Std 996 GT3.... 108db!!!
Discussion
Arrived at an MSV track day at Snetterton last Monday and went off for noise testing not expecting any issues having passed a similar 105db test at Brands in November last year.
Asked to rev to 6000rpm and tested at 108db
Car is 996 mk2 which has done 48k and exhaust is to the best of my knowledge standard although the lambda sensor on exit cat has triggered several times suggesting the baffles in the cat/exhaust starting to fail? (passed MOT with no issues recently).
Car had just been out on the sighting laps so should have been upto temperature.
Thinking I had a long drive back to Kent I discussed it with a fellow Porsche owner (Wayne - Oz996 on 911uk) then took it for a run up the by-pass and made sure it was fully warmed up and that all ancillaries were switched off before going for a re-test. On Waynes advice I also pulled up away from the fuelling/noise test hut to avoid any reverberation from that. Unfortunately I think my foot slipped off the accelerator a bit and I only went to 5300 ish. The tester ummed and arhhed and gave me benefit of the doubt and showed me 105db on his paperwork, so I was able to play after all
Just a word of warning really to those who think they wont have any issues, it may be worth getting tested at your local circuit prior to travelling any distances to another track!
I have a 105db track day booked at Castle Combe in June and I am aware they are very strict on noise. What are my options?? New exhaust/cat/bolt on silencers??
Asked to rev to 6000rpm and tested at 108db
Car is 996 mk2 which has done 48k and exhaust is to the best of my knowledge standard although the lambda sensor on exit cat has triggered several times suggesting the baffles in the cat/exhaust starting to fail? (passed MOT with no issues recently).
Car had just been out on the sighting laps so should have been upto temperature.
Thinking I had a long drive back to Kent I discussed it with a fellow Porsche owner (Wayne - Oz996 on 911uk) then took it for a run up the by-pass and made sure it was fully warmed up and that all ancillaries were switched off before going for a re-test. On Waynes advice I also pulled up away from the fuelling/noise test hut to avoid any reverberation from that. Unfortunately I think my foot slipped off the accelerator a bit and I only went to 5300 ish. The tester ummed and arhhed and gave me benefit of the doubt and showed me 105db on his paperwork, so I was able to play after all
Just a word of warning really to those who think they wont have any issues, it may be worth getting tested at your local circuit prior to travelling any distances to another track!
I have a 105db track day booked at Castle Combe in June and I am aware they are very strict on noise. What are my options?? New exhaust/cat/bolt on silencers??
every track seems to differ in what db they say your car is, i dont think 1 track gets the meters calibrated when they are supposed to. i was 105 at anglesey, up to 108 at brands and back to 103 back at anglesey? on a return visit 2 months later.i wasnt going to be able to race at combe when my old gt2 was 110db and they allowed 108 on gt cars in 2009. after the carbon silencers set on fire in qualifying and i had to fit my old smaller silencers, they made me re test for the race. i did the same laying off the revs and got away with it.we went on to win the annual ferrari v porsche that day. for the next meeting i put a switchable resister on the rev counter input wire so it read higher than the actual revs i was doin.
it sounds bad but i couldnt get any larger silencers across the back of the car. the fan on the aircooled cars is very noisy at 6k for the ststic noise test as are the 1000cc injectors.
i wasnt causin any trouble either as the car on track was quite quiet and always passed the drive by tests as the noise test machines are a lot further away than the static pre track test 1s, so they dont pick up all the other engine noises. you could go the expensive silencer route or you could cheat the rev counter, still pass the drive by and cheat like me haha
regards mark
it sounds bad but i couldnt get any larger silencers across the back of the car. the fan on the aircooled cars is very noisy at 6k for the ststic noise test as are the 1000cc injectors.
i wasnt causin any trouble either as the car on track was quite quiet and always passed the drive by tests as the noise test machines are a lot further away than the static pre track test 1s, so they dont pick up all the other engine noises. you could go the expensive silencer route or you could cheat the rev counter, still pass the drive by and cheat like me haha
regards mark
The noise tester said that they dont normally have any issues on the drive-by, just the static test.
Trouble is Castle Combe is a couple hours away from me as well, so dont know whether to risk it...
I suspect the baffles are starting to blow out a bit, although it doesn't sound particularly loud normally.
The other 996 C2 at Snetterton tested at 102db, which he said was normal for his car, although purposely ensured he was well away from the fuelling hut.
Trouble is Castle Combe is a couple hours away from me as well, so dont know whether to risk it...
I suspect the baffles are starting to blow out a bit, although it doesn't sound particularly loud normally.
The other 996 C2 at Snetterton tested at 102db, which he said was normal for his car, although purposely ensured he was well away from the fuelling hut.
My 996.2 was 101dB static at Bedford. The guy asked what the red line was so I said 8000rpm he then decided I should static test at 4000rpm. I reacon if you go above this rpm it comes onto cam and gets much louder. Mine has 48k miles. I was pleased not to get black flagged but wonder now if I may be too loud elsewhere, I would hate to spend all that dosh and get sent home.
Just been reading the Donington thread and Far Coughs comments about being black flagged. Seems like it's becoming more and more of an issue. The car sounds great and I really dont want to spend loads on new boxes if it doesn't need them.
I know Mike at Sports & Classic had some additional rear silencers made by cargraphic, but is anyone aware of some universal jobbies that are reasonable money and will not affect performance and or damage the car and it's current system???
I know Mike at Sports & Classic had some additional rear silencers made by cargraphic, but is anyone aware of some universal jobbies that are reasonable money and will not affect performance and or damage the car and it's current system???
stroller said:
Just been reading the Donington thread and Far Coughs comments about being black flagged. Seems like it's becoming more and more of an issue. The car sounds great and I really dont want to spend loads on new boxes if it doesn't need them.
I know Mike at Sports & Classic had some additional rear silencers made by cargraphic, but is anyone aware of some universal jobbies that are reasonable money and will not affect performance and or damage the car and it's current system???
Mikes cans are the best i've seen by the way of performance & value.. I'm sure he could help you get some knocked up... they are excellent!I know Mike at Sports & Classic had some additional rear silencers made by cargraphic, but is anyone aware of some universal jobbies that are reasonable money and will not affect performance and or damage the car and it's current system???
A "universal" product:
Supertrapp:
http://www.demon-tweeks.co.uk/Product.do?method=vi...
It does work, but also kills the top end power
Supertrapp:
http://www.demon-tweeks.co.uk/Product.do?method=vi...
It does work, but also kills the top end power
Oh, and maybe you could replace the standard tips with 60-90 degree angled sections pointing downwards?
This solution has been used on 997 race cars specifically to reduce noise propagation. Can't remember which type, but I saw it in photographs of race cars in a thread here about one of the Porsche Cup UK meets - last summer I think?
As shown here:
This solution has been used on 997 race cars specifically to reduce noise propagation. Can't remember which type, but I saw it in photographs of race cars in a thread here about one of the Porsche Cup UK meets - last summer I think?
As shown here:
Edited by anonymous-user on Tuesday 22 May 14:15
I know there is variation in testing, but if you are reading 108db (true reading) then you might want to get your exhaust and manifolds checked out. You already pointed out post cat that you had a few o2 issues, on top of which if your cats are bad, they can also lose you power as well - have seen that first hand.
Seems you are looking for aftermarket solution when the solution might be to fix the car.
Remember variocam plus high lift comes in just over 5000 rpm so noise levels increase above this. And iirc on a warm start in cold weather it goes straight to highlift mode anyway, hence why driving around for a while will also help.
Mike @ S&C has an aftermarket exhaust which is why his is loud, hence his need for aftermarket solution.
Ken
Seems you are looking for aftermarket solution when the solution might be to fix the car.
Remember variocam plus high lift comes in just over 5000 rpm so noise levels increase above this. And iirc on a warm start in cold weather it goes straight to highlift mode anyway, hence why driving around for a while will also help.
Mike @ S&C has an aftermarket exhaust which is why his is loud, hence his need for aftermarket solution.
Ken
Edited by 996ttalot on Tuesday 22 May 14:43
Just an additional word of caution as well, I failed the noise test at snetterton after passing at Brands a few months earlier in my 993, I live at Brands so Snet is a 2 hour drive plus a days holiday so not best pleased.
Anyway, I went into the MSV office and explained that I had failed the noise test and couldnt go out on track and asked what the refund procedure was, I didnt think for one minute I would get my money refunded so suggested a credit note to another MSV event at some stage in the next few months.
I was told to speak to the office which is based at Brands.
Plenty of email back and forth and long story short ..... unlucky mate !!
So £200+ track day, 4 hours and £70 ? fuel, and the kick in the nuts days holiday allowance lost.
Dont even think about Castle Coombe unless your sure you will pass.
Oh and pm me if you need a set of used (8000 mile) GT3 cats cheapo :-)
Anyway, I went into the MSV office and explained that I had failed the noise test and couldnt go out on track and asked what the refund procedure was, I didnt think for one minute I would get my money refunded so suggested a credit note to another MSV event at some stage in the next few months.
I was told to speak to the office which is based at Brands.
Plenty of email back and forth and long story short ..... unlucky mate !!
So £200+ track day, 4 hours and £70 ? fuel, and the kick in the nuts days holiday allowance lost.
Dont even think about Castle Coombe unless your sure you will pass.
Oh and pm me if you need a set of used (8000 mile) GT3 cats cheapo :-)
Went up to Snetterton in a 599 two weeks ago and static tested at ~110db at 6k revs. Looked like we weren't gunna get on but had a word with the track manager on the day and he said we could go out, short shift a bit and see how the fly-by tests came out.
After half a day of short shifting, spoke to the guy in the tower who said our fly-by tests were perfectly within limits. Red-lined it from then on with no issue.
Edit - As for Castle Coombe, I wouldn't bother.
After half a day of short shifting, spoke to the guy in the tower who said our fly-by tests were perfectly within limits. Red-lined it from then on with no issue.
Edit - As for Castle Coombe, I wouldn't bother.
Edited by Complex on Tuesday 22 May 15:45
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