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Originally posted by Paul_J
The perfect example

N/A AC Cobra. 5 litre V8.

Makes peak power of 225 bhp @ 4200 but has 300 lb ft of torque @ 3000 rpm

NO FI.

http://www.pistonheads.com/fastcars/ac/cobra.asp

Merely only because it makes peak power so low (torque drops off quickly after its peaks / also peak torque is low).

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Originally posted by Jules S


A/. It's always been my understanding that its impossible to get higher lb/ft torque than BHP without forced induction? yes or no?

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Originally posted by Paul_J
I think the problem is, everyone's got obsessed with top gear etc, talking about torque and bhp like they're completely different things - totally unrelated.

Torque is the turning power, but to get a high power figure you need that torque to extend for as far as you can on the revs (or keep increasing ideally)

"A computerized engine dynamometer accurately measures torque and rpm and then can accurately calculate horsepower."

A rolling road isn't measuring power, it's measuring the torque (turning force) of the wheels - and the rpm at which this is . then using the formula I've already spoken about calculate the power.

Thus as I've said it before, if you have a car that makes all its power low down in the revs (like a Turbo Diesel) you get a larger torque figure than a peak power figure.

The reason it has so much torque is due to the turbo, the reason it makes the torque so low down is due to being a diesel.

This is a stupid and pointless post / question.

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Power and torque are just twin aspects of the same maths that determines how an engine performs and anyone wanting to tune an engine ought to benefit from a better understanding of the what the figures mean.

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

Most people have at least a vague idea what horsepower is but very little understanding of torque.

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Originally posted by Paul_J
http://www.pumaracing.co.uk/power1.htm

This explains what torque + power is, and how they are calculated. read it, it makes a lot of sense.

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Originally posted by Paul_J
Effectively based on that logic and answer to your original question jules S

Any car that makes peak power BELOW 5252 will have less peak power than peak torque

Anything that makes Peak Power above 5252 should have more peak power than peak torque.

Just due to how each are worked out.

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Originally posted by Paul_J
Yeh which is where you want it

Pff who wants shed loads of torque at 3k rpm and then it all disapears (ala most diesel turbos today).

The problem is, most of joe public has always fantastised about Peak BHP.

Now with more people talking about Torque, a lot of people fantastise about big peak Torque figures.

But at the end of the day, they're effectively talking about the same thing - what they should be looking at is how the torque is delivered and how useable it is.

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