Supersprint Racing BB Noise Test

[$w!ft]

Strange thing happened the other day.

I was at Castle Combe for a trackday and headed over to the noise test area.

Powertrain wise car is stock except for Supersprint lightweight racing backbox.

Trackday limit was at 100dB, I passed at 102.7 dB twice.


I then drove my car on the road for 5 mins to warm up the pipes and just made it at 99.7 dB (phew! )

In any case, what is worrying me is that last time I was on track about a month before with the same exhaust there was a 95db limit and I passed with flying colours at 93db....

How could I get such different readings?

[shimmy]

It can depend quite slot on how they take the Reading

it should be at 0.5m at 45degrees to the tailpipe at I think 3/4 to red line

lots of chance of error even excluding atmospherics

shimmy

Originally Posted by $w!ft

Strange thing happened the other day.

I was at Castle Combe for a trackday and headed over to the noise test area.

Powertrain wise car is stock except for Supersprint lightweight racing backbox.

Trackday limit was at 100dB, I passed at 102.7 dB twice.


I then drove my car on the road for 5 mins to warm up the pipes and just made it at 99.7 dB (phew! )

In any case, what is worrying me is that last time I was on track about a month before with the same exhaust there was a 95db limit and I passed with flying colours at 93db....

How could I get such different readings?

[shane@mbtech]

Originally Posted by shimmy

It can depend quite slot on how they take the Reading

it should be at 0.5m at 45degrees to the tailpipe at I think 3/4 to red line

lots of chance of error even excluding atmospherics

shimmy

And not forgetting that exhausts when used for a bit do tend to get a little bit noisier than when new.

And as shimmy stated, tests can be different from track to track, person to person.

The usual tester at oulton is an ok guy and the readings are usually lower if he does it.

One day one of the stewards was on noise testing duty, he was too close and exhaust measured higher, still passed.

It can depend on so many variables as shimmy says.

[glendog74]

I have the same exhaust as you and it generally makes 97dB at track noise checks.

It may be a tad more when i stick my newly acquired SS unresonated centre section on, however...!

[kpkpkp]

Heat is a huge factor - my pals F430 went from 109 to 101 after getting them nice and hot.

Kp

[$w!ft]

Alright I will remember to get it really hot next time!

[Thorney]

Get em hot, all exhaust are quieter when hot. Also the variables in noise testing from these machines are quite wide.