To put shit into perspective. (Hp/weight ratio)

[Julien]

Dear R3v,
I'm sure most of us are in the later high school years or older. So this simple computation will be a breeze to follow and will help you in the effort to stop doing dumb shit to your car.

We all know weight is a car's natural enemy. We try to combat this by lowering our car's center of gravity, adding more sticky tires, more horsepower, etc. There is the other way of attacking this problem, which is of course, reducing our cars weight.

Now before you go remove your center caps, drain your windsheild washer reservoir and run on a 1/4 tank of gas all day read this consideration.

(I'm using 318is' numbers as they are the usual suspects).

Assumptions
Horsepower: roughly 136
Weight: roughly 2500
And most importantly... a difference of 5 horsepower can be noticed by most drivers (ie car has 5 more or less hp)

How does this translate into numbers?
[b]HP/Weight = coeffecient[b]
136/2500= 0.0544
(now, adding 5 horsepower)
141HP/2500Weight= 0.0564
(to find how much this translates to in weight)
136=0.0564x
x= 88.652lbs.

Next time you want to remove something from your car, think first about these numbers, than read up on air density and move to a colder country.

Over&Out,
Julien

[e30Matt]

So let me get this straight, adding 5 horsepower is as effective as removing 88 lbs from your car?

Well, looks like I've gained about 10hp on the good ol' 2.5 then. No more sound deadening material, interior, trunk tar, A/C (compressor, condensor, lines, evaporator soon), or heater core. :)

[Insanity]

Heh. Interesting calculations. However, you've failed to take some things into account...

1) The more horsepower you have, the more effective weight reduction is. Here, I'll show you using your numbers:

Say you have a 318 making 200 horsepower, instead of 135.
lb/hp = 12.5
Add 5 horsepower, and lb/hp = 12.2
12.2*our original 200 = 2440

This means that at 200 bhp, taking off 60 lbs is equivalent to adding 5 horsepower.

2) The heavier your car is, the LESS weight reduction helps (in terms of gained lb/horsepower).

Same example, but with a 3500lb weight:

base lb/hp = 17.5
205 lb/hp = 17.07
17.07*200 = 3414
3500-3414 = 85lbs

Counterintuitive, isn't it?

[Julien]

yup.. shows i study marketing. but still a good rule of thumb.

[Ryan Stewart]

Im lazy, I just added a shitload of HP. Math is for the asian kids. :P

[herragge]

Cool calculation, and in general probably very applicable. So basically, the weight savings every always tries to do is for the most part useless unless significant amounts can be removed.

Mike

[chuckybob]

best r3v post EVER.

im gonna go strip 500 lbs off my car and gain 28 hp!!!
















jk

[Garageaholic]

Yeah, but then you have to try to maintain the 50/50 weight dist. or you'll change the handling characteristics. We all know that its' easier to get rid of weight in the rear of the car (spare tire/housing- heavy ass trunk mats), but the handling of the car will change alot. There's only so much you can get rid of in the front. I just ran out of stuff to remove!! haha

[motorprestige]

Take into consideration that 50/50 weight distribution is not ideal, because any amount of acceleration will increase load on the rear while equally reducing load on the front, wich is where you need it when accelerating out of a turn. The e30 was engineered to be slightly front heavy, take into account the g forces of acceleration, and our cars acheive the perfect fifty fifty when we need it the most, when applying acclerative force out of a turn, or sometimes straight through one. Nissan has done the same thing with the 350z (z33), They have proven that 50/50 weight distribution under zero load results in a pushover effect while breaking, and a push under effect while accelerating, resulting in a chassis that is never cornering completely flat. There is constant fluctuation in the area of the tires contact with the road, wich causes an unpredictable, twitchy chassis.

[mikeedler]

wow, what ever happened to 500+hp pintos and crap. you all take this so far!
I feel like I am even stupider than i thought i was.
all i know is my car is fuh raze and its so fast since i dont have a spare tire or trunk tar in it! I KNOW that that added atlest 25hp!

[motorprestige]

wow, what ever happened to 500+hp pintos and crap. you all take this so far!
I feel like I am even stupider than i thought i was.
all i know is my car is fuh raze and its so fast since i dont have a spare tire or trunk tar in it! I KNOW that that added atlest 25hp!

^^ Just stop thinking and post more pics of your winter "beater". ;)

[Julien]

Words of wisdom:


Get a skinny girlfriend... or make a fat one pay for a chip.




Julien

[emmi]

its kinda hard to think of what to take out of the car... if you plan on driving it on the street... i was thinking of gutting the trunk but, that would just ruin the weight dist.