EXHAUST NOISE REDUCTION

[MATHEW]

Hi all
I attended Oulton Park today for a track day and it was a complete disaster, I know its my fault but the car would not pass the noise level of 105db as I have a bike engined car and only took the revs to 7500 rpm I hit 108db, any suggestions would be welcomed to get the noise level down to 100db. I know you can get mufflers etc any suggestion as to a good one. My car by the way is a Fisher Fury with an exhaust on the side.
MATHEW

[sniff petrol]

Lower your rev-limit? IIRC they only test at 3/4 max revs.

[MATHEW]

i tried that telling them it only went to 10,000rpm and at 7500 rpm it was 108db which is 3/4 rev limit. My car will rev to 12,000rpm so would have been well over.
MATHEW

[Jubal]

You should run an airbox and the biggest exhaust can you can find. Make sure (if it's repackable) that you have packed it well, not too loose, not too tight. You should easily get below 105db and I've recently seen cars down to 92db running the two bike exhaust cans.

Oulton have noise regs they cannot avoid and whereas a bike would be measured at about 5k revs the same engine in a car is at 75% max revs. Apparently it's to do with the agreement they've made with the council etc to measure different vehicles in different ways and run a certain number of days of each per year. You can't really buck the system as they know the score with bike engined cars. If you really struggle then go to Cadwell for a fix. They measure a BEC like a bike there. Mine was 89db

It's as well to sort this soon as you can because noise regs are only going one way...there are already venues with limits more strict than SVA.

[juansolo]

Couple of options: get an airbox and a much better exhaust. A way we've found to get a BEC much quieter is to run two cans (one into the other, not split). It might require some creativity to make it fit, but it dropped the noise from a Radical to around 93db read at 3/4 rpm!