to the hillclimbing people so I'll try them too. The H&S is ordered but has neither been shipped nor fitted yet; this will be fitted regardless. If it's too noisy and can't be tracked in the UK after that (possible) I will go and sit under a tree with a book in the south of France for a summer holiday instead (with the car, naturally). If all else fails I can always go to a track in France (quite a few trips booked from over here) as I don't think they're quite as particular about such matters. Link to comment Share on other sites More sharing options...
Richard Bernau Posted February 21, 2007 Share Posted February 21, 2007 Thanks for all your advice on this; everyone has been very helpful. Am going to try some friends of friends who are surveyors etc and if that fails I know some people who (I think) have links to the hillclimbing people so I'll try them too. The H&S is ordered but has neither been shipped nor fitted yet; this will be fitted regardless. If it's too noisy and can't be tracked in the UK after that (possible) I will go and sit under a tree with a book in the south of France for a summer holiday instead (with the car, naturally). If all else fails I can always go to a track in France (quite a few trips booked from over here) as I don't think they're quite as particular about such matters. All IMHO, but..... If the air enters on the LHS from the pre muff and exits on the LHS - ie it has to do a u-turn in the muffler - you will be fine at a 102db day with any aftermarket muffler. 105db will be easy peasy. Straight pipe replacing pre-muff will still be OK at 105db. It is only when you have a RHS second outlet so the exhaust is really going straight thru the muffler that the std config exhaust starts to give noise problems. Any of the 2-in exhausts are noisy, even 2-in, 1-out with a std silencer is relatively noisy. If all else fails, make sure you have some thin stainless wire and a big brick of wire wool together with some little holes drilled near the end of the tailpipe. Stuff the wire wool up the tail pipe and use the thin wire to criss-cross the tailpipe so it doesn't come flying out. Lasts for about 5 minutes and saves you a db or 2. Often enough for the static test. Or buy a bolt on silencer for emergencies from Merlin Motorsport. RB Link to comment Share on other sites More sharing options...
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