HP and Weight, this might be a little confusing Options

[celicarocker]

this whole theory is going off something i remember someone saying before. not sure of the exact numbers, but it was something like "every 125lbs you take out adds 4hp" or something like that. anyway, the point is there is a direct correlation between weight and HP.

now onto my main point. people talk stuff like "car A will beat car B becuase they both have the same HP, but car A is lighter" so if car B was reduced to the weight of car A, it would be faster? like if car A is 1900lbs and 150hp, and car B is 2700lbs and 150hp, wouldnt they both be the same speed? its like that old trick question "which would fall faster, a pound of bricks or a pound of feathers" where they'd both fall the same speed. so wouldnt a 1900lb car with 150hp go as fast as a 2700lb car with 150hp?

does anybody get what im trying to say?

[lagos]

think of it this way . most super bikes would smoke the hell out of any car on the road, yet they only make about the same hp as a stock celica does.

yes weight does matter a lot. many people do weight reduction mods, and they are a great idea, but the problem is that there is only so much that you would want or can strip out. you still have the weight of the chasis, the windows in the car and stuff like that, that you cant reduce.

[celicer]

there is a huge difference from somethign falling as apposed to somethign needed to be able to pull it.... like think you tring to pull its like think try pulling a beg of briks with ur hands and then try pulling a bag of feathers... which one will u be able to pull faster?

[CoSo]

this whole theory is going off something i remember someone saying before. not sure of the exact numbers, but it was something like "every 125lbs you take out adds 4hp" or something like that. anyway, the point is there is a direct correlation between weight and  HP.

now onto my main point. people talk stuff like "car A will beat car B becuase they both have the same HP, but car A is lighter" so if car B was reduced to the weight of car A, it would be faster? like if car A is 1900lbs and 150hp, and car B is 2700lbs and 150hp, wouldnt they both be the same speed? its like that old trick question "which would fall faster, a pound of bricks or a pound of feathers" where they'd both fall the same speed. so wouldnt a 1900lb car with 150hp go as fast as a 2700lb car with 150hp?

does anybody get what im trying to say?
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Your analogy is misleading. Without getting too indepth into the physics side of things, given the bricks and feathers, a net acceleration of 9.8 m/s is acted upon it downwards due to gravity. Thus for any given distance, they will both hit the ground at the same time (ignoring air resistance). However, with your two cars, they do not accelerate at the same rate (and this is the key). Given a car has 150 HP and weighs 1900 lbs (and I'm assuming your keeping torque constant between the two cars, too), the engine can only translate that into a certain amount of energy to drive the vehicle forward. Because this car is lighter, it can accelerate faster (using formulas for power, kinetic energy and acceleration/velocity). Thus the acceleration is a function of the vehicle's mass (ie, it is dependant on the car system, rather than an external acceleration due to gravity). So, the lighter car accelerates faster. Or something.

This post has been edited by CoSo: Oct 25, 2005 - 3:34 AM

[CoSo]

there is a huge difference from somethign falling as apposed to somethign needed to be able to pull it....  like think you tring to pull its like think try pulling a beg of briks with ur hands and then try pulling a bag of feathers...  which one will u be able to pull faster?
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If they both weigh 1 pound, and given a constant kinetic/static friction coefficient, it'll be just as much work. Work = F.s (where F = Force = mass*acceleration, s = distance).

[behindthesmile]

this whole theory is going off something i remember someone saying before. not sure of the exact numbers, but it was something like "every 125lbs you take out adds 4hp" or something like that. anyway, the point is there is a direct correlation between weight and  HP.

now onto my main point. people talk stuff like "car A will beat car B becuase they both have the same HP, but car A is lighter" so if car B was reduced to the weight of car A, it would be faster? answer: no car b and car a would be equal since car a's advantage is taken off like if car A is 1900lbs and 150hp, and car B is 2700lbs and 150hp, wouldnt they both be the same speed?answer: they do have the same speed but carB would be slower since the extra 800lbs would weight it down compared to the carA but if car b loses that extra 800lbs then both cars would be equal its like that old trick question "which would fall faster, a pound of bricks or a pound of feathers" where they'd both fall the same speed. so wouldnt a 1900lb car with 150hp go as fast as a 2700lb car with 150hp? answer: no the 1900lb car would be faster than the 2700lb car
does anybody get what im trying to say?
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[soulshadow]

Wats up with all this formula stuff??

Simply put, more weight = slow ass car
less weight = faster car

Ex.
If you put our engines in a camaro. The thing wouldn't even budge cause its pushing something so heavy.

That's also the conecpt where civics come in. They are light yet they have a powerful dohc engine qucik enough to cream our cars.

[CelicaZR]

I'm not having a go at anyone here ok.
Is it just me or is people only interested in speed nowaday.
I understand that speed is a factor in a car.
But it is only a small factor.
You cant really use all the car's potential on the road.
Sure you can use it on the track, but how often you go you?
For me the Celica makes up for the lost in speed in other areas.
I know most of you'll agree while others will disagree,
but everyone is entitled to their own opinions.

[celicaST]

first off, you need to understand that the physics involved in the dynamics of a car are very complicated and can not effectively be conveyed as simple ideas to determine how fast a car is. all other things being equal though a lighter car will be quicker than a heavier car because power is the rate at which energy is transfered into/out of a system. so the more power the car has, the quicker the car can gain kinetic energy, which is 1/2*m*v^2. so given the same power for the same amount of time, obviously the lighter car will have been accelerated to a higher velocity. again, this is way over simplified and there are many other factors involved, but thats the general idea for you.

[BBoYRuGGeD]

its like im back in physics class....

i read somewhere in a car magazine that every 100lbs (or was it 200lbs?) shaves .1 sec (or was it .01 sec?) in ur 1/4 mile. i dont remember...maybe ill try and find that magazine

bboy

[forkee]

heres a good example.

the engine in the lotus elise has the same oomph as our engines, yet has the acceleration of a viper. so....lose 2000 lbs off the celica and u might be gettin somewhere.

[celicaST]

heres a good example.

the engine in the lotus elise has the same oomph as our engines, yet has the acceleration of a viper. so....lose 2000 lbs off the celica and u might be gettin somewhere.
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more around 600 i think , i found somewhere that an st auto weighs in at 2415 lbs. if you could drop it to around 1800 lbs, it would be pretty dang quick. nice thing about weight reduction is that it improves handling, mpg, braking, and acceleration all without engine mods that might hurt reliability. plus a lot of it is free! as long as you dont mind driving without ac, stereo, and a lot of other stuff. i have my spare and seats removed which doesnt really do anything, if your going to go the weight route you have to go all the way.

This post has been edited by celicaST: Oct 25, 2005 - 12:34 PM

[nik]

heres a good example.

the engine in the lotus elise has the same oomph as our engines, yet has the acceleration of a viper. so....lose 2000 lbs off the celica and u might be gettin somewhere.
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more around 600 i think , i found somewhere that an st auto weighs in at 2415 lbs. if you could drop it to around 1800 lbs, it would be pretty dang quick. nice thing about weight reduction is that it improves handling, mpg, braking, and acceleration all without engine mods that might hurt reliability. plus a lot of it is free! as long as you dont mind driving without ac, stereo, and a lot of other stuff. i have my spare and seats removed which doesnt really do anything, if your going to go the weight route you have to go all the way.
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but you forget you have to add your wieght + anything you added to the car like stero etc + the weight of the gas full tank half tank etc

[celicaST]

heres a good example.

the engine in the lotus elise has the same oomph as our engines, yet has the acceleration of a viper. so....lose 2000 lbs off the celica and u might be gettin somewhere.
[right][snapback]348820[/snapback][/right]

more around 600 i think , i found somewhere that an st auto weighs in at 2415 lbs. if you could drop it to around 1800 lbs, it would be pretty dang quick. nice thing about weight reduction is that it improves handling, mpg, braking, and acceleration all without engine mods that might hurt reliability. plus a lot of it is free! as long as you dont mind driving without ac, stereo, and a lot of other stuff. i have my spare and seats removed which doesnt really do anything, if your going to go the weight route you have to go all the way.
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but you forget you have to add your wieght + anything you added to the car like stero etc + the weight of the gas full tank half tank etc
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correct, i was just trying to point out that the celica is a pretty lightweight car to begin with. the US spec elise weighs just shy of 2000 lbs and can do 0-60 in under 5s with 180 hp if anybody was wondering.

[darksecret]

Not to complicate things but drag and traction must be considered also, think of it like this losing wieght is great ask Anna Nichole, but losing it in the wrong places will hurt performance as quick as help, in the Celica's case it is more of a low end torque based car (kind of like a domestic) well lets say you take wieght of of the front, now you'll have to add more wieght because you need to use wider front tires to keep the wheels from spinning, the trade of is good but it's not good enough for street use.

Also with drag using the Elise is a good example but it's apples and oranges compared to a Celica, the Celica has very aerodynamics compared to other cars in it's class but if you made the same power as an Elise and wieghed the same the Elise would still beat the Celica simply due to aerodynamics and really good wieght distribution seeing as how the motor is over the already wider wheels, then consider the suspension is set up better for a launch but that's really complicating things.

[RbrtNdrws]

Physics makes the world go 'round.

[Snarfer]

Easy way to put it F(forward wheels) = mass*acceleration, if the mass is divided in half and the force created by your engine then you will double your acceleration. I'm sure there are other things to take into consideration. As far as how hp plays into that will have to do with rpm bla bla too lazy to make a graph.

[Mr_E]

Not to complicate things but drag and traction must be considered also

Word.

Stick 400bhp in an Elise, and it won't accelerate an awful lot faster as it won't get any more traction.

It's where something like a Veyron murders a Mclaren F1. It's getting on for 40% heavier, but has superior traction due to more mass and 4wd, and bucketloads of torque.

[creis]

The real trick quetions is why does a wheel waigh more spinning then it does stationaly?

[celicaST]

The real trick quetions is why does a wheel waigh more spinning then it does stationaly?
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it doesnt weigh more