Circuit noise limits, how quiet?

Andy916 · Post by **Andy916** » Sun Nov 18, 2007 9:36 am

I currently run a decat scoob that's relatively quiet, 94dB at Cadwell last week (0.5m, 45deg static).

Before I sell my standard backbox (that I never fit, it just sits in the workshop) lemme just check I'm not going to run into a problem at the quiet circuits...

Basic problem if a car's marginal on noise, is that some of the circuits quote drive-by at some indeterminate distance rather than static. So, it's difficult to check beforehand. For example:

Donington quiet-day: 98dB drive-by (static - no idea, and the circuit website is useless on this)
Bruntingthorpe: 87dB drive-by (equiv to 98dB static according to a quick surf of the web)
Bedford: 87dB drive-by (equiv to 101dB static according to a quick surf of the web)

(standard race limit is 105dB at 0.5m, 45deg static, and that's what Cadwell use for trackdays too)

So, I think my 94dB-static scoob should be ok everywhere (have I missed any?).
Or ... should I hang onto that quiet backbox just to be sure to be sure?!

Andy

duncan · Post by **duncan** » Sun Nov 18, 2007 10:14 am

What those drive by figures dont take into account is the additional noise that a turbo engine makes while on boost.

Do you take the spare back box to track days? If not - get rid

Post by **Stuart** » Sun Nov 18, 2007 11:21 am

Noise limits will get progressively quiter as time goes on so I would keep it. The

Gerry H · Post by **Gerry H** » Sun Nov 18, 2007 12:16 pm

The revolution system on mine is 93dB yet I was kicked out of Donnington for being over 100 on drive by and had to reduce the boost at Bedford to stay.

Shame as both are local to me.

Andy916 · Post by **Andy916** » Sun Nov 18, 2007 2:16 pm

dynamix wrote:Do you take the spare back box to track days? If not - get rid

No but I was keeping it with Bedford and Donington in mind, which I've not done in the scoob yet.

Donington I definitely want to do, so I think I'll keep it.

cheers
Andy

duncan · Post by **duncan** » Mon Nov 19, 2007 10:46 am

Can you get a restrictor bung for your system? It is a bit easier to carry around with you than a full back box assembly.

vpulsar · Post by **vpulsar** » Mon Nov 19, 2007 11:52 am

I'm just having a quieter 3" system made at the moment for a very good price indeed, And the quality of their work is top notch so if you're thinking of getting a new exhaust made up why not try AAS in Newcastle.

I'm hoping to be around 85-90 DB even quieter is pos, I just left them with the brief of making it as quiet as pos.

Simpson are very expensive in my opinion, It's only a bit of bloody stainless pipe FFS

.

Mine is getting done for