Turbobike Web Site www.Turborick.com

Re: [turbobike] 1/4 mile gearing

Tue, 15 Jun 1999 12:50:13 -0400

The stock FJ topped out at about 149 mph, which is probably close to the gearing
limit for the stock 17/42 gearing, although the stock rev limiter settings do
vary quite a bit.  Don't even worry about the speedo reading since they lie so
badly.  Your 16/47 combo means that you only have 84% of whatever you started
with, which would be only 125 mph based on 149 mph.  You will run out of gearing
if you use your nitrous - maybe even without.  I geared my FJ 18/38 (the tallest
I can go with the stock wheel) which I really like on the street.  That gearing
gives me approximately 185mph @ 10,500 rpm, or 57 rpm/mph as indicated on the
rear wheel dyno.  Doing the math this way you would get about 133 mph @ 10,500
rpm with your gearing.  That would still appear to be a little shy for the kind
of power you're making on the juice.  Gear it taller and get into the nitrous in
2nd gear.  You'll never make up the E.T. in the 2nd half of the track, so you
need to be on the big power ASAP.


Jon Jarosz <jjarosz@camhydro.com> on 06/15/99 09:42:02 AM

To:   "'Turbobike Mailing List'" <turbobike@natvideo.com>
cc:    (bcc: Bob Shammas/CORP/Nsk-Corp)

Subject:  [turbobike] 1/4 mile gearing

I have a quick question for those who have more drag racing experience than
I.  I'm going out racing on Wednesday night, and it's been two years since
I was last out (motor go boom).  I've changed the gearing on my FJ to a
16-tooth front sprocket, and a 47-tooth rear.  The bike makes around 130
bhp on the dyno without the nitrous, and 200 with.  I've noticed, while out
ripping around, that the bike tops out at around 200 km/h.  Given speedo,
tach error, etc, that could be anywhere from 190 to 210, maybe 230 km/h, I
don't know - I'm not always looking down at the tach when I'm going that
fast down a country road or highway.

Nitrous notwithstanding, and given my lack of experience, will I run out of
motor before I go through the traps?  Anyone ever experienced this problem?
 This is something I never even thought of.

Thanks in advance,

Jonny Nitrous