ok so everyones theory on 100 pounds = 1/10 in the quarter mile is just crap, i mean how could that be a standard amount, it would end up being a ratio of weight to horsepower anyways so it should be a certain percent instead. well yesterday i put it to the test....


all done on my beltronics FX2 http://www.beltronics.com/images/fx2.jpg man i love that thing...

i did about 20 full quarter mile runs out by my dads house, (the country) i ran consistent 13.8s at 101 all day in my NA form. i have about 5 runs with the same exact readings give or take +- .05 and .5 mph

then... i brought my 180 pound brother with me to see how much it would slow me down.....

did about 6 runs with him, high 14.2s and low 14.3s at 95.5 to 96.5 mph is the best i could do, i kept running and running to see if i could get better times, it just wouldnt happen. so that would mean that 180 pounds in my car slows it down 4 to 5 mph and 4/10ths of a second,

now i waited about an hour to do the runs with him in it to make sure heat wasnt an issue. so this shows that weight has more of an impact than you think. just think about why stock Gs have the same exact engine as the Z and run 3 to 4 tenths slower, cause of a 200 pounds +-

 

Well it depends where the weight is, does it add to the front or the rear weight distribution? .1 in the 1/4 is a good ball park for a typical vehicle, obviously it's not very accurate but it's a good place to start when considering weight removal/addition.

 

Exactly. Anytime weight is changed in he vehicle, you need to have the car corner balanced to fully benefit from weight reduction/additon.

 

100 pounds = 0.10 seconds is a rough guideline like 0.10 seconds = 1 car length. Very rough. Thanks for the tests and post. And along the same line is gasoline: running on a full vs quarter tank.

 

Yup, some folks forget gas weighs over 6 pounds per gallon, an 1/8 tank versus a full one can be 70+ pounds difference.

Just don't run too low as some cars the pickup in the tank will get exposed on a hard launch and you'll loose fuel pressure. I try to run between an 1/8 and 1/4 tank.