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Location:
mel
Registered:
March 2004
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Location:
Melbourne
Registered:
October 2003
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Re: Why do people want high power car??
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Thu, 11 March 2004 01:36
 
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the torque increase is used to overcome forces such as inertia which can be massive in big cars (anythign bigger than a classic celica:) )
From what I know, torque is a result of the power produced. Therefore you'll get more torque with the higher power. This torque is what you want to get those wheels spinning at high speeds sooner. When thinking of f=ma you need to look at the whole system - The car.
remember all the time you have wind and air resistance that grows with the speed of the car.
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Location:
Brisbane
Registered:
May 2003
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Re: Why do people want high power car??
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Thu, 11 March 2004 02:00
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Power = torque * rpm
basically high torque = high power, depending on where that torque is in the rev range. High torque at high rpm = high power. High torque at low rpm = medium power, low torque at high rpm = medium power.
Power is the number that matters with regards to acceleration and top speed. torque can be created by different gear ratios, sacrificing rpm for torque (revvy engines). The drivability of a car is related to its torque curve. A nice meaty torque curve will result in a decent amount of power anywhere in the rev range, so if you put your foot down at 2000rpm or 8000rpm the car will respond, and go. Some cars (and bikes) have a peaky torque curve, resulting in excellent performance in a certain rev range, but sluggish performance elsewhere in the rev range (race cars are a good example, made to be driven at high revs, therefore all the torque is at high revs)
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Location:
Melbourne
Registered:
March 2003
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Re: Why do people want high power car??
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Thu, 11 March 2004 02:37
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Just what is the coefficient to get from torque to power?
ie: torque X rpm x Coefficient = power (hp or kw?)
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Location:
Perth
Registered:
October 2003
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Re: Why do people want high power car??
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Thu, 11 March 2004 05:10
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Torque (Nm) = (Power(W) x 60)/(2xPixN)
N = revolutions (rpm)
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Why do people want high power car??
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Thu, 11 March 2004 06:27
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Nm = (9402 x kw) / rpm
or
kw = (Nm x rpm) / 9402
to estimate max power/torque, a well sorted engine will make abotu a maximum of 100Nm/L (some high performance bikes and cars get up to 105Nm) for boost, multiply by (1+Boost) (where boost is measured in Bar)
the reason people want more power is gearing.
two cars, with same torque, but one makes that torque at double the rpm, will be going faster in the same gear...
is all about gearing.
Cya, Stewart
ps, search for the "Torque" thread
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Location:
Melbourne
Registered:
May 2002
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Re: Why do people want high power car??
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Thu, 11 March 2004 07:18
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I really could not be bothered with the physics lesson reading the whole thread, but in answer to the question asked, i think you will find that you need a car with power aswell as toruqe, this will become more important when the weight of the car increases, generally you need to develop the power early in the rev range to get the car moving, hence you need more torque and thats generally why larger capacity engines are placed in heavier cars, i think the ultimate goal to acheive high accelaration is a high level of force and a small amount of mass, as the equation a = f/m. So if you would like to GO FAST you would need something with high power, hig torque and low weight.
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Location:
mel
Registered:
March 2004
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Re: Why do people want high power car??
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Thu, 11 March 2004 08:56
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thanks everyone!
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Location:
Brisbane
Registered:
October 2002
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Re: Why do people want high power car??
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Thu, 11 March 2004 09:39
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| cozzb wrote on Thu, 11 March 2004 18:56 |
thanks everyone!
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um, yeh thanx, i have no idea what u said but it all looks legit
whats the velocity of the megabyte?????
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Location:
Canberra ACT
Registered:
August 2003
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Re: Why do people want high power car??
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Thu, 11 March 2004 13:34
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| oldcorollas wrote on Thu, 11 March 2004 17:27 |
Nm = (9402 x kw) / rpm
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kw = (Nm x rpm) / 9402
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I take it this is an estimate as well?
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Why do people want high power car??
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Thu, 11 March 2004 13:43
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no, that equation is mathematically EXACT (well to 4 sig figs anyways). you can check if you wish, by just doing the derivation. 1 inch = 2.54cm, 1kg = 2.2lbs,
the estimate is that a piston motor makes 100Nm/L...
for rotors it's capacity (eg 13B=1.3L) x 1.8 x 100Nm...
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Location:
UK at moment
Registered:
May 2003
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Re: Why do people want high power car??
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Thu, 11 March 2004 16:28
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Torque is the rotational analogue of force.
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Location:
Melbourne
Registered:
May 2002
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Re: Why do people want high power car??
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Fri, 12 March 2004 06:40
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My hooters have a lot of torque
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Location:
Tasmania
Registered:
May 2002
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Re: Why do people want high power car??
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Fri, 12 March 2004 07:09
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Most people want more power from their engine regardless of wether they have a V8, 4 or turbo car.
To have lots of power, you need either lots of torque, OR lots of RPM. You don't realy need both (but it would be nice).
V8's have lots or torque.
Twincams & rotarys have lots of RPM.
A Turbo will add to the torque.
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Location:
Sydney
Registered:
May 2002
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Re: Why do people want high power car??
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Fri, 12 March 2004 14:08
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1JZ-GTE
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Why do people want high power car??
