Converting HMF

[FLIPSTICK]

Sent Utility Series back to HMF today to get it converted to a GS1 Ecosystem .

Just too loud for my liking.

[FLIPSTICK]

Exhaust showed up Monday , will post results for difference in sound this weekend .

[MuddnMason]

It was still to loud even with the quiet core? How much power loss are you expecting now, if any?

[FLIPSTICK]

Too loud for my liking .

the power gains of the eco are about half the gains of the utility.

Quote from HMF Forum

[TechForeman]

Might sound like a stupid question but how much louder is utility series over stock?

[FLIPSTICK]

HMF Utility series are around 104-105 decibels without quiet core and (HMF claims )
97 decibels with quiet core installed.

[1badrancher]

does it take 180 decibels to make you go deaf or is it 80 decibels??

[FLIPSTICK]

If a sound reaches 85 dB or stronger, it can cause permanent damage to your hearing.
With extended exposure, noises that reach a decibel level of 85 can cause permanent damage to the hair cells in the inner ear, leading to hearing loss

Decibel Exposure Time Guidelines

Accepted standards for recommended permissible exposure time for continuous time weighted average noise, according to NIOSH and CDC, 2002. For every 3 dBs over 85dB, the permissible exposure time before possible damage can occur is cut in half.

Continuous dB / Permissible Exposure Time

85 db / 8 hours

88 dB / 4 hours

91 db / 2 hours

94 db / 1 hour

97 db / 30 minutes

100 db / 15 minutes

103 db / 7.5 minutes

106 dB / 3.75 min (< 4min)

109 dB / 1.875 min (< 2min)

112 dB / .9375 min (~1 min)

115 dB / .46875 min (~30 sec)

[TechForeman]

dang, are those the stats for an enclosed room or just thats what it is for anything? that would suck if you could only ride for less than 5 min b4 you hearing starts screwing up.

[Jake]

Closed rooms are irrelevent. Decibels are the actual amount of energy that hits your ear. When you measure a pipe, it's at a given distance and angle from the outlet. Further away is less decibels. Closer is more. In a closed space, you don't have so much reduction by getting further away.
When they figured out how far and what angle to measure an ATV at, it very much approximates what the rider hears, so you can relatively accurately use the number they give when compared to a tolerance chart. Also remember that that will be at a certain RPM and stationary. When you put the engine under a load, wound up good, and wide open, you'll be well above any rated levels.

[TechForeman]

well does anyone know what the decibel rating is on a stock exhaust?

[Jake]

87 comes to mind, but I'm not positive. I might be smoking opium too. You never know.

[MuddnMason]

You better lay off the opium......... not good for you.