Could anyone one out there tell me the noise regulations at F1 outdoors in Massachusetts? I am running a stock Honda 125 shifter. I have heard its strict and was wondering what I need to run for pipe, silencer, and airbox? I heard the RLV 2 or 4 pipe with a 14″ moto silencer and an airbox would do and I have also heard other stories. Can someone who goes there please clarify? Thank you.
An airbox is required, (as opposed to the plain K&N style filter and nothing else). A 14-inch silencer should be enough to pass sound. That was my setup; R2 pipe with a 14″ RLV silencer and the 4-hole style airbox, and it passed. While the silencer and airbox matter, I don’t think the pipe itself, R2 or R4, makes much difference in terms of loudness.
And they will test for sound. Last time I raced there in 2013, they sectioned off a special area where they did a sound check. You had to pass the check and get the kart tagged (which was good for the season), before they even let you out on the track.
It is strictly enforced, set by the town the track is located in, and is beyond the control of F1 Outdoors to make any changes to it.
Actually now that I think of it, there may be one advantage to the RLV R2 pipe over the R4 when it comes to sound. The tip of the R2 exhaust is angled downward while the end of the R4 extends straight out. The exhaust pointed downward can help alleviate the DB readings when being tested.
No serious, top-level competitor runs the R2 in stock moto however. The R4 definitely has a peakier top-end than the R2, even though the R2 is more forgiving to drive. Some silencers have a curved or adjustable tip to them that you can move around to point the end tip straight down, (my silencer has a curved tip that can be pointed downwards, which helps greatly). The right silencer and an airbox (with the foam filter attached inside it), should be enough to pass the sound test, regardless of pipe used.
Awesome. I heard the R4 has a punchier top end. Ijust purchased the kart and it came with the R2so I will give that a try for now. Does the R2 make less power in general or just make the power in a different RPM range like the midrange? Thanks for the info with the sound. I have a 12″ RLV on there now so I prob will have to pick up a 14 to run at F1.
I believe that the R4 has a peakier top end, while the R2 has a broader (and more forgiving to drive) range, but not as high of a peak. I’ve never driven an R4 before; someone who has would have a better idea how the two match up.