0din

Is there a formula to estimate the amount of horsepower needed to balance out the effect of added weight?

For example, I plan on adding Roadkill sound deadening material on the entire inside of the doors, floor, rear quarters and trunk of my '08 GT. I figure that this will add at least 50-75 lbs evenly distributed throughout the car.

I also plan on adding a subwoofer to the right rear corner of the trunk (JL Audio Stealthbox) and 2 amps under the rear deck. This equipment, with added wiring and misc, will probably add close to another 50-75 lbs.

Many suspension and performance parts (not counting power adders, which make up for their weight) add weight (sway bars, strut braces, wider tires, etc...).

Also appearance mods (of which I don't plan on doing many, if any) like body kits, hoods, wheels and tires, etc. add lots of weight.

It's not unusual to imagine adding several hundred pounds of weight to a car with the various mods. I constantly see people reference other cars as being "heavy" when they weigh a few hundred pounds more than a S197, and I see references to other cars being "light" wehn they only weigh a few hundred pounds less than a S197.

So what's the horsepower to pound ratio? For example, if you add 100 lbs to your car how many HP do you need to add to get back to the same 1/4 mile performance that you were before that 100 lbs was added?

howarmat

100lbs = 10 hp = .1 et

give or take a little

0din

2006 Pontiac GTO LS2 auto
400 BHP
3725 curb weight


2006 Chevrolet Corvette LS2 auto
400 BHP
3179 curb weight


2006 Ford Mustang GT auto
300 BHP
3525 curb weight


The Mustang is 200 lbs less weight but 100 HP less power than the GTO, so the GTO should be 0.8 seconds faster in the 1/4 mile.

The Corvette is 346 lbs less weight and 100 HP more than the Mustang, so the Corvette should be 1.346 seconds faster in the 1/4 mile.


Are these 1/4 mile time differencesabout accurate, considering all auto transmission cars/same driver/same conditions/bone stock cars?