Weight reduction to HP gain?

[cnickk]

is there any formula or general relation to weight and horsepower? for example if i take out 100lbs will i gain 2.4 HP? If so does it matter where you loose the weight in the vehical? i know this is a broad question, but i need as detailed an explanation as possible.

[Q45tech]

You mean to say IF I remove 100 pounds what will the acceleration gain be -------with the same engine!

Depends on where you remove the weight and if rotating [wheels, rotors, flywheels, TC, gears, shafts or tires] or non rotating body weight.

Or what will be the acceleration improvement if the driver or passengers lose 100 pounds of weight.

4300/4200= 2.38% should improve quarter mile acceleration by ~~0.1 seconds.Pretty difficult to find 100 pounds to remove except in drivers as the engine/transmission/driveshaft/diff are fixed........AC system.

The largest variance is the 22.5 x 6.4 pounds/gal = 144 pounds a full gas tank makes........0.15 secs in quarter mile. Add up coolant, oil, ps, ATF, diff, brake fluid, AC charge, washer fluid ~~ 60 pounds or ~~200 pounds of liquids.

Rotating weight reduction is roughly 3X as good as static weight, depends on the diameter of rotating component. Wheels and tires being better than a driveshaft. Obviously a oem 15" tirewheel is much better than a 17 or 20" combo since they are always heavier.

The lighter [15 pounds 4x4] forged 15" wheels found on Q45t of 1991 just offset the weight addition [43 pounds] from HICAS......accelerationwise.

Almost every pound [of the 4300 loaded] is need to haul a 160 pound driver around in comfort.

[elwesso]

Best weight reduction can be had by getting lighter seats, if your up for that.....

[Jesda]

Drive past Krispy Kreme instead of driving through.

There's an old thread where some guy gutted his Q down to the bare nothings.

[cnickk]

i may just do that. nude j30t on the way. q45tech thankyou for your detailed post i understand now what has to be done.. your the man!

[maxnix]

i may just do that. nude j30t on the way. q45tech thankyou for your detailed post i understand now what has to be done.. your the man!

Actually, you will be better served by starting with a lighter car with the same engine, say a Z32 NA or TT.

Then you can continue to enjoy the J for what it was designed to do.

[cnickk]

i have a 1986 nissan pickup not the 86 1/2 but the 4 headlight style. lol i could mess with it . i dont have enough money to make my jcar faster and dont worry im not stripping her.she has been way too good to me.

[911/Q45]

I've always assumed 100lbs of non rotating weight reduction = 10 hp.

[Jesda]

I dont understand how you could gain power from less weight. You could gain acceleration I guess, as in Dennis' first post.

Oh yeah, try stickers!

[elwesso]

Hell NICO stickers are worth 15HP...

[DAEDALUS]

I've always assumed 100lbs of non rotating weight reduction = 10 hp.

I'd say that's not far off on average, but the Q is heavy. F = maChange in force is 1:1 for change in mass. Given the Q's weight, 100 lbs in acceleration ~ 7 ft-lbs at peak.

[Q45tech]

The old 100=10 rule of thumb was for cars that had a 10:1 HP to weight ratio obviously 4300lbs/280HP= 15.35:1 so the ~~0.07 secs per 100 pounds might be more in line with real world results.

[cnickk]

dude q45tech is smart as hell. is there anything about autos you dont know?

[Q45tech]

What happens when you have 7 years of engineering schools and 15 years of automotive study.........owning/working on Q for 15 years.

Everyone can do it. Spending lots of ebay money on test equipment helps.