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sound db question???

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I have an 01' wr250 with an unplugged stock exhaust with vortip. I am considering a "quiet" pipe like the FMF Q or WB E2. Can anyone give me an idea how this might sound compared to what I'm running now?? Will these plug into my stock header? Thanks for the help.

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I have an 01' wr250 with an unplugged stock exhaust with vortip. I am considering a "quiet" pipe like the FMF Q or WB E2. Can anyone give me an idea how this might sound compared to what I'm running now?? Will these plug into my stock header? Thanks for the help.

i have the same bike, and an FMF Q. the FMF Q will bolt onto your stock header, or it can be paired up with an FMF PowerBomb header (which comes in two flavors, btw... the standard version and the SX version. the latter is designed to provide more low RPM power. i have the standard version on my WRF).

the FMF Q, in my opinion, offers the best balance of power and sound output. it is quieter than an open WRF pipe, quieter than a stock YZF pipe, and provides very nearly the same performance as the stock YZF pipe. my brother has a 2001 YZ250F, and in a side by side comparison they sound alike but the FMF Q tones down the raspy bark that the stock YZF exhaust exhibits. the FMF Q sound is still throaty and you definitely know it's a thumper, but it won't give you and everyone around you a headache.

with the FMF Q, i've had no problem passing 96dBA and 94dBA sound checks at various organized events -- the FMF Q is right at the limit. another benefit of the FMF Q over the stock WRF pipe is that it is markedly lighter than the stainless steel OEM unit. and of course the FMF Q has an integral spark arrestor and the requisite wording on the outside that says it meets the Forest Service requirements. all good when you are talking with the trail police.

see

http://losdos.dyndns.org:8080/public/riding/02aug2004-sixdays/IMG_1342_sm.jpg

note that in the picture it shows my stock header guard attached to the FMF PowerBomb header via a pair of Flatland Racing mounts. the FMF header, or at least the one that i have, does not have guard mounting bosses like the stock yamaha headers do.

ps

you can usually pick up an FMF Q by sniping in the TT "parts for sale" section. with a scratch or two, you can easily save a hundred bucks compared to buying new. and you just know that riding trails, esp rocky trails, you are just going to put more dings and scratches on it. so my advice is to buy a used FMF Q -- the worst that can happen is that you need to spend another $15 to $20 on FMF packing material.

jim aka the wrooster

'01 wr250f

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Here in MI sound is a BIG issue and getting bigger. I have the Vortip/stock can setup like you have and it has tested on numerous occasions at 89 dB(A), both by the MI DNR and by our state's rider group, the Cycle Conservation Club of MI

The FMF Q tests between 94-96 dB(A) depending on a number of factors including weather & the phsical features of the testing area. Every 3 dB increase the SPL (sound pressure level) DOUBLES which means the jump from 89 dB to 94 db you're quadrupling the noise.

The White Bros. E2 is available in a California 96dB version and in a FIM (Europe) 94 dB version which nobody has seen or is able to get. The difference is the length of the cans.

Here in MI we presently have a 94dB limit with a 1-2dB test window. The window will be shrinking if not eliminated.

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You are correct, I am mistaken :cry:

"The decibel scale is logarithmic meaning that a 10 decibel increase in sound pressure level is a doubling of the perceived sound pressure level ". So instead of the FMF "Q" being 4 times as loud it's not even twice as loud :cry:

So anybody got a used titanium "Q" for sale, cheap? :cry:

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you were right the first time.

3db increase of sound power is the effective doubling of the sound heard.

3 = 10 x LOG (sound1/sound2)

3 / 10 = LOG(sound1/sound2) = .3333

arclog(.3333) = sound1/sound2 =2

2 x sound2 = sound1

so sound1 is 2 times louder than sound2 when there is a 3db difference in sound power measured.

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The other option is the Yosh exhaust with the interchangable endcap and spark arrester. I have the same setup as Wrooster on my 02wr while my son runs the Yosh on his 02yzf. Both have passed inspection for trail events in Mich. However my son can change out the the spark arrester stuff in just a couple of minutes when we go to the track.

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