track day noise testing

[teabagger]

Hi all,

I recently attended a Cadwell park track day where I noticed the noise testers were measuring the noise from the exhaust by holding the tester up against the tail pipe. I have read that these measurements are normaly taken 1/2 a meter and at 45 degrees from the tail pipe.

Why the different methods of measuring the same thing?
We scraped through at 103 db on a 105 db day

[sniff diesel]

The noise meter is actually taped to a peice of rod 1/2 metre long to keep the microphone the right distance away.

[teabagger]

sniff diesel said:

The noise meter is actually taped to a peice of rod 1/2 metre long to keep the microphone the right distance away.

Arh..

I thought the mic was on the end of the rod nearest the exhaust!

Thanks for clearing that up for me.

I have never taken too much interest in the noise tests as my car and bikes have been standard in that respect.
Now I am in the kit car world, I fear I may start to have run in's with the noise police more frequently.

[GTWayne]

teabagger said:

We scraped through at 103 db on a 105 db day

You were well in there
An increase of X 3db's is = to doubling your noise output, now THAT'S what you call

[s.m.h.]

The noise testing guys took one look at my CRX exhaust at Brands on Thursday, laughed and put a sticker on the window! Said I wouldnt offend anyone with that! TBH I think the intake made more noise at 8000rpm!

[raceboy]

Had to laugh at Bedford recently I left the TVR at home as a DIY test had that hitting 102Db at idle never mind the reading of 130Db at 4000rpm
The noise tester asked me to turn the BMW on, it is said I. Don't think this is going to have any problems passing then

[Jubal]

teabagger said:

Hi all,

I recently attended a Cadwell park track day where I noticed the noise testers were measuring the noise from the exhaust by holding the tester up against the tail pipe. I have read that these measurements are normaly taken 1/2 a meter and at 45 degrees from the tail pipe.

Why the different methods of measuring the same thing?
We scraped through at 103 db on a 105 db day

I never managed to get my old R1 car below 103db, except one day at Cadwell when they asked if it was a bike engine and tested it at 50% revs like a bike. Which was nice. I'm sure I could've tried harder to make it quiet but I just decided I'd do 105db days only...

[teabagger]

Jubal said:

teabagger said:

Hi all,

I recently attended a Cadwell park track day where I noticed the noise testers were measuring the noise from the exhaust by holding the tester up against the tail pipe. I have read that these measurements are normaly taken 1/2 a meter and at 45 degrees from the tail pipe.

Why the different methods of measuring the same thing?
We scraped through at 103 db on a 105 db day

I never managed to get my old R1 car below 103db, except one day at Cadwell when they asked if it was a bike engine and tested it at 50% revs like a bike. Which was nice. I'm sure I could've tried harder to make it quiet but I just decided I'd do 105db days only...

We have a slight blow from the back of the silencer which will require repacking but I'am not sure how much this will help.

Are there any reasonably priced noise meters on the market so we can run some tests at home?

[GTWayne]

Maplins do a couple of low cost meters

[teabagger]

GTWayne said:

Maplins do a couple of low cost meters

At £14.99 I may invest in one.
Thanks.