noise testing

[clive f]

I could do with some pointers on how the sound tests are carried out at trackdays, I`m making some silencers to get the noise down and need to test them with the db meter, but at the right distance away from the pipes and also is the meter held directly facing the exhaust or at a 45 degree angle to it?

I understand the static test is tickover and 4000rpm?

[jagracer]

It's usually 1 metre and about 45 degrees, which way the pipe angles can make a big difference. They normally ask for 3/4 of max revs, dont forget that in some cases the noise can drop the more you rev after a certain level.

[wackojacko]

It depends, check yours at 45 degrees at 1M for a rough idea.


Castle Combe last month tested at 0.5M at 45 degrees at 4500 rpm to be under 100DB was tight as feck forsome !

[wildman0609]

in MSA blue it states 0.5m and 45deg to tail pipes, also mentions taking readings from both pipes if duel exit and taking highest reading. track days have to use same rules.

3/4 of redline also

[joshG]

At oulton my 911 was 104.9 db, at cadwell it was 99 db?? To me this says the noise test equipment they use is utter rubbish.

[PetrolHeadSeb]

Static testing is one thing, but be weary of drive by limits too.

A PHer friend fell foul of this in a DC2 Integra Type-R at Snetterton last month after passing the static test (albeit only just).

If anyone has any advice on preparing for drive by limit's I'd be very interested to know.

[gtdc]

wildman0609 said:

in MSA blue it states 0.5m and 45deg to tail pipes, also mentions taking readings from both pipes if duel exit and taking highest reading. track days have to use same rules.

3/4 of redline also

No they don't. Trackdays are run to whatever the circuit's planning permission says hence the variation in rev limits from circuit to circuit.

Melindi

[5potTurbo]

wackojacko said:

It depends, check yours at 45 degrees at 1M for a rough idea.


Castle Combe last month tested at 0.5M at 45 degrees at 4500 rpm to be under 100DB was tight as feck forsome !

My GSX-R 750 used to fail Castle Combe limits in the mid-90s, with the factory exhaust on it!
I would think they're probably stricter now than 15 years ago

[Matt_N]

5potTurbo said:

wackojacko said:

It depends, check yours at 45 degrees at 1M for a rough idea.


Castle Combe last month tested at 0.5M at 45 degrees at 4500 rpm to be under 100DB was tight as feck forsome !

My GSX-R 750 used to fail Castle Combe limits in the mid-90s, with the factory exhaust on it!
I would think they're probably stricter now than 15 years ago

Combe has been 100db for a few years now.

Bikes are listed as 105db at 1/2m from tailpipe at 3/4 max rpm on their site?

[clive f]

thanks for all of your input guys.

[LordGrover]

Jolly banter with the tester and the offer of a fag and/or beerage can help.

[clive f]

:wavey, hi m`lud hows it hangin dude!

[LordGrover]

Not so well as you Mr F. You all dandy as per?
Hope to see the Sag sometime soon.