Data Tables

If you haven't noticed yet, I use a lot of physics and math to with my modifications and projects.  Usually I'll use a formula or derive one for whatever I am doing, but often it is easier for comprehension of something to view it in a data table than to read a formula.  Other times I record observations and data which have no formulas and all that ends up here on the data tables page.

Weight Loss to Horsepower to 1/4 mile time conversion (@ 2850 lbs)

 1/4 mile + - .1 s total hp + - 10 lbs lbs:s 20.5 s 1.23 hp / .1 s 85 hp 0.3 hp / 10 lbs 41 lbs = .1 s 19.5 s 1.51 hp / .1 s 98.76 hp 0.35 hp / 10 lbs 43.14 lbs = .1 s 18.5 s 1.85 hp / .1 s 115.65 hp 0.4 hp / 10 lbs 46.25 lbs = .1 s 17.5 s 2.31 hp / .1 s 136.63 hp 0.47 hp / 10 lbs 49.15 lbs = .1 s 16.5 s 2.92 hp / .1 s 163.61 hp 0.57 hp / 10 lbs 51.23 lbs = .1 s 15.5 s 3.75 hp / .1 s 196.64 hp 0.69 hp / 10 lbs 54.35 lbs = .1 s 14.5 s 4.9 hp / .1 s 240.2 hp 0.84 hp / 10 lbs 58.33 lbs = .1 s 13.5 s 6.52 hp / .1 s 297.63 hp 1.05 hp / 10 lbs 62.1 lbs = .1 s 12.5 s 8.86 hp / .1 s 374.93 hp 1.32 hp / 10 lbs 67.12 lbs = .1 s 11.5 s 12.34 hp / .1 s 481.48 hp 1.68 hp / 10 lbs 73.45 lbs = .1 s 10.5 s 17.74 hp / .1 s 632.57 hp 2.22 hp / 10 lbs 79.91 lbs = .1 s 9.5 s 26.41 hp / .1 s 854.09 hp 2.99 hp / 10 lbs 88.33 lbs = .1 s

The first column (1/4 mile)  is your 1/4 mile time in seconds, the second column (+ - .1 s) is how much horsepower is needed to increase (or decrease) 0.1 seconds off your 1/4 mile time.  The third column (total hp) is how much horsepower you would need to have to get the corresponding 1/4 mile time in that row (so to get a 15.5 second 1/4 mile with a 2850 lbs vehicle you will need about 197 horsepower).  The fourth column (+ - 10 lbs) is how many horsepower you will gain (or decrease if adding weight) for every 10 lbs of weight you remove (if I had a 200 hp car, and I removed 200 lbs, I'd look at the total hp column, see that at 200 hp every 10 lbs you remove nets you 0.69 hp, so I just gained 12.8 hp).  The fifth column (lbs:s) shows how many lbs you will have to loose to get 0.1 seconds faster on your 1/4 mile (using the same 200 hp car that I took 200 lbs off, that extra 12.8 hp would give me a 0.37 second faster 1/4 mile, because every 54.35 lbs takes off .1 seconds from my 1/4 mile).

The old adage is that if you remove 100 lbs from your car, you will run the 1/4 mile about 0.1 seconds faster, which corresponds to about 10 hp (100 lbs=10hp=0.1s).  This is an okay rule of thumb, but it is not that accurate, so the above data table is the exact calculations for removing weight from a 2850 lbs vehicle (the weight of my Shadow with a 200 lbs person in it).  The numbers work within 2% if you go all the way up to 3500 lbs or down to 2200 lbs, so this table is pretty accurate for determining horsepower and 1/4 mile time changes when removing weight.

Please note, I used the 'Approximate 1/4 mile equations' posted in the Formulas section, but I altered the ET equation.  I used 6.357 instead of the 5.5 as the weighted constant in the ET formula because I felt it reflects a more conservative scale for weight loss and 1/4 mile times.