Big torque anyones here ?

[stuartturbo]

This is possible a repost
430Nm
whilst view this was listed is it anyones here as the torque seems massively high and the power is quite good
and

[Spirit]

I think the second one is Richieelliott's.......and done at AP Motors in Plymouth

[Axeboy]

I was told (possibly wrong) that torque is near impossible to estimate with any accuracy on the rollers..

Might have been the RR i was at mind.

They can give "values" such as this one below... but they mean zip in terms of Nm/lb.ft etc

[Axeboy]

However..

Can it be calcualted through RPM and Power?

Hmmm

My peak torque is at approx 2500rpm....

And at 2500rpm, my wheel power was: 131.4hp

Calculated out this is 276 lb/ft = 374Nm


Hmmm, could be right.

[Kieran]

The vid of the blue one is Dan_G's car I think.

[Axeboy]

And the standard car is 267 lb/ft or 361Nm

But thats at the fly, not the wheels I assume.

[Nutter_John]

Right on Fly is correct

[g6acb]

Why do most rolling roads run with the bonnet up??? - I mean I know why but its not as if you drive down the street with the bonnet up is it??

[OSiRiS]

Why do most rolling roads run with the bonnet up??? - I mean I know why but its not as if you drive down the street with the bonnet up is it??

Just ease of installing/removing sensors etc.

And besides, they'll have a fan at the front of the car to stimulate air pushed towards the front of the car for intercooler etc. Obviously on the dyno air resistance isn't a problem.

[g6acb]

Yeah, I have been on several dyno runs.... but personally run it with the bonnet down i.e replicating real life driving conditions - but then there is one less sensor to fiddle with and no intercooler for me ......

[Wodjno]

Yeah, I have been on several dyno runs.... but personally run it with the bonnet down i.e replicating real life driving conditions - but then there is one less sensor to fiddle with and no intercooler for me ......

Running with the bonnet Down or Up will not replicate real driving conditions

The reason being that ! No matter what BIG Hairdryer the Rolling Road have situated in front of the cars grill when on a power run ! It will never replicate the air flow of real driving conditions..

If you have a normally aspirated car then you are not getting the air Rammed into the intake at the rate you would be if you were acelerating hard

Also, if you have a forced induction car you will not be gettin also the cooling affect of the air being forced through the Intercooler and cooling the charge air

Also 430nm is only 317 ft lbs of touque

Is that really excessive

[stuartturbo]

Also 430nm is only 317 ft lbs of touque

Is that really excessive

OK rechecked the must have been a stupid moment
I blame the online conversion i knew it was about .74Lbft to a Nm but used the figure given without thinking

[psbarham]

However..

Can it be calcualted through RPM and Power?

Hmmm

My peak torque is at approx 2500rpm....

And at 2500rpm, my wheel power was: 131.4hp

Calculated out this is 276 lb/ft = 374Nm


Hmmm, could be right.

dynos measure torque , then using a sum they work out power , basically torque x revs

have a read of this


TORQUE
Torque is a twisting force about an axis of rotation. It is measured in units of force times distance from the axis. When you tighten a bolt you exert a torque on it. If the spanner is 1 foot long and you exert a force of 10 pounds on the end of it then you apply a torque of 10 foot pounds. If the spanner is 2 feet long then the same force would apply a torque of 20 foot pounds. Whether the torque applied creates movement or not is a separate issue. If the bolt has already been tightened to a torque of 50 foot pounds and you apply a spanner to it using a torque of 20 foot pounds then it won't move any further.

WORK
Work is also measured in units of force times distance but there is a subtle distinction between Torque and Work. For work to take place there must be movement involved. Work can be defined as the product of force times distance moved. Lets imagine we have a sack of grain on the floor weighing 100 pounds and we want to lift it onto a table 3 feet high - we would need to do 300 foot pounds of work against gravity to achieve this. Copyright David Baker and Puma Race Engines

POWER
Power is the rate at which work is done. The more power a thing generates, the more work it can do in a given space of time. Lets imagine we ask a small child and an adult to both lift the sack of grain above onto the table. The adult might be able to lift the whole sack in one go but the child would probably not. However the child could take a pan and lift the grain one panful at a time until the whole 100 pounds was on the table. It would take longer but the end result would be the same. Both the child and the adult would have done 300 foot pounds of work but at different rates - we can therefore say that the adult was more "powerful" than the child.

If the adult lifted the whole bag in one go in 5 seconds then he would have done work at the rate of 300 foot pounds in 5 seconds - i.e. 300 x 60/5 = 3,600 foot pounds per minute. If the child took 1 minute with the pan then his rate of doing work would be 300 foot pounds per minute - only 1 twelfth the rate of the adult. In other words the adult generated 12 times as much power as the child.

The more power a car engine generates, the more work it can do in a given period of time. This work might be driving the car at high speed against air resistance, moving the car up a steep hill or just accelerating the car rapidly from rest. Copyright David Baker and Puma Race Engines

HORSEPOWER
It was James Watt who refined Newcomen's steam engine design and turned it into a machine capable of doing work at a reasonably efficient rate. The most common applications of steam power in the early days were pumping water or lifting coal from mines. As far as coal is concerned it was horses that did most of this work before the coming of steam power.

Watt needed to be able to rate the power output of his steam engines in order to advertise them. He decided that the most sensible unit of power to compare them to was the rate at which a horse could do work. He tested the ability of a variety of horses to lift coal using a rope and pulley and eventually settled on the definition of a "Horsepower" as 33,000 foot pounds per minute - or 550 foot pounds per second. In fact the horses he tested could not keep up a steady work rate as high as this (he actually averaged them at 22,000 foot pounds per minute) but being a conservative man he added 50% to the rate he measured in case other people had more powerful horses than he had tested. Maybe modern engine builders might take note of the good sense of James Watt and not be quite so optimistic in the power claims for their own engines!!

So a horse walking at a comfortable speed of 5 feet per second would need to raise a weight of 110 pounds to do work at the rate of 1 Horsepower. Not so hard you might think - in fact a strong man can do that amount of work - but only in short bursts. A horse can easily do work at a faster rate than this but again not without rest. A steam engine, provided you keep it fueled can run continuously. Watt's measurement was designed to take account of the fact that machines can run for ever but animals or men need to stop and rest from time to time. Copyright David Baker and Puma Race Engines

BHP and HP
All the B means is "brake". The old word for a dyno - because the engine torque was measured by applying a brake to the flywheel rather than a torque converter or electrical motor which is how it's done nowadays. There's no other difference between the two and they both just mean horsepower.

HOW TORQUE AND POWER RELATE
The final part of the story is to see how we calculate power from torque or vice versa. Let's imagine we have a pulley at the top of a mine that is 1 foot in radius - or 2 feet in diameter. At the bottom of the mine, at the end of a rope leading round the pulley is a bag of coal weighing 100 pounds. Instead of using a horse to pull on the rope let's connect an engine to the pulley - perhaps by bolting the pulley to the crankshaft of the engine.

In order to lift the coal we need to apply a torque of 100 foot pounds to the pulley because the coal is pulling down with a force of 100 pounds applied at 1 foot from the axis of rotation. In other words the Torque applied is the Weight times the Radius of the pulley. If the engine turns the pulley at 1 revolution per minute how much work is being done?

Well for each turn of the pulley the coal will rise the same amount as the circumference of the pulley which is 2 pi times the radius = 3.14 x 2 = 6.28 feet. So in 1 minute the engine will do 628 foot pounds of work. Copyright David Baker and Puma Race Engines

We can rearrange the above in terms of torque and speed:

The rate of work being done (or Power) is Force x Distance per minute = Weight x radius x 2 pi x rpm foot pounds per minute. However we already know that Weight times Radius = Torque so we can equally say:

Power = Torque x 2 pi x rpm

To turn this into Horsepower we need to divide by 33,000. Our final equation therefore becomes:

Horsepower = Torque x 2 pi x rpm / 33000 which simplifies to:

Horsepower = Torque x rpm / 5252.

This is the universal equation that links torque and horsepower. It doesn't matter whether we are talking about petrol engines, diesel engines or steam engines. If we know the rpm and the torque we can calculate horsepower. If we know horsepower and rpm we can calculate torque by rearranging the equation above:

Torque = Horsepower x 5252 / rpm

Hopefully you can also see that when an engine is turning at 5252 rpm, its torque and horsepower figure is the same. Next time you see a graph of the torque and horsepower of an engine check to see that the lines cross at 5252 rpm. If not then the graph is wrong. This only applies of course if the power is being measured in horsepower and the torque in foot pounds and both lines are shown on the same axes. There are many other units in which torque and horsepower can be measured - for example power can be measured in Watts and torque in Newton metres. Unless we need to convert to such continental measures we can usually stick to horsepower and foot pounds.

One measure to be aware of though is the "continental horsepower" or PS. This stands for "PferdeStarke" - the German translation of "horse power". In France you sometimes see the same measure being called a "CV" for Cheval Vapeur. This measure was chosen in Europe as being the closest thing to a horsepower that could be expressed in nice round metric units - 75 kilogramme metres per second to be exact. It is commonly used by car manufacturers nowadays and tends to get used synonymously with bhp although it is actually a slightly smaller unit of power. One PS is about 98.6% of one bhp. The conversion table below covers the units most commonly used to express power and torque.


To convert from: To: Multiply by:
BHP PS 1.01387
BHP Ft Lbs/second 550
BHP Watts 745.7
PS Kg M/second 75
PS Ft Lbs/second 542.476
PS Watts 735.5
Kilowatts BHP 1.341
Kilowatts PS 1.360
Lb Ft Nm 1.356

[djb160]

Good article

[bradc]

http://www.hondahookup.com/info/hors..._vs_torque.php

This is a good article as well that explains all about how torque, horsepower and gearing are all related