power to weight ratios

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Q: I cant work out power to weight ratios?
im only asking coz i want to know the p/w ratio of my motorbike

A: you take the power and divide it by the weight.

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Q: Scooter Power to weight?
Im looking a scooter and one thing in the spec of bike comfuses me the Power/weight ratio! It says that its 0.0562 HP/kg

Is that any good and could ya explain what it means?

A: Only the Chinese would list power to weight instead of actual horsepower. They do this because their scooters are slugs.

The power-to-weight figure is useful to understand how well a vehicle will accelerate, but in North America it is usual to expressed as the weight (in pounds or kilos) each horsepower has to move instead of the more esoteric how many horsepower are available to move each pound (or kilo). Everything else being equal, a good power-to-weight is an indication of better acceleration and fuel consumption. For example a 500lbs 100hp motorcycle can easily outrun a 4000lbs 400hp car because the bike has the much better power to weigh ratio of 5lb/hp vs 10lb/hp.

In your scooter’s case the power-to-weight works out to 39lbs/hp, if my math is right. That’s not very good…

Q: Which insect has the highest power-to-weight ratio ?

A: Just a guess,but I would say……the Ant.

Q: 2001 C5 corvette , I need to reduce the weight for better power to weight ratio … What can I take off?

A: Well it all depends. Are you wanting to race your car? I am assuming so… but like someone said above the seats, the AC can go too… they are heavy !!! Pretty much anything not needed to get you around the track.

We own a performance shop in Florida and specialize in Corvettes, we also have a race team.

www.motorsportsxtreme.com

Q: Power, weight, speed, and gear ratios?
I’m lost and tired of pulling my hair out on this one. I want to move 265lbs 59ft/sec with a 1.3HP motor (1000 watts). So actually its my weight (165lbs) plus the weight of the scooter (100lbs) at a speed of 40MPH (59ft/sec) with a 1000 watt motor (1.3HP). The small gear on the motor i believe is 12 teeth, so what size rear sprocket would i need to reach a top speed of 40MPH. I believe the motor has around 3000rpm (maybe 2600) I know that 1000 watts = 715 ftlbs/sec, but i’m missing something here. lol and its 3 am. thank you

A: There are two issues here:

1. What gear ratio do you need to have the 2600 rpm motor spin the wheels of the scooter at 40mph (you need the wheel size to compute this).?

2. Is 1000w enough power to move you and the bike at 40mph; overcoming gear friction, rolling resistance, and air drag? It’s probably not (based on my experience with bikes). Air drag is actually the biggest load in this, and sitting up on a scooter is not exactly areodynamic.

Q: wolud a majic ant be able to withstand a high power to weight ratio and win every fight it had even?
fight that it had even withother ants that werent majic like the majic ant

A: He would be able to perform any task that his magic (and your fantasy) allowed him to do.

Q: Serious question about Power To Weight Ratio..?
When the torque is 235 Lb ft, and the Hp is 165, how do you do this? It has 37 more ft lbs torque than the vehicle Im comparing, but 25 less Hp.

They are the same weight.

A: At the rear wheels? It is all in the gearing, the drive ratio is what will determine the torque output, I could pull a house with a lawn mower if you gave me a big enough gear to do it with. If you are talking about torque at the end of the crankshaft, then it is done with cam timing and compression ratios. The longer the power stroke burn time before the exhaust gas is released will result in a longer power stroke, thus making more rotational force on the crankshaft. This is why a diesel engine has such impressive torque numbers, it’s power stroke has a longer burn time in the cylinder than a gasoline engine.

William: The slower revolutions of the diesel further explains my point, the diesel fuel also burns slower than regular gasoline. Most modern diesels also inject more fuel after the point of ignition, to make the burn even longer and help quiet the “clacking” noise from the detonation, the Fords do at least. The question was for power to weight, but as you can see, there was no weight given, just torque and horsepower comparison. The longer the burn time, equals more torque. Plain and simple, just as I stated.

Q: what is meant by power to weight ratio in automobiles?

A: Power to weight is a measure of acceleration. The more horsepower per pound, the more force you can apply to the ground to accelerate, the sooner you get to 60 MPH, or the sooner you cross the finish line. Spaceflight is the ultimate in horsepower to weight.

Q: similar weight to power ratio with different 1/4 mile times?
how come i see lotus elise running 13 sec 1/4 mile and crx’s with almost the same pwer and weight specs but the crx is running 15’s?
now that i think about it im sure downforce has a say in it as well?

A: The main reasons are:
the Lotus produces 189 hp, as opposed to the Crx V-Tec, which makes only 160 hp.
the Lotus produces 133 lbs ft torque, the Crx, 112 fts ft. torque. (max)
the Lotus has a 6 speed close ratio transmission, the Crx uses a 5 speed

Plus the fact that the the Lotus has a much better front/ rear balance than the production line Crx.

Lotus has done only 1 thing since 1950- build finely tuned performance autos. Honda, on the other hand, makes cars, motorcycles, outboards, ATVs, PWCs, lawnmowers, etc. It’s all about focus.

Q: A power to weight question….?
Keeping it simple, lets say I have a moped that weighs 100lbs with a 5hp motor on it. That equals a power to weight ratio of 1/20 right?

Now I have an older SUV that weighs 4000lbs with 200hp, that is also a power to weight ratio of 1/20, right?

Or am I doing the math wrong?

A: You are doing it right, but if you add a 150 lb driver, you need to recalculate.

Q: what is the power to weight ratio of a koenigsegg ccxr 2009 edition? ?

A: Whatever it is, look up its power output, and its weight. Divide its power output by its weight, and you will have a ratio of power to weight.
What units you use is up to you. The answer of the division will be “X” / 1. e.g. 100kW/ 1000kg etc.

Q: Experts: What power comparison is better in drag racing?
Hp to weight ratio?
-or-
Torque to weight ratio?

I raced a vehicle the same mass as mine, he had 235 pounds of torque, but 170 Hp, while on the other hand, I had only 188 pounds of torque with 190 Hp and his vehicle smoked mine.

I can do 120 mph and he can only do 80. Thats the catch. Which comparision do I use to compare the power to weight ratio? Mine beat his for the first sec, then he swiftly passed me and kept going. We are both automatics.

Please don’t go into gearing, we were in our 2-3 gears (on drive) and he is the quicker one. It had something to do with torque. Thanks.

A: You want a better horsepower to weight ratio. Torque is good to get a holeshot, but if you lack horsepower you will just fade away. Torque usually kicks in between idle and 2000 RPM, so basically once out of first, torque is useless. Horsepower, on the other hand usually kicks in at around 3000 to 6000 RPM, and since your shifting gears just about at redline, you stay in the horsepower curve the entire time. Ideally, you want both torque and horsepower, and usually torque will be the bigger of the two, but not always. It sounds like he just has a better setup, he has alot of torque to get the holeshot, and enough horsepower to keep ahead of you although you gain speed because you have more horses, if you have a conical air filter, it will affect the low end torque of your car, in effect you lose it. But it will provide more high RPM horses. And really, you may want to see if he has a cheater NOS system, or a stall converter. But having 47 more foot/pounds, he should be able to smoke you from 0-60 foot and 1/8, then since your horses are almost the same, your 20 more horses just ain’t enough to make up for the lack of torque. If you had 235 horses, then you could probably take him. In effect, I have an Excursion, with a Triton V-10, and I kinda street raced a diesel Excursion, I have approx. 325 horses and I am not sure of the torque, but it is prolly somewhere around 300 to 350. The diesel has like 470 foot/lb, and 300 horses, anyway, we left the light and I took the holeshot, once his turbo spooled up, he blasted by me like nothing, but once we hit around 45 to 50 MPH, I pulled away from him. So you can see, the horsepower and torque combined let me take the holeshot, but as engine speed increases, his torque kicks in, while I am in between max torque and horsepower, so he began to pull away… FAST!!!! but then as engine speed increases more, his leaves his torque curve and since I had more ponies, I pulled from him. But, to answer your question, you want a good H/P to weight ratio…

Q: Power to Weight Ratio?
What is it and what kind of number should I be looking for?

A: If you divide the weight of your car – say 2,000 lbs by the engine horsepower, let’s say 200 bhp to keep the math easy, then your power to weight ratio is 10 lbs per horsepower. That means that your car has one horsepower for every ten pounds that have to be moved down the road.

All other things being equal (which they never are) your car would be faster than the guy who’s power to weight is 15 (meaning he is pulling 15 lbs for every horsepower). I’m not a “car guy” and I can’t say what the “right” number is, but you might try putting together a spreadsheet of the cars in the class you’re interested in and calculating their respective power to weight ratios and that should give a good idea what the range is.

It would also be interesting to compare their performance – if you can get the data (say quarter mile times, or 0 to 60 times) and see how effective the power to weight ratio is at predicting the car’s performance.

Q: formula for power to weight ratio?

A: power to weight ratio = power/weight.

In quoting it, you must give the units, e.g.
horsepower per ton, watts per pound, kilowatts per kilogram…

Q: What is God’s power to weight ratio?

A: E=MC2, so universe = infintie mass, Energy= infinite times.

Speed of light squared is will power.

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