Muffler bypasses, too loud for a trackday??

[FLAT-SIXY]

Hello all, im going to do the Brand's novice trackday in May, but ive got no idea how loud my car is with regards to decibels.
I think its 102 db's for evening, but im not going to put the muffler's back on just for the track day.
Ive heard louder stuff on the street, ie, TVR's, but has anyone out there got an idea what kind of noise my car is making. No other mods, just Fabspeed muffler bypass pipes.
I may need to find someone with an Iphone and a decibel reader app.
Cheers fellas.

 

[sailor]

Brands is one of the hardest noise enforcers. Can pretty well guarantee that you would fail with silencer bypass pipes.

JohnC
993turbo

 

[Mark Elder]

ORIGINAL: dongawoy

I may need to find someone with an Iphone and a decibel reader app.

My cheap digital multi-meter (from Maplin) has a decibel meter (no idea how accurate they are - although my limited experience of "sound men" at track days is they are not too accurate either!)

 

[FLAT-SIXY]

I ordered a decibel reader on ebay 2 days ago, should get it monday hopefully.
How far away from behind the exhaust and what rpm should the car be reving when noise testing? cheers.

 

[sailor]

ORIGINAL: dongawoy

I ordered a decibel reader on ebay 2 days ago, should get it monday hopefully.
How far away from behind the exhaust and what rpm should the car be reving when noise testing? cheers.

The tester holds the probe close (within a foot, normally) to an exhaust and will ask you to boot the revs to about 4500 ie about 3/4 revs. My beast reads about 102db, with a modded (S) engine, so yours would normally be 100 to 101, OK for most tracks. The beauty of a turbo is that it tends to muffle an exhaust - but not if you bypass ![]


JohnC
993turbo

 

[FLAT-SIXY]

I will read it when she's cold, "LOUD", and again when she's warm, not so loud. She will need to be warm anyway before I start hooning round some track, fingers crossed.[]

 

[T911UK]

I think you will struggle, those rear box bypass/tips are LOUD!!!

 

[FLAT-SIXY]

Oh well it was worth a try, my tester read between 105 and 109 dba, id better get my hands dirty and put the boxes back on if i wana do any track days.[]

 

[sailor]

ORIGINAL: dongawoy

Oh well it was worth a try, my tester read between 105 and 109 dba, id better get my hands dirty and put the boxes back on if i wana do any track days.[]

Sorry, old chap. Its the way things have gone in this nutty country we live in. My local track, Snetterton, is miles from anywhere, having been a bomber drome WW2. Been used for unrestricted motor racing since the 1940's, no problems. Then two years ago somebody located to a house a couple of miles away and started to kick up a fuss with Norfolk CC. Poor old Jonathan Palmer was put through the hoop, and had to design all kinds of raised banking - NOT just to improve the view for the public, but to mute the noise somewhat !
Madness.


JohnC
993turbo

 

[tscaptain]

ORIGINAL: dongawoy

How far away from behind the exhaust and what rpm should the car be reving when noise testing? cheers.

Most circuits test at 1/2 metre, at 45 degrees to the exhaust and at 4500 rpm. There are variations, i.e Castle Combe on a PCGB "noisy" day (105dB) will test at 1/2 metre, 45 degrees and 3/4 max rpm.

Some general info here
http://www.easytrack.co.uk/article/noise

 

[FLAT-SIXY]

Im still convined that my car is no louder than a Ferrari F430 when those vaves open in the exhaust. They must get track time.[8|]

 

[Melv]

ORIGINAL: tscaptain

ORIGINAL: dongawoy

How far away from behind the exhaust and what rpm should the car be reving when noise testing? cheers.

Most circuits test at 1/2 metre, at 45 degrees to the exhaust and at 4500 rpm.  There are variations, i.e Castle Combe on a PCGB "noisy" day (105dB) will test at 1/2 metre, 45 degrees and 3/4 max rpm.

Some general info here
http://www.easytrack.co.uk/article/noise

Thankyou Capt!! Saved me writing it out in full!! Some tracks are 3/4 metre from tailpipe

I do not consider Brands strict at all and have never been noise tested there!!!............Combe is prob the worst, with some flexibility from Goodwood, and I think Bedford are fairly tight

 

[tscaptain]

Of course there is a general "unfairness" here when testing rear engined cars given that the engine is also rather close to the meter. I have yet to see any allowance for that when noise testing. This test

The Two Metre Static Test
The meter is placed at 2 metres away from the centre of the car at a 90 degrees angle to the side of the car. The driver will be asked to rev the vehicle to 3/4s of it maximum engine revs.The reading will then be taken. This test usually only used if it is suspected that mechanical noise is giving a false reading. Rear engined car for example.

is available but has anyone ever asked for it?

 

[FLAT-SIXY]

I do not consider Brands strict at all and have never been noise tested there!!!............

[] I may be in luck!!! []