riaansh
Expert Class
Posts: 195
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posted January 20, 2008 10:17 AM
Question or two
Both zx 14's
How much in bike lengths is a quick shifter worth on a sprint?
How much will you loose if you are 25kg heavier than the guy with the quick shifter also.
Will a 16 front and back 40 do ok on a 1km sprint or will you loose to much top speed?
  
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lietoome
Needs a job
Posts: 2033
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posted January 21, 2008 09:42 AM
need more info. your weight, his. Roll ons? Not sure what you mean by Sprint? Why 16/40? 16/40 is an odd combination, I'd try a 16/42 or 43... I run 17/45. Other mods, or just one with an airshifter? 1 mile=1.6km, not many people run (approximately) 1/2 mile. You may wanna talk to the guys that run the 9/10ths (Phantom, Ship...and others)
(From what I've read), the airshifter is good for about a 10th of a second in the 1/4 (0.4 km)mile...over a 1/4 you'll have deminishing returns because you're not shifting but one or two more times after the 1/4 mile mark.
If you can give as much info as possible, some of the guys that know WAY more than me will chime in.
L2m
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Halvefast
Zone Head
Posts: 806
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posted January 21, 2008 10:27 AM
Riaansh- L2M is right, gearing can be steeper, 16-40 I go thru the 1/4mi. in 4 gears. Probably would go with at least 16-41 maybe more, I have run a full mile with this gearing into 10-15mph winds.
2nd a quickshifter or airshifter won't shave off alot of time, depending on how you shift the bike now.
Biggest differences will be weight and rider ablities.
More info will help!
____________
Texas Mile 200.256mph - Oct. 2007 (Update 202.577mph Oct 2008) NOS assisted
ECTA Ohio Mile 195.132mph
TexasMile 2012 199.9 mph all motor!
Streetriders Shootout 2008 series Pro/ET Champ!
Streetriders Shootout 2007 Series Pro/ET Runner-up!
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Bently
Needs a life
2012 14r In Blue and no Mods!
Posts: 5428
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posted January 21, 2008 12:59 PM
My quick shifter really did not lower my et at all in the 1/4. Guys that pick up a tenth or more from an air shifter are just not fast at shifting. I would say your disadvantage will be your weight difference. i know from experience if I was 150 to 160 I would have some pretty good numbers as well. I installed an airshifter for this year just so I can leave my weight on the tank untll I get in second gear.
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riaansh
Expert Class
Posts: 195
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posted January 21, 2008 01:23 PM
Sorry for being so vague guys, and thanks for the reply's.
Challenge from another zx 14 guy.
My mods is: Brocks street meg and race map. standard gearing.
His mods: Akra exhaust. Dyno run map. Quickshifter. Gearing I'm not sure of. O, he is at least 30kg lighter than me. Top drag racer in the area.
Road - +- 2 miles long. Slight uphill towards the end of the run. 10 mph wind from the side on the day.
He pulled me about 8 bike lengs from a 2nd gear roll on. I managed to close the gap towards the end of the run, but not by much.
Now, will the 16/40 gearing be ok for this run. Will I be able to close the gap with this gearing and maybe get a closer run towards the end of the road? I don't want to be to radical with the gearing for the top speed run.
Some more info and thoughts will be appreciated. I will be happy to have a closer run on the next event and I realize I wont win. Some of the guys speculate that he had some more mods done.
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kimski2001
Expert Class
Posts: 144
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posted January 21, 2008 03:58 PM
i would go @ least 1 down,my gearing is -1 and +1 and my top end is still killer.i've never tried it for 2 miles maybe a mile tops.thats a long way to travel on a top speed run!i have a 14 with a smeg flies out track map strapped lowererd ceramic wheel bearings air shifter bmc filter accelerator pump feature(i think this actually works)40 rpms 90% throttle and no added fuel to the map pair mod stretched 5 inches.i love the air shifter(no missed gears) im a good shifter but we all miss gears!not sure how much in lbs,30 kg's is,but amytime you have a lighter rider with basiaclly the same equipment the results will usually go their way unless he makes mistakes.also try some u4 it'll help,good luck.if that dont work find a light weight jockey and put him on it!
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1st14injax
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BlackMagic14
Needs a job
Posts: 2058
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posted January 21, 2008 06:53 PM
He is going to out accelerate you being lighter and not to mention since he is an experienced drag racer and smaller he is probably in a better TUCK then you and is not as broad so he has less wind resistance. In a 2 mile run these will be huge factors!! A good way to check this is set your gauge computer to instant gas mileage and try different tuck techniques and see how it effects the gas mileage on your practice runs. the metter MPG you get over the 2 miles the more aerodynamic you are all things else equal. Just a little trick I learned from some Land speed guys to help you work on your tuck. and also find you want to be at the peak power for as long as possible. I would think -1 on the front and the stock rear should be close. Is this a roll on or a dead stop?
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Halvefast
Zone Head
Posts: 806
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posted January 21, 2008 06:58 PM
Nitrous!!!
____________
Texas Mile 200.256mph - Oct. 2007 (Update 202.577mph Oct 2008) NOS assisted
ECTA Ohio Mile 195.132mph
TexasMile 2012 199.9 mph all motor!
Streetriders Shootout 2008 series Pro/ET Champ!
Streetriders Shootout 2007 Series Pro/ET Runner-up!
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ninja12
Needs a job
Posts: 3310
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posted January 21, 2008 08:40 PM
30kg = 66 lbs
It's going to be very hard to get around him with equal power and a good rider.
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lietoome
Needs a job
Posts: 2033
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posted January 22, 2008 12:39 AM
quote:
Guys that pick up a tenth or more from an air shifter are just not fast at shifting.
..this is the class that I'm in...my foot shifts are HORRIBLE.
66 lbs is a huge disadvantage on similar bikes...especially if he's skilled in the art.
NOS +1
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riaansh
Expert Class
Posts: 195
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posted January 23, 2008 11:44 AM
 Edited By: riaansh on 23 Jan 2008 11:50
Sorry only got to the reply's tonight.
Is this a roll on or a dead stop? - Roll on black magic. I will take the advice of the gas mileage.
Well I got the 16 t front sprocket today, but unfortunately I cant get the @#%& sprocket nut off. Waiting for a power tool and a better quality socket.
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lietoome
Needs a job
Posts: 2033
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posted January 23, 2008 11:59 PM
riaansh, there are several threads about that sprocket nut removal. very good advice.
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