bumcrack

What car I do to make the car lighter?
I've been looking at another bbs and the weight make's more difference than you might think.
If you drop 25kg's it's worth 5-7bhp( or something, I know it's a bit vague but it ages since I did my A levels).
If you look at the maths of it can make upto a few car lenths in 1/4 mile just by losing a few kg's
I still want the car to be practical, so the seats and the noise deading stay.
The spare wheel could go, and you can get lighter car batterys,not a full tank and drive about with no cloths on what else?

RussP

Rub all the paint off? It worked for Meredes...
Take all the windows out - it's summer after all.
Fill the tyres up with helium?

Hope that helps

Rus

JamieMacdonald

Go on a diet

RB5SCOTT

How much does a full tank of petrol weigh ? cos my car feels no slower when its full up than just before when its empty.

So i think to get any sufficient gains you would need to do the drastic things that you don't want to do unless you can get carbon fibre doors,boot,bonnet on the cheap

Scott

Floyd

iTrader: (9)

Lose the passenger at track days.

F

bumcrack

It would be interesting to get somebody who is good at the maths side in to this post, because it makes more difference than you might think. We are talking cars lenghts over 1/4 mile with just 25kg's.

The following inspired my post:-

Originally posted by Rick
need answer for power increase r/t wheel wt.
so if I dropped the weight of each wheel by 7.5 lbs with 16 inch volks with my stock tires how much hp did I displace or gain?
Now if I drop the weight of the rear rotors another 4 lbs each what increase will I realize?
--------------------------------------------------------------------------------



7.5 x 4 x 2.5 = 75-lbs x .0023 = .17 decrease
.17 / .023 = 7.5 hp

4 x 2 x 2.5 = 20-lbs x .0023 = .05 decrease
.05 / .023 = 2 hp.

Combined?
9.5 hp or .22 seconds worth of 1/4-mile decrease (nearly two car lengths) going with the Volks and lightweight rear rotors.
BTW, the Tanabe Racing Medalion weighs 13-lbs less than stock, so....
13-lbs x .0023 = .03
.03 / .023 = 1.3hp plus the 7-8hp gained from the exhaust itself. If you add these #'s together (1.3 + 7.5 = 8.8hp) and use my formula of 8.8 x .023, you get .2 seconds of performance help with the Tanabe. Because Taching9K's 19-inch combo probably weighs 30-35-lbs more than stock (total), figure the following:
30 x 2.5 = 75-lbs x .0023 = .18 seconds INCREASE in performance (over a 1/4-mile race).
The Tanabe decreased his time by .2 seconds and the tire/wheels increased it by .18. Could this explain why he feels the exhaust has more than made up for the larger tire/wheel combo? His results seem to verify my formulas, which as I said before, have freakishly been quite accurate in helping me to figure out what my mods will do (or won't do) prior to me getting a chance to go to the track or my personal "road course" used to chart performance changes. Also, for those who are really into putting their S2K's on a diet, just use whatever weight you can drop off the car and multiply that by .0023 so losing 50-lbs is akin to .1 seconds in the 1/4. As crazy as it seems, if you're looking for as much "edge" as possible when going for performance (er...drag/street racing, etc) have as little gas in the tank as possible. Since gas weighs 6.2-lbs per gallon, running with say, 3 gallons of gas in the car compared to a full tank is akin to having about 6-6.5 free horsepower. The entire time I had my Spyder, I don't think it ever saw a full tank unless I was going on a trip. I had it down to 2045-lbs with 155hp so my 1/4-mile times were in the 14.5 range. Now if I can just do something about my 6-4, 230-lb frame! You 5-7, 140-lb guys have it made!

What do you think?

EBR

hmmmmmmm I think I'm gonna have more fun in the muppet forum thanx