A question for Uk 964 gang db readings
03-10-2012, 06:31 AM
#1
Burning Brakes
Thread Starter
A question for Uk 964 gang db readings
Yesterday was supposed to be my first trackday in the 964 so after a 200 mile trip and overnight accommodation I did the sighting laps then went to get the Noise test done and it was an epic fail @107db
The only thing I have changed is the exhaust final silencer to a G-pipe so have any of you had this issue at a UK circuit
I really could kick myself as if I had taken the final silencer with me it would have been a 15 min job to salvage the day
The only thing I have changed is the exhaust final silencer to a G-pipe so have any of you had this issue at a UK circuit
I really could kick myself as if I had taken the final silencer with me it would have been a 15 min job to salvage the day
03-10-2012, 06:36 AM
#2
I have a G Pipe fitted and had no problem in the drive by test at Donnington park so you must have been really unlucky or revved to hard! I thought it was generally accepted that a G pipe on its own would pass a 105db test. Bad luck
03-10-2012, 08:20 AM
#3
Yesterday was supposed to be my first trackday in the 964 so after a 200 mile trip and overnight accommodation I did the sighting laps then went to get the Noise test done and it was an epic fail @107db
The only thing I have changed is the exhaust final silencer to a G-pipe so have any of you had this issue at a UK circuit
I really could kick myself as if I had taken the final silencer with me it would have been a 15 min job to salvage the day
The only thing I have changed is the exhaust final silencer to a G-pipe so have any of you had this issue at a UK circuit
I really could kick myself as if I had taken the final silencer with me it would have been a 15 min job to salvage the day
I have a CatBypass and G-Pipe and was fine at Donnington also, which was 105db drive by. With just a catbypass I registered under 98db static at Castle Combe. Was your test static?
03-11-2012, 07:10 AM
#7
Its a total bummer when that happens eh!
Was the engine hot or cold/warm during the test? 5200 rpm isnt far off whats needed for 75% throtlle (6800*.75=5100) so in the right ballpark.
You can generally kill a few DB on the static test by getting it very hot with lots of low gear high rpm runs - saved the bacon of a few of our group at various UK trackdays.
I also take an exhaust baffle that I can pack with wire wool for the static noise test which always does the trick - I've never had to use this on track though as 911's are mostly worse on the static test than the drive/by.
Other options include a thick sound proof mat for the engine(just for the static test), use standard airbox to reduce intake noise, a tach cheat(switch able tach from 6 cylinder to 8 cylinder), lie about the redline(its mapped for tq not bhp) and finally...
..make sure you slowly raise the revs to below what they ask for then wait for them to ask you to increase it - ie dont start with a heavy blip up to 6k which WILL read very high.
Good luck ext time dude
Was the engine hot or cold/warm during the test? 5200 rpm isnt far off whats needed for 75% throtlle (6800*.75=5100) so in the right ballpark.
You can generally kill a few DB on the static test by getting it very hot with lots of low gear high rpm runs - saved the bacon of a few of our group at various UK trackdays.
I also take an exhaust baffle that I can pack with wire wool for the static noise test which always does the trick - I've never had to use this on track though as 911's are mostly worse on the static test than the drive/by.
Other options include a thick sound proof mat for the engine(just for the static test), use standard airbox to reduce intake noise, a tach cheat(switch able tach from 6 cylinder to 8 cylinder), lie about the redline(its mapped for tq not bhp) and finally...
..make sure you slowly raise the revs to below what they ask for then wait for them to ask you to increase it - ie dont start with a heavy blip up to 6k which WILL read very high.
Good luck ext time dude
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03-11-2012, 07:31 AM
#8
Don't know how effective this part is, but the principal is good http://www.design911.com/Exhaust-Tai...nTek/prod5504/
03-11-2012, 09:48 AM
#9
Going by my extensive experience of bike dB tests (lots of track days culminating in a brush with the grim reaper and no more bikes), almost every track is different, but advise given so far is good.
As dB measurement relies heavily on the calibration of the meter, the only way to be certain is visit the track first, but to get a reasonable idea plenty of mobiles either have a dB meter built in, or you can download an app for one. Whilst not industry standard, you will see what ball park you are in
Certainly with a bike, you can cut around 3dB's from the noise by having a hot engine and cold exhaust, not sure why this works, but it does.
John
As dB measurement relies heavily on the calibration of the meter, the only way to be certain is visit the track first, but to get a reasonable idea plenty of mobiles either have a dB meter built in, or you can download an app for one. Whilst not industry standard, you will see what ball park you are in
Certainly with a bike, you can cut around 3dB's from the noise by having a hot engine and cold exhaust, not sure why this works, but it does.
John
03-11-2012, 09:51 AM
#10
Don't know how effective this part is, but the principal is good http://www.design911.com/Exhaust-Tai...nTek/prod5504/
John
