Banyaknya yang mempersoal tapau-menapau sesama motor. Jadi aku akan explain dari segi engineering (ambik elektif dulu automotif engineering):
1) Torque determines the acceleration.
2) Horsepower determines the top speed.

Dua-dua mempunyai hubungan:


Ini basic untuk torque dan horsepower. Lepas tu:
1) The lighter the vehicle, the faster it accelerates. The heavier the vehicle, the slower it accelerates if both of the vehicle have the same torque.
2) Vehicle with higher air drag will have lower top speed, vice versa for both vehicle with the same horsepower.


FD is the drag force, which is by definition the force component in the direction of the flow velocity,[1]
rho is the mass density of the fluid, [2]
v is the velocity of the object relative to the fluid,
A is the reference area, and
CD is the drag coefficient – a dimensionless coefficient related to the object's geometry and taking into account both skin friction and form drag.
http://en.wikipedia.org/wiki/Drag_equation

Untuk hubungkan drag force sama horsepower (untuk overcome the drag force at high speed):
P = F.V
P: Power
F = Drag force
V = vehicle speed

Dari formula drag force boleh lihat drag force increases exponentionally dengan peningkatan vehicle speed, sebagai contoh:
Katakan drag force untuk 50 km/h = A
drag force untuk 100 km/h = 4A
drag force untuk 150 km/h = 9A
drag force untuk 200 km/h = 16A

Macam mana dapat 16A untuk 200 km/h? Bahagikan 200 kuasa dua sdengan 50 kuasa dua = 40000/2500 = 16

Sebagai contoh horsepower kereta dengan top speed yang boleh didapati:
100 km/h = 20hp
190 km/h = 110hp (god car, waja, honda siti nurhaliza)
260km/h = 280hp (subaru imprekzaaa, lancer evo ori, lancer evo tiruan wiralution)
410km/h = 1000hp (veyron)

Boleh nampak semakin tinggi top speed, gila vavi horsepower diperlukan.


Jadi kapcai dengan 9hp mahu tapau KTM 390 dengan 44hp, jangan harap lah! lol
kapcai yang sudah gila babi modify pon boleh cecah 160km/h jek.
Satu-satunya kapcai yang boleh lawan ialah kapcai 125z cub prix, ini gila vavi laju.

This post has been edited by terradrive: Sep 17 2014, 06:18 PM

Torque is the rotating force along a shaft, it is translated back into translational force by the wheels.

This is why a Silvia S15 has faster 0-100km/h time than a Honda S2000, both have about the same weight and horsepower. But the force exerted by the wheels of the Silvia is larger than the S2000 (because of higher torque), thus it accelerates faster. Remember F=m.a, so a = F/m

Check back the equations I posted, it explains the role of horsepower & torque in overcoming the mass of the vehicle in acceleration combined with the effects of aerodynamic drag.

If you change the final drive ratio, you changed the rpm & torque produced. But power only affects the acceleration at higher vehicle speeds because at high vehicle speeds the aerodynamic drag is pushing the vehicle back.

Dyno shows results in power & torque, check back the charts.

Refer to the equation I posted before, torque and power isn't the only parameter, you have to factor in rpm.

If you want to see the effects of torque and power, you have to set the other parameters to be the same:

Checking the effects of different torque values:
1) Both vehicle A & B have same weight, same horsepower, same aerodynamic drag (same shape). Vehicle A has double the torque than Vehicle B.
Results: Vehicle A will accelerate faster to top speed than Vehicle B but both will have the same top speed.

Checking the effects of different horsepower values:
2) Both vehicle A & B have same weight, same torque, same aerodynamic drag (same shape). Vehicle A has double the horsepower than vehicle B.
Results: Vehicle A will have higher top speed than Vehicle B, in addition, vehicle A will accelerate faster than vehicle B because vehicle A have higher rpm (check back the power to torque equations, with the same torque value, higher power means rpm must be higher). This is simply because when the vehicle A have higher rpm, it can hold on to the gear longer than vehicle B. When vehicle A is still on gear number 2, vehicle B already shifted to third gear and have to accelerate with lower torque even at the same speed as vehicle A.

When comparing the effects of certain parameter/variable. All other variables must be controlled or made constant. This is standard practices. If you try to claim the effects of the parameters without doing that, those scientists/engineers would laugh at you man.

Gearing/gearbox doesn't affect the outcome at all. Gearing ratios are calculated from the given engine's power and torque chart. The one that would affect the outcome is the difference in torque and power chart between engines. There are optimal gearing ratios for every car, if you're talking about adjustable gearing ratios to fight on drag strips, sorry but that's for racing purposes and doesn't apply to production cars.

Every naturally aspirated Internal Combustion Engine have the characteristics as you said. But you need to understand that the peak torque range is affected by:
1) Camshaft timing & lift
2) Shape of the combustion chamber
3) The design of cylinder heads (number of valves and position)
4) Shape of the intake manifold/plenum
5) Shape of the exhaust manifold/plenum
6) Length of intake manifold
7) Length of exhaust manifold
8) Length, dimension, and equipments installed on exhaust (4-2-1, s-flow or straight mufflers etc)

There are many factors that determine the torque curves, for example the shape of the combustion chamber, valves, intake manifold exhaust etc etc affects the speed of the intake gas going into the cylinder. Different configurations affects different volumetric efficiency of the engine at different rpm because the ideal engine must have different configurations for different rpm for optimal engine performance at every rpm. This is the reason why manufacturers introduced variable valve timing and lift technologies. Here's some additional info for you, there will be a choke point at which if the speed of the intake gas is higher than the speed of sound, the total volume of the gas that are able to go into the combustion chamber will be dramatically lowered with the added speed.

Did you noticed that normal cars have max torque at lower rpm range to help with drivability while high performance naturally aspirated cars have max torque at really high rpms?

That's just naturally aspirated cars What about forced-induction cars? Turbocharged cars are totally different, take for example a Toyota Supra with twin sequential turbochargers. 90% of the max torque (325 lb ft) of the 2JZ-GTE engine is available from 1300rpm onwards.

You said that max power rpm must be higher than max torque rpm, but why the chart above indicates the max torque rpm is the same with max power rpm, is this blasphemy? No, sorry just great engineering.

Sorry man haha, engineers tak bleh tahan kalo tak defend balik fakta.

This post has been edited by terradrive: Sep 18 2014, 01:18 PM

Sure, but as I said, as in previous post I'm explaining the different effects of the torque and horsepower. When comparing things everything else must be the same.

Remember even graphics's card reviewers would use exactly the same computer to benchmark many different graphic cards. If one system using AMD FX6300 + GTX 780 Ti compared to Intel 4670K + AMD R9 290X. The results of the benchmark cannot be compared because the computer systems used were different.

Talking about different gearbox would be another matter when we are discussing about torque and horsepowers.
If you want to talk about gearbox then the all others have to be constant to evaluate the pro and cons of different gearboxes.

I put out the chart just to remind you that different engine designs give different power/torque charts...

In the end just refer back to the most basic, paling basic punya 3 equations I posted before.

Ok soli soli i stop now.

nak kasih balik pangkal jalan.

Lampu motor KTM ni banyak hodoh cam beruk man.

Haha I dunno about riding at 180km/h
My biggest bike was 400cc last time, travel around 90-140km/h only. Over 140km/h got alot wind pressures, maybe can if you install motorcycle windshields. Z800 maybe better for traveling at 180km/h, Duke 690 hp abit low so making it to run 180km/h constantly can stress the engine.