No Dyno? No Problem

OB_Bob

Registered
Alot of you probably know this, but for those that don't--A trip to the drag strip can help evaluate your mods. or check your stock HP.

Just use this formula--

HP=(MPH/234)cubed X Weight

For example lets say that our Busa ran 139 mph in the quarter. Here is what the equation would look like

HP=(139/234) cubed--you know to the 3rd power X the weight (725lbs.) 550 lbs. for the Bus + a 175lb rider.

.20960 X 725 = 151.96 HP

Its not perfect and assumes you have some ability at the strip. Trap speed shows HP.

Bob
 
That's a VERY useful equation. Thanx guy.

Dyno test and have fun at the same time. OK!!
 
I'm confused!
In your above calculation, if we drop 100 lbs of weight from the bike or the rider we get 0.20960 x 625(instead of 725) the hp figure goes down to 131hp, assuming the trap speed was the same, is this correct! The reason i was confused is a friends dynoed, modified r1 has run 148 rwhp and 140mph thru the traps but using your calculations the hp would only be around 130.
 
If I were to weigh 175lbs., as in the example , and ran a 139 mph trap speed. Then you jumped on and weigh 100lbs. You sure better be through the traps at a higher speed. Otherwise, your a not a great rider or you lost HP.
So lets say you are a good rider but tiny (100lbs) some would call you a Jockey.
I would estimate you would go through the traps at 146 mph===0.24289076 X 625=151.8hp
Hope this helps.
The equation isn't perfect but if your weight stays the same it is effective in evaluating changes to your bike.
Bob
It is important to know the weight of the bike and you. I have a materials supply near me, (concrete, stone, etc.) they have an outside scale accurate within 5 lbs. I will drive the Bus on it today then subtract my weight and post it later. (incl. gas tank level)
Your Friends R1---stock R1's weigh 419lbs. DRY WEIGHT- probably about 450lbs wet with some fuel. So, if your friend weighs 175lbs 625lbs total is reasonable. (133.8hp with the equation)The stock HP of the R1 is 129-130 Rear wheel. Change the weight to make accurate. Unless he weighs 225+lbs ask for his dyno sheet showing 148HP. The other thing about the R1 with std. swing arm is you CAN NOT keep the front wheel down. This may also figure in here, not usable power at the strip.

[This message has been edited by Bob (edited 30 August 1999).]

[This message has been edited by Bob (edited 30 August 1999).]
 
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