Saturday, January 28, 2012

My 3-Horsepower Diet

This is not to say that I'm obese or anything, but... I'll confess, I can use to lose a few... but hey, who can't? ... right?  Statistics show that upwards of 30% of all Americans are overweight, if not outright obese.  So, with the whole New Years resolution thing staring down my hamburger I went against my better judgment and made one... Yeah, you got it... Even though a cliche, I vowed to drop some weight this year. 

Uggg!!  What have I done?! Gone are the chips and salsa, gone are the late night Oreos and milk, gone the ice cream with Hershey's chocolate sauce that I SWORE was necessary for my clinically relevant (yet, self diagnosed) calcium deficiency... no more snacking... all gone!  My sweet-tooth has definitely fallen on unrequited hard times!


This is all fine and good, but I was going to need some motivation and find it quick to keep me "on the wagon"... and fast!  I didn't really care that much if my jeans were to no longer cut off my circulation while driving, and so what it I were to actually see muscle definition where once there was nothing but bulging adipose beneath lose skin, so what it I no longer jiggled while I brushed my teeth, and so what if I lost the man boobs?... well, OK... losing the man boobs would be nice.  But what I needed, what I desperately needed was motivation.  POWERFUL motivation!  Something relevant to MY life.


And then it came to me... I once heard a statistic, although unproven and possibly nothing more than an urban legend, that suggested a weight drop of 7 lbs. in a motor vehicle would translate to the equivalent of an available horsepower increase of 1.  

Could this be true?  It certainly made some sense.  Reducing the payload of any moving vehicle HAD to improve performance - but by how much?  This concept was fully embraced by  the "bobber" movement of the '40s and '50s and the "cafe racers" of Britain during the same period.  Strip your bike, down tossing off as much unnecessary weight as possible, to improve performance. Sounds pretty straightforward.

Stripping my bike would have been an option for me if my Moto Guzzi V11 Sport  were not already stripped down, nearly naked.  Short of refinancing our home to free up enough discretionary cash to fund carbon fiber wheels, and other insanely expensive modifications.... it just wasn't going to happen.  So, the only viable storehouse of excessive mass was.... well, me!  But, could I shed sufficient mass to make a difference without having to shrink to the size of Michelle Kwan without her skates?


A little research was in order!   There is in fact a plethora of information on reducing rotational weight (i.e. flywheels, cranks, connecting rods, gears, etc. - essentially all rotating engine and transmissions parts) as a means of effectively improving engine and drive train output and efficiency.  And there is an equal amount of information on reducing unsprung weight, that is, everything beneath your suspension (wheels, tires, etc.) to improve handling.  But, surprisingly not so much on freeing up horsepower by shaving weight.  However, we know it's true!  Tracking power-to-weight ratios are huge in considering the performance of motor vehicles and since this is a rather simple principle, 

(Note:  Simple is in the brain of the beholder!!) there should be a rather straightforward formula not requiring the assistance of Sir Isaac Newton himself to figure it out!



After considerable research (nearly 15 minutes!!) at the undisputed repository of all knowledge (Wickipedia and assorted moto fora), I ran across the following post on a Ducati forum.


DISCLAIMER: The potentially flawed physics formulas to follow are not the responsibility of this fellow... blame it on the fora!


Since:  Force = mass x acceleration (F=ma) or:  a = F/m; and given that Force at the rear wheel is a linear function of  horsepower (Hp), rpm, gearing and rear wheel radius, and given that mass and weight are directly related.  Keeping constant acceleration,  then varying vehicle weight would require that:
F1/m1 = F2/m2.  

Substituting w for m and Hp for F you get:

Hp1/w1 = Hp2/w2 

and
Hp2 = (Hp1 x w2)/w1

 or

w2 = (Hp2 x w1)/Hp1

If you want to know the change in weight that would result in a horsepower change of 1
then:

delta w = w x [Hp1/(Hp1+1)] - w

My Moto Guzzi V11 Sport (stock) weighs in at 483 lb dry, (less ~20 lbs for modifications) add 58 lbs fuel and lubricants giving a total wet weight of 521.4 lb.  Factor in gear (boots gloves, jacket, helmet, riding pants) and me... +230 (I have some REALLY heavy gear!!), that brings total weight to 751.4 lb.

Horsepower on the V11 after mods (high compression pistons, PowerCommander, custom exhaust and K&N filters) comes in at an estimated 110 Hp.

Solving: w = 751.4 x (0.991) - 751.4 
w = -6.77
So, I need to shed 6.77 pounds to realize the equivalent on an 1 Hp increase in power. Not too unreasonable!
What you will find in this equation is that 6.77 is not a constant.  In fact with, lower initial weight and higher horsepower, the drop in weight to realize an effective gain in 1 Hp is considerably less than on a bike and rider combination weighing in at 751.4 lb!!

Consider Michelle Kwan (93 lb?) on a BMW s100RR (wet weight 451) and 193 Hp

w = 544 x (.995) - 544
w = -2.72

Given my current "state of the flesh", I think I can use to gain 3 Hp!! Now, THERE is motivation I can get behind!!  A genuine incentive that motivates me!!  

Whose counting pounds dropped when we can be contemplating an increase in available horsepower?

So, each time I see a Snickers bar, a bowl of peanut M&Ms, a sack of Oreos... (insert favorite guilty consumable pleasure here...  I'm going to remind myself with my new mantra...

All together now... say it with me all you horsepower-hungry lazy lard asses ...

"NOTHING TASTES AS GOOD AS ADDITIONAL HORSEPOWER FEELS!"

-LD









 

2 comments:

  1. Well, now we're all motivated! Notwithstanding the calculations (I have discovered, thanks to my son's homework, that I am incapable of fourth-grade math), I believe you.

    Now you might like to try my tip for an additional 5 mph: eat a Fireball while riding. It works!

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  2. Your efforts to loose weight are commendable. My approach is a bit different in that I use physical fitness as a counter balance to maintaining overall health. North of 40, I have found that a healthy diet and physical fitness is about as close to the fountain of youth as there is. At 69" and 175 lbs, I can run 3 miles in about 22 minutes. Not bad for an old man so to speak. Similar to riding a motorcycle, exercise can produce endorphins and put a little bounce in the step.

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