Failed Noise Test on Trackday

[damianc4s]

I was due to attend a trackday where a limit of 98db was placed on the cars. However when mine was tested it recorded the highest of the day (108.8db) much to my dismay!

This test was performed at 4500rpm, so just around the power 'sweet spot'!

I'm using the PSE without the bypass switch so I was expecting it to be loud but not that loud. So I'm wondering if the added effect of the Fabspeed Cold Air kit/BMC F1 really contributed to this.

Does anyone have any decibel readings of a normally aspirated 996 in various states of 'tune' as a benchmark.

Many thanks,

Damian

[Danyol]

Well done Damian, getting to rock concert levels!

How did they measure it; at what distance and orientation with the car, in the open or near any walls?

[damianc4s]

Thanks :)

They measured it at about 6ft in the open!

Damian

[JimB]

Wow, that's way louder than I would have expected. Are you sure they were measurings it properly? You should be under 98 my any method I've heard of tracks using. Usually from the side of the track near a high RPM point.

108 at 4500 seems crazy.

Edit: What track were you at? They wouldn't let my car in the same state if they won't let a stock car with PSE on the track.

Edited May 11, 2005 by JimB

[Loren]

Laguna Seca, Monterey, CA -- 92 dB @ 50 ft.

Infineon Raceway (Sears Point), Sonoma County, CA -- 103 dB @50 ft.

and someone told me Lime Rock, Lime Rock, CT is only 85 dB!

[damianc4s]

They are pretty strict at Castle Combe in Wiltshire having had many noise abatement orders served on them. All cars have to be checked prior to entering the track, several M3 and M3 CSLs all recorded 97db.

They do have meters around the track but everyone must pass the 6ft/4500rpm test.

[C4S Surgeon]

Yeah Lime Rock is actually 84dB this year. The airbox will make your car 10% louder, adds minimal hp, the bmc should have no effect. I run GHL quiet mufflers on mine, louder than staock, but not as bad as pse.