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Noise...I dont get it!
iiyama - 7/9/09 at 04:09 PM

Took the opportunity to get the car noise tested at Combe on Saturday. Limit was 100db(a)

Why do cars get tested at 4k rpm if they have a car engine and yet if there is a bike engine fitted they are tested at 3/4 redline? Dosent seem fair to be honest! Either test them all at 4k or test them all at 3/4 redline.

They were not doing drive by tests like they do at Goodwood for example and some of the cars were way louder then mine when on track. However my static noise was 102.3, (most of which I know to be induction noise).

Discuss.......

Flamez - 7/9/09 at 04:24 PM

so you wern't let on then I presume. There is no get out you just need to make the car quieter.

CC does have drive by testing though.

Tiger Super Six - 7/9/09 at 04:28 PM

But 4,000 is roughly 2/3rds of most car engines!

MikeRJ - 7/9/09 at 04:30 PM

quote:
Originally posted by iiyama
Took the opportunity to get the car noise tested at Combe on Saturday. Limit was 100db(a)

Why do cars get tested at 4k rpm if they have a car engine and yet if there is a bike engine fitted they are tested at 3/4 redline? Dosent seem fair to be honest! Either test them all at 4k or test them all at 3/4 redline.


It's 4500RPM for car engines at Combe, or at least it was in the very recent past.

The discrepancy does seem a bit odd, but a 3/4 rule for car engines wouldn't change things very much for most car engines e.g. with a 6500RPM red line, 3/4 would be 4875, not much different to 4500. The Honda VTEC owners must benefit a bit, but then again you'll get hauled in if they think it's too noisy on the track anyway.

blakep82 - 7/9/09 at 04:38 PM

is 3/4 maybe sort of approximate average racing engine speed?

iiyama - 7/9/09 at 04:52 PM

Definatly testing cars at 4k, most of the jap stuff will redline at 8-9k. Dunno about the Fords, pugs and other assorted chav mobiles!

Wasnt allowed on but to be honest I wouldnt have gone on anyway. Far to many idiots there on the day.

Also have to add that there wasnt any drive by testing that I could see.......

Jon Ison - 7/9/09 at 05:26 PM

cant beat a rev counter you can adjust, ie firing stroked per revolution.......

smart51 - 7/9/09 at 06:05 PM

I spoke to the noise guy at donnington. He said anything with a bike engine struggles as they are so loud compared with anything car engined. Power for power, a bike engine is louder than a car engine for the same power output.

I agree with you though. It should be 3/4 max engine speed for all engines. That said, bike boxes seem to have closer ratios than car boxes so perhaps their revs are proportionally closer to the red line than cars.

coozer - 7/9/09 at 07:58 PM

Scrap the noise test and have a visual silencer/not to loud common sense approach.

More PC for this crap country IMO.

will121 - 7/9/09 at 08:19 PM

not been to CC but every track day ive done always been at 3/4 of redline car or bike engined

zilspeed - 7/9/09 at 10:11 PM

quote:
Originally posted by smart51
I spoke to the noise guy at donnington. He said anything with a bike engine struggles as they are so loud compared with anything car engined. Power for power, a bike engine is louder than a car engine for the same power output.

I agree with you though. It should be 3/4 max engine speed for all engines. That said, bike boxes seem to have closer ratios than car boxes so perhaps their revs are proportionally closer to the red line than cars.



There's a bloke comes to our hillclimb. He has a Swindon Race Engines 2.2 Vauxhall XE.
I swear to God, the induction bark of this thing is ferociously loud. Way way louder than all of the bike engines.
There's also a bloke with a tuned KV6 which is similarly noisy.

Both of them in a good way, I have to say.
I understand the Xe is around 250bhp or so. The KV6 is over 300 and their induction systems are very unrestricted.

Genuine race tuned engines have an inductions bark that'll blow the gnat's fart of any bike engine right into the weeds.

carpmart - 8/9/09 at 05:47 AM

There is one solution which hasn't been suggested yet; fit a turbo and let that take care of the noise issue!