[insomniac]

Hello im a noob. Can you guys teach me how Weight makes a big difference in performance? For example i know that the exige is a really light car with only a Corolla engine and it has pretty kick ass performance. and its pretty common sense. but can anyone explain in depth? D:

*flame suit on for being a noob*

[Drow]

think about it this way:

you holding a bottle of water will run faster than the world's fastest runner carrying a fat chick on his back

[Jgresch]

Power to weight ratio.

[smk]

Power to weight ratio.

this

[FerrariEnzo]

For example i know that the exige is a really light car with only a Corolla engine

i think they have the Celica engine.. dont they?

[Rich Sandor]

It's not just about the power to weight ratio. If you have a 3500lbs car rolling down the highway, it takes a certain amount of force to make it stop, turn, or accellerate. If your car is only 2500lbs, it will be 'more willing' to change direction than a 3500lbs car. Lighter = more nimble in every way.

However, power is still very important, because weight does not affect your top speed - it only affects how quickly you get to the top speed. Aero, Horsepower, and Gearing are what determine your top speed. Those little lotuses are quick bastards around small and tight tracks, but a heavier car with significantly more power can be faster at the big long tracks!

[.Renn.Sport]

why don't you pay attention in physics class?

[nns]

why don't you pay attention in physics class?

Why don't you go die in a car fire?

[mb_]

^lol

[124Y]

A fat chick in your car may cause your car to gain 300lbs and scrape; all that work you've done to corner balance your car will also go to waste.
Now that's a difference.

[satek]

common sense dude.

[insomniac]

common sense dude.

:facepalm: thats what i wrote in the op

[flagella]

why don't you pay attention in physics class?

rofl I bet most of the people can't explain it in physics terms.

I don't even know what OP means by "explain in depth." Maybe ask a prof if you want all the formulas and theories.

Just keep it simple. Heavier cars move slower.

[Soundy]

It's not just about the power to weight ratio. If you have a 3500lbs car rolling down the highway, it takes a certain amount of force to make it stop, turn, or accellerate. If your car is only 2500lbs, it will be 'more willing' to change direction than a 3500lbs car. Lighter = more nimble in every way.

However, power is still very important, because weight does not affect your top speed - it only affects how quickly you get to the top speed. Aero, Horsepower, and Gearing are what determine your top speed. Those little lotuses are quick bastards around small and tight tracks, but a heavier car with significantly more power can be faster at the big long tracks!

Keeping in mind as well that this is "all else being equal". Heavy car with proper race tuned suspension = more nimble than light car with bagged-out stock shocks, and so forth.

Weight DISTRIBUTION matters to, somewhat to acceleration, but especially to handling. Within a certain range, 50/50 is optimal (meaning 50% of the weight is on the rear wheels, and 50% on the front). The further you go away from that, the more it affects handling.

But again, ALL ELSE BEING EQUAL, like Rich says, a lighter car will tend to accelerate and handle better than a heavier one.

In physics, it's all related to "intertia" and "conservation of momentum".

[woob]

As a car's weight increases, its inertia and the friction forces acting on it increase as well (friction force is defined as Fr = N*[mu], N = normal force, which is proportional to the car's mass) - this is an oversimplification since a car is on wheels, but for the purpose of this explanation it stands. The increased static friction and inertia make it harder to move from a stopped position. While the increase in friction may also lead one to believe that the car will stop faster, the simple fact is a car's wheels lower the dynamic friction in the direction of the car's movement and thus the car's inertia is the limiting factor of a car's stopping power (i.e. heavier car -> more inertia -> takes more force to stop). The increased inertia also means it takes more force to change the direction of a car when it is moving.

Inertia is defined as the tendency of a body to maintain its state of rest or uniform motion unless acted upon by an external force (http://www.wordnetweb.princeton.edu/perl/webwn).

Of course, this is an extreme oversimplification of how weight matters. As Soundy said, the distribution of weight will also affect the physics of a car's movement.

It's been a while since I've looked at dynamics. Let me know if I've messed up. I have a tendency to do so when it comes to any kind of applied mathematics. There's a reason I went into geology.

[Soundy]

^Pretty much got it. I think the friction is a little over-stated as it relates to the total weight - variation in tire compounds would make a bigger difference. For that matter, silly things like gimped-out camber (VIP, anyone?) reducing the contact patch would make a bigger difference :)

[dougthediggler]

http://en.wikipedia.org/wiki/Power_to_weight_ratio

took me 15 seconds to find... google / wiki is your friend son.

[optiblue]

It's funny that this was brought up! Basically for normal performance driving and cornering, lighter is better, but once you go faster it's actually more beneficial to have more weight / downforce for maximum stability.

[toyota86]

Lighter is usually better but not always the case.
Read up on Race Car Vehicle Dynamics by Bill and Doug Milliken

[busdriverman]

a heavier car will feel more stable at very high speeds

[Qmx323]

THE MORE AN OBJECT WEIGHS

THE MORE POWER/FORCE IS NEEDED TO PROPEL THAT OBJECT TO A CERTAIN SPEED

IE. A 300 HP 4000 LBS CAR MIGHT TAKE 6.7 SECONDS TO REACH 60MPH

IT WILL ONLY TAKE 3.35 SECONDS FOR A 300HP 2000 LBS CAR TO GET TO 60 MPH

Theoretically speaking of course, with all factors being controlled (tires, road condition, driver weight)

[shenmecar]

Lighter cars = better gas mileage. Thats a big difference at every gas station fill up!

[!SG]

i think they have the Celica engine.. dont they?

celica gts engine = corolla xrs engine. same 1.8 190hp.

[orange7]

physics 11/12

*edit.. nvm.. it should be more like common sense

[GabAlmighty]

Just put a tank engine in it.

[SpoonFit]

It's funny that this was brought up! Basically for normal performance driving and cornering, lighter is better, but once you go faster it's actually more beneficial to have more weight / downforce for maximum stability.

Like the new GT-ARRR

[PDA_86]

celica gts engine = corolla xrs engine. same 1.8 190hp.

The '05 Corolla XRS is a detuned version of the Celica GTS engine though. It only has about 170hp.

[hk20000]

Although it is sort of common sense Top Gear advises you NOT to randomly strip weight out of a modern production hot hatch because more likely than not you will put an adverse effect on its handling.

Stig drove the normal weight and the ghetto stripped twingos (about 150kg removed) around the top gear test track and they lapped it at exactly the same time. The reason being that being a hot hatch it was already well balanced from factory you really should not have touched it.

the golden rule is: if you want to go faster, buy a faster car.

[Mugen EvOlutioN]

The '05 Corolla XRS is a detuned version of the Celica GTS engine though. It only has about 170hp.

and GTS is actually 180hp

[XtC-604]

i think they have the Celica engine.. dont they?
it has a celica/corolla XRS engine/

[Grim]

and GTS is actually 180hp

in UK Sport-M edition is tuned for 190hp :D