Slip on db question

[exint2]

Hi just got a Gen 4 and looking to do a few trackdays next year - would fitting one of the stubby end cans ( keeping the cats) mean it would fail some of the quieter circuits db levels - realise it's slightly vague question but looking for a general steer on the issue

 

[MrSmooth]

Given that you are keeping the Cats, and not trying to sound patronising here, wouldn't it be best to look up any proposed track days you might attend if they are published, or even the circuits you want to attend - the noise restriction levels will be published for the circuit on the circuit website, or a phone call would get you the info.

Then armed with that, go shopping for the slip on can, they mostly publish the dB output, and get one that you like and suits the noise restrictions and get one with a removable dB killer insert - just in case.

You can always take the stock exhaust with you if you are towing the bike or taking it in a van, that will definitely pass noise restrictions. I can change my SC Project slip on for the stock exhaust in about 15 minutes. The ECU will cater for the change of slip-on automatically I am told.

 

[bananaman]

I run a stubby, never been pulled on track. Doesn't make much difference at all with cat still on, just the overrun burble little more pronounced.

 

[Mellorp23]

The stubby Austin system on my old HP4 was too loud all the time (no cat) but did look great. Just about scraped through at Cadwell at 105 ish dB. The Akrapovi? slip on can on my Gen3 is fruity without being obtrusive. Still within the 98dB at Oulton. I don't think it would pass at Castle Combe due to the different noise test method (tested at 75% of the red line revs). Bedford has some odd drive by sound meters. Donington, Silverstone, Snetterton, Anglesey, Cadwell, Croft, Pembrey shouldn't prove to be a problem for noise. Don't know about Brands, Knockhill or Lydden

 

[Ste M]

I have a austin racing end can on mine and no issues at all, ive ran oulton and anglesey. I was speaking to Phil Crowe the other day and he fits full decat arrows that will also pass all the track noise tests no problem. thats my aim for the end of next year

 

[mattals]

I run full Akra Titanium system on gen 4 and goes through noise test with no baffle with no issues...Blows around 99db

I had a Full Arrow system on Gen 3 and wouldnt go through full stop...Got told it would be fine when i bought it. After advice from HM racing fitted the BMW supplied Akra Can on to the Arrow headers and then went through fine with no baffle. Did over 20 track days on that bike and never failed.

 

[oldwobbler]

The gen 4 is a quiet bike, my stock can is stamped 94db. Changing the end can only should still leave it below 98db which is road bike legal. I've got a slip on only and its very slightly louder, especially cold. As Mr Smooth says, take the stock can jic.