KTM Forums banner

1 - 8 of 8 Posts

·
Registered
Joined
·
475 Posts
Discussion Starter #1 (Edited)
Ok, odd question: Related to a track day im going to soon...they have pretty stringent noise restrictions (Its a track...so contrarian).

So to meet their guidelines, I thought of putting on something like an Arrow decat (that has the additional resonation), mounted to my stock muffler. I do NOT want to reinstall the Cat because of everything else going on with the bike.

Im trying to get this thing as quiet as I can.

For those of you who can answer yes to the post title...how is the sound? Is it still pretty quiet?

EDIT: found this - Does not seem like much difference between a stock can and Akra end can (by example) with using an Arrow Decat. Seems the "quiet" comes from the cat itself?
 

·
Registered
Joined
·
275 Posts
I'm using one with the stock can, it's still very loud when you rev it or get on it. I ran into a couple of guys in the canyons with full Akra systems and their bikes are definitely louder than mine with the stock can/decay pipe.
Most of the sound restriction is in the Cat
I have tried the cat only with the can removed and it sounds very good, not too loud but some growl.



Sent from my Pixel 2 XL using Tapatalk
 

·
Registered
Joined
·
863 Posts
Not sure if eur 4 matters but as Pablo said, don’t expect much spl reduction from changing slip on. Arrow has that 1/2 cat I know nothing about, perhaps its volume is something between the full cat and decat pipe. The stock pipe might make the inspector look the other wa?
 

·
Registered
Joined
·
234 Posts
96187


Decat + stock pipe was quiet enough to go on track with a year ago. There is a 95 dB noise limit here and it is measured at (if I remember right) three different locations throughout the track. Obviously the loudest your bike will be at the end of the main straight. Never had a problem. Remember that the sound the towers pick up (which is some hundred feet away from your exhaust, and depending on factors like wind direction) is most likely never going to give you any problems. If it's too loud, you'll be told before the trackday begins at technical inspection.

Expect a handful of additional decibels when you rip the cat off. The stock muffler does a good job. It's a nice throaty bark at speed, but not offensively loud.

Nonetheless, please doublecheck with regulations and your phone app and measurement methods to make sure your bike is good to go. If you don't pass inspection, say goodbye to your admission fee.
 

·
Registered
Joined
·
475 Posts
Discussion Starter #6
View attachment 96187

Decat + stock pipe was quiet enough to go on track with a year ago. There is a 95 dB noise limit here and it is measured at (if I remember right) three different locations throughout the track. Obviously the loudest your bike will be at the end of the main straight. Never had a problem. Remember that the sound the towers pick up (which is some hundred feet away from your exhaust, and depending on factors like wind direction) is most likely never going to give you any problems. If it's too loud, you'll be told before the trackday begins at technical inspection.

Expect a handful of additional decibels when you rip the cat off. The stock muffler does a good job. It's a nice throaty bark at speed, but not offensively loud.

Nonetheless, please doublecheck with regulations and your phone app and measurement methods to make sure your bike is good to go. If you don't pass inspection, say goodbye to your admission fee.
Good info thank you. I am going to Laguna Seca and they are claiming a limit of 90 dB :( - but ill still do what I can to help kill the noise
 

·
Registered
Joined
·
234 Posts
90dB. I wish I could give you more certainty on that. I think you'll be fine as is, as the sound that reaches the sensors is already weakened. But this sounds like a question you could run past the trackday organisers and your dealership too.
 

·
Registered
Joined
·
1,653 Posts
I have a MIVV decat with the stock muffler and it's pretty loud when you twist the wick but short-shifting allows me to sneak though populated areas and then open it up in the boonies. There is a universal db-killer available that slips in the front of the muffler, but until I encounter armed resistance (police). I'm going with it.
 
1 - 8 of 8 Posts
Top