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TD noise fail help ZX10R

bonesetter - 24/8/10 at 09:52 PM

Attended my first TD in the new Mac#1 at Donny tonight and after just half a dozen laps was black flagged for 101DB drive by fail which meant the end of my night's driving The limit is 98 so that meant 101 was twice as loud...??

Jonny has said I can come along for Thursday's session FOC, which is the final evening session this season.

So, I need to find ways of making the car quieter between now and then...

I was talking to a driver of an MK 'blade fitted with what looked like the identical exhaust can, he said he had been short shifting at 9K through fear of the noise police. His car sounded fairly loud, as did many of the others there...

Anyway, do I need to just need to find a different can, and if so can you point in the right direction.

Cheers

austin man - 24/8/10 at 09:55 PM

cant you fit a reducer in the end of the can, sometimes the induction roar is the problem as well. As said some just watch their revs at certain points where the noise police are sitting

YQUSTA - 24/8/10 at 10:24 PM

not cheap but I had around 5 db reduction

link

MikeRJ - 24/8/10 at 11:20 PM

quote:
Originally posted by bonesetter
The limit is 98 so that meant 101 was twice as loud...??

No, 10dB is a doubling of perceived loudness, not 3dB.

You simply need a bigger/more effective silencer. If you have a re-packable silencer then try repacking it, and make sure you put enough packing in - too much or too little will reduce the effectiveness.

Using the original bike silencer would be a good move for low noise...

Flamez - 25/8/10 at 05:49 AM

I had cat fitted as well as a custom air box from .Mac1 and got the noise down to 101.

You won't get it much lower I don't think.

Some tracks are more lenient than others and look for loud days.

snapper - 25/8/10 at 06:20 AM

quote:

You won't get it much lower I don't think.

You can get it as low as you want, bigger can, more baffles
An air box over the carbs
A quick fix is a baffle tube fitted in the connecting pipe before the can, Rally Design

RIE - 25/8/10 at 07:17 AM

If you've got a bike can, search ebay for 'db killer' - I've known of them knocking off about 7db in a static noise test (with a fair amount of exhaust wadding too, lol).

quote:
Originally posted by MikeRJ
No, 10dB is a doubling of perceived loudness, not 3dB.

No, he was right first time. From wiki: "A change in power ratio by a factor of 10 is a 10 dB change. A change in power ratio by a factor of two is approximately a 3 dB change."

Flamez - 25/8/10 at 07:19 AM

quote:
Originally posted by snapper

quote:

You won't get it much lower I don't think.

You can get it as low as you want, bigger can, more baffles
An air box over the carbs
A quick fix is a baffle tube fitted in the connecting pipe
before the can, Rally Design

But there is a limit of noise over performance, not much point in having a quiet bec that can't pull the skin off a rice pudding.

ReMan - 25/8/10 at 07:20 AM

I have one of these for when very quiet is needed.
Not been measured, but almost too quiet!
You just need a flange-slip on adaptor also ebayable
http://cgi.ebay.co.uk/Suzuki-Bandit-1200-Exhaust-Can-/130423580842?pt=UK_Motorcycle_Parts

snapper - 25/8/10 at 10:12 AM

If the exhaust is to loud then you need a much bigger, diameter and length, straight through exhaust this will absorb more noise energy but not stop the exhaust flow.
However you posted for a quick fix so decible insert is quick and cheap, engine may run richer and you will loose bhp

russbost - 25/8/10 at 10:42 AM

What snapper said is correct, I stock the Db killers, & have tried one in my exhaust & yes noticeably quieter, it will affect power but is a cheap quick fix.
I haven't got them on the website yet but can do them for Ł9.95 + Ł2.95 P & P if it's any help?

snapper - 25/8/10 at 12:09 PM

Lightning - 25/8/10 at 01:25 PM

These work

Merlin Motorsport

bonesetter - 25/8/10 at 01:26 PM

Thanks for the replies everyone

I'm not sure the dB killer will work with the silencer I have as that needs 210mm of straightish pipe after the can to work (I've been reliably informed by Russ - thanks)

Is there a muffler which can be fitted to the end of the pipe?

[img]http://flic.kr/p/8vhSMZ[/img]

[Edited on 25/8/10 by bonesetter]

Lightning - 25/8/10 at 01:29 PM

see above

bonesetter - 25/8/10 at 02:02 PM

Decided to go with a Db killer from Russ which he thinks will work, and if it doesn't I can fit fiberglass wool between it and the inside of the tail pipe...

Fingers crossed

progers - 25/8/10 at 02:37 PM

quote:
Originally posted by bonesetter
Decided to go with a Db killer from Russ which he thinks will work, and if it doesn't I can fit fiberglass wool between it and the inside of the tail pipe...

Fingers crossed

Not a good option IMHO. DB killers strangle your exhaust and reduce the power of your engine. In some cases it can cause incorrect fuelling resulting in engine damage in the long term. Don't forget you are dealing with a highly tuned BEC, not a lightly tuned boat anchor :-).

I personally would hate to be running full bore on a trackday knowing that a) you should be going faster and b) wondering how much damage you are doing to the engine. Db killers are just an emergency device to get you through a day if you have problems.

Its much, much better to bite the bullet and get a larger exhaust can - its the cost of one trackday. Also run with an airbox (if you haven't already got one).

My ZX12r engined racecar has no problems with noise at trackdays and pumps out its full quota of 180bhp. Its purely down to well designed 7" exhaust can.

As I said, just my opinion, but based one based on running BEcs for the last 7 years at various trackdays.

Paul

bonesetter - 25/8/10 at 03:15 PM

Agreed totally

I initially am after, and originally posted for, a quick fix for Thursday's evening session. I suppose I should have just gone for the larger can option straight away as that would have taken as long to arrive as the dB Killer...