How fast can a scooter really go? Dyno Data & Sprint Sim....

[drunkmunkey6969]

And.....kudos to you for your acknowledgment of DT. I agree. But....don't forget others, still waters run deep 2014 is going to be a 's**t or bust' year for a LOT of shops/crews/teams/people. But fair play to DT......he owned 2013. Nuff said.

[Wayne Miller]

Just read through this and also worked out the calculation for power versus drag and translated it into excel speak. It really is quite simple.

I translated it into this:

=SUM(BBHP*((RS/BS)*(RS/BS)*(RS/BS)))

OR

=SUM(G9*((E11/E9)*(E11/E9)*(E11/E9)))

Where:

G9 = Basis BHP
E9 = Basis Speed
RS = Required Speed

The cell with the sum will give you the required BHP

The calculation is only correct if all basis data remains the same and is the generally excepted equation (Its flawed by the way as it doesnt take into account rolling resistance)

So using the formula above and the data below you can work out that using a modern falc engine pumping out approx 30bhp (Lets say exactly 32.32bhp to be precise) on that day if all other base data remained the same then the scooter in question could have reached 155mph!!!!!

Think scootering did a feature on it recently and was approx 120mph in a cigar shaped body with only approx 15bhp from memory

This is where it f*cks my head up as obviously the above calculation is b@11@x

If a magic wand was waved and the scooter suddendly had 32.32bhp then this alone would not mean that the scooter would acheive 155mph. Obvioulsy the gearing would have to be altered for the new speed to be acheived and the pipe would require a redesign to allow the power to be moved further up the rev range to allow the scooter to hit the required speed. This in turn would have an affect of narrowing the powerband and therefore altering the characteristics of the engine and therefore failing this experiment as the base data has changed meaning that the outcome will not be as expected.

I dont get it, its now driving me mad!!!!!

Darrel what is the name of the software that your using. I need to buy it just so I can sleep tonight!

[Darrell Taylor]

the software is called Dynabike ,as far as im aware isnt commercially available and dont know too much about its history other than its author made it available to members of a tuning group im a member of , a good internet search may throw up a download location??

informative post from red devil there thanks for sharing!

2014 looks like its shaping up to be the year of sprinting as many machines are reaching completion ,think its time to start a new post "2014 Sprinting"

[vince]

Just came across this thread while looking for something on the tinternet . You cannot prove or disprove a timing card you can ask the organisers if they are happy the time is good . You can know what gearing you are pulling and what revs it was pulling and that tallys up with the result why should you not accept it. You turn upon any particular day and if everything falls into place you might just come out on top. But then there has always been more key board warriors out there than those actually prepared to spend there hard earned and get out there and give it a go !
For those intrested Sculthorpe top speeds were done on quarter gearing 18/46 LI 150 pulling 10000+ ish in top after a kilo run up , Elvington was a top speed event and with a mile ( 1.66 kilos ) to wind it up low down acceleration was of no concern but it was geared with a much higher ratio than Sculthorpe and had the kegra power system exhaust , it shortens 1.5 " in top gear to bring the power band up the rev range to give it extra revs and help spread the power over a wider range , that weekend a pacermaker box was used using 21/46 pulling in excess of 11000 for that short period before the timing lights, if you have the gear books work out the speeds !
For sprinting the bike is a legal sprint scooter , its very low it was narrowed 1.5" either side for this meeting to reduce drag , the front wheel covers are not fitted for Ford Sierra look like effect . The rider does not stick his head down behind the screen and look sideways near the end of the run because it looks cool its done for good effect.
The course had a slight down hill run at the end and the wind was strong pushing up the bike up its arse .

115/130/140 mph in the middle of a runway you tell me the speed because I dont know or can tell any better than you !

[vince]

I should of added that after the first fast run some adjustments were made and the second run was aborted as something was not right further tinkering resulted in a melted the piston on the third run . Wanting to still put in a back up run an over night trip to Essex to pick up another cylinder but this cylinder was from a group four and well down on power and would not pull the gears and the only way it would pull was with something like an 17/18 th sprocket and was well down on speed as well .