rolling road graphs

[Russ_16v]

just discussing these with a friend and he said all graphs bhp and torque should cross at 5252 rpm, no matter what engine, is that right?

this is the site he said to look at

http://www.pumaracing.co.uk/POWER1.htm

 

[TheEvilGiraffe]

Makes sense from this equation (off that site) ...

Torque = Horsepower x 5252 / rpm

 

[Russ_16v]

thats what i mean, is that site accurate?

 

[TheEvilGiraffe]

Infact all that adds up ... most of what is written is correct, if i remember correctly from Uni !

Only thing that seems to be made up / pulled out the air as not explained is the 33,000 figure but wikipedia and other sources suggest it is the amount of work a pony can do.

The term "horsepower" was coined by the engineer James Watt in 1782 while working in the performance of steam engines. This occurred while using a mine pony to lift coal out of a coal mine. He conceived the idea of defining the power exerted by these animals to accomplish this work. He found that, on the average, a mine pony could pull (lift by means of a pulley) 22,000 foot-pounds per minute. Rather than call this "pony" power, he may have increased these test results by 50 percent, and called it horsepower i.e. 33,000 foot-pounds of work per minute.

..from http://en.wikipedia.org/wiki/Horsepower#Horsepower_from_a_horse
:approve:

You have to have your torque figure in lb/ft not Nm tho

 

[Russ_16v]

the only thing that confuses me is if that it true, that all graphs should cross at 5252rpm no matter what engine then how come things like honda vtecs dont as vtec isnt engaged then, and how come iv never heard this meantioned on here before lol

 

[TheEvilGiraffe]

Need to get data on a few engines at 5252RPM and see what it looks like to clarify !

I think it should be taken with a pinch of salt, as most diesel engines don't rev that high anyway ...

I don't think you should be losing any sleep over this Russ !!

 

[Russ_16v]

lol na im not matey iv just never come across this before, and as iv never seen it mentioned i thought id ask, any tuners wish to clarify this for me?

 

[Ian_182]

Diesels wont cross that high

 

[drhowser]

i'm sure that is right, i can't remember if the numbers are right. but the graphs should cross at the same point.
i've definately heard about this before.