[A Atwood]

The SLP slip on muffler is advertised at 95.5 decibels @ 4200 rpm. But that doesn't tell me anything without knowing how it compares to a stock muffler? Does anyone have information on the decibel level of a stock exhaust set-up? Or any other aftermarket mufflers on an XP1K?

Thanks
ARN

 

[triton5150]

Around 84 stock

 

[A Atwood]

Around 84 stock

That must be idling. The SLP says 4200 rpm.

 

[A Atwood]

I have a decibel meter. Does anyone know how far away the meter is supposed to be held away from the muffler for the SAE test?

ARN

 

[OXPT18]

I have a decibel meter. Does anyone know how far away the meter is supposed to be held away from the muffler for the SAE test?

ARN

20” off to the side of the exhaust tip

 

[CyborgPirate]

The way the forest service tests it is 20” behind the exhaust tip and halfway to the ground from tip to ground. Directly behind the exhaust. Tested at idle and 5000 rpm

 

[OXPT18]

The way the forest service tests it is 20” behind the exhaust tip and halfway to the ground from tip to ground. Directly behind the exhaust. Tested at idle and 5000 rpm

florence Oregon, the tightest Reg anywhere @ 93db, they also go off to the side, especially if you have turn downs, 20” straight out and down would be in the direct flow of the exhaust! They also go by percentage of your redline, which they do not know often! I tell them 1000rpm lower than reality to help myself.
also notable, if you ignore them and avoid them, they never test you. That has been my method for 25 years, works perfect!

 

[CyborgPirate]

florence Oregon, the tightest Reg anywhere @ 93db, they also go off to the side, especially if you have turn downs, 20” straight out and down would be in the direct flow of the exhaust! They also go by percentage of your redline, which they do not know often! I tell them 1000rpm lower than reality to help myself.
also notable, if you ignore them and avoid them, they never test you. That has been my method for 25 years, works perfect!

Read my post again. It’s not directly behind the exhaust tip. It is halfway from tip to the ground. Turned down or not. This is how the regulations state on how the forest service is required to test them.

 

[Thestir]

Every sound check I have seen including Forestry uses SAE J1287 as the standard. It is level with the exhaust tip and 20in away to the rear at a 45 degree angle. Engine running at a steady RPM 1/2 of rated redline.

 

[OXPT18]

Read my post again. It’s not directly behind the exhaust tip. It is halfway from tip to the ground. Turned down or not. This is how the regulations state on how the forest service is required to test them.

Read mine again, that was how they tested mine, and every other vehicle I’ve seen tested, and this is by forest service, and local sheriffs, at the most restricted location for noise at 93db. Read what you want, but how they actually do it is not as your interpretation of the regulation.
the best way to pass, is to avoid the test, the cops, and forest service. I’m there to ride, not hang out with revenue hunting authorities!