Track Day dB Reduction Ideas

[RGG]

I've just posted a similar question on the bikers section.

A TVR guy has responded so I thought I'd ask you guys as well.

I need to find a way of getting my dB level down just for track days.

I need to try and get the dB level lower than 103.

The silencer boxes have plenty of space for packing.

My question is -

Can I / should I pack firmly to the maximum possible and if I do will maximum density result in a lower dB level?

Or are there any other ways to get the noise level down?

[RichB]

Are your exhaust tail pipes the wrong shape for track day cans? (Additional silencers that push onto the tail pipe.)

[RGG]

RichB said:

Are your exhaust tail pipes the wrong shape for track day cans? (Additional silencers that push onto the tail pipe.)

They might be possible.

The potential problem (to be solved) is the tailpipes exit through the rear clip but hardly at all. - Millimeters.
So, the rear clip has to be down before the add ons are connected.
Not impossible, nothing is but at the moment it looks like a headache.

Don't know if any of that makes sense.

[andrewcliffe]

When we were running F3 cars, we used repackable silencer boxes and a certain length of Acousta-fil woven packing. It lasted much better than traditional silencer wadding. There are also additional silencers which could probably be made to fit (possibly pointing down)

[RGG]

andrewcliffe said:

When we were running F3 cars, we used repackable silencer boxes and a certain length of Acousta-fil woven packing. It lasted much better than traditional silencer wadding. There are also additional silencers which could probably be made to fit (possibly pointing down)

Thanks for the Acousta-fil brand .
I'll look at that.
And the extension pipes pointing down, a few have now been suggesting that as a solution.

[andrewcliffe]

The noise rest regulations for competition cars (from Motorsport UK's NCRs)

"Measurements will be made at 0.5m from the end of the exhaust pipe with the microphone at an angle of 45° with the exhaust outlet and at a height of 0.5 to 1.0m above the ground."

if they're pointing down its harder to achive the 0.5m distance.

[Antoinne]

Don't forget the drive-by noise test too. Each circuit has microphones around the circuit which feed the data back to the circuit manager's office. The data has to be sent to the Local Authority, so if you pass the static test, but then are too noisy lapping the circuit, then you will be pulled into the pits.

[RGG]

andrewcliffe said:

The noise rest regulations for competition cars (from Motorsport UK's NCRs)

"Measurements will be made at 0.5m from the end of the exhaust pipe with the microphone at an angle of 45° with the exhaust outlet and at a height of 0.5 to 1.0m above the ground."

if they're pointing down its harder to achive the 0.5m distance.

Thanks -

It's Spa and for that day it looks like 107 dB static and 103
dB dynamic, so that makes things a bit better.

I'll be looking at the down pointing devices.

Edited by RGG on Tuesday 18th March 09:50

[RGG]

Antoinne said:

Don't forget the drive-by noise test too. Each circuit has microphones around the circuit which feed the data back to the circuit manager's office. The data has to be sent to the Local Authority, so if you pass the static test, but then are too noisy lapping the circuit, then you will be pulled into the pits.

Thanks Antoinne,

It's Spa, 107dB static and 103dB dynamic. on that day.

I think I've just discovered.