UK Horses V American Horses!

Guys,

I will soon be taking my 393 Windsor for dyno & will post the results on this forum for review. However I live in the UK & will obviously have the dyno done in the UK which leads me to my question. Am I right in saying there is a difference between the UK HP & US HP unit or does this only relate to production car HP figures? I have heard a US HP is slightly more than the UK unit, i.e if an engine was dynoed in the UK & acheived say 500hp & then the same engine dynoed in the US & acheived 550hp?

Regards,

Martyn

It makes no difference where you live.....hp is hp....as long as its corrected back to the same rating, usually SAE?

You are correct. Metric HP is not the same but you have the relationship backwards. 1 metric HP is less than 1 HP. Sorry CMF60...[img]/forums/images/smiles/icon_frown.gif[/img]

Definition:
metric horsepower
a unit of power, defined to be the power required to raise a mass of 75 kilograms at a velocity of 1 meter per second. This is approximately 735.499 watts or 0.986 32 horsepower. The unit is known in French as cheval vapeur, in Spanish as caballo de vapor, and in German as Pferdestärke.

horsepower (hp)
a unit of power representing the power exerted by a horse in pulling. The horsepower was defined by James Watt (1736-1819), the inventor of the steam engine, who determined after careful measurements that a horse is typically capable of a power rate of 550 foot-pounds per second. This means that a horse, harnessed to an appropriate machine, can lift 550 pounds at the rate of 1 foot per second. Today the SI unit of power is named for Watt, and one horsepower is equal to approximately 745.6999 watts. (Slightly different values have been used in certain industries.) Outside the U.S., the English word "horsepower" is often used to mean the metric horsepower, a slightly smaller unit.


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<font size=-1>[ This Message was edited by: allenman85 on 12/5/06 6:51am ]</font>

So basically you're talking about a 3kW difference for a 350HP motor. Hooray significant figures.

<font size=-1>[ This Message was edited by: thekingofazle on 12/7/06 10:01am ]</font>

Something like that. Hey, I didn't invent the stupid thing. [img]/forums/images/smiles/icon_smile.gif[/img]
Bugatti announced their 1016HP engine (Veyron) last year. Fine print said Metric HP. Actual was only 996HP. [img]/forums/images/smiles/icon_smile.gif[/img]


[addsig]

Correction factors available to most dyno operators are thru the software are -

DIN
ECE
J1995
JIS
SAE
STANDARD

He is talking about dyno results from his engine allenman.....not a definition of hp....[img]/forums/images/smiles/icon_frown.gif[/img]

Unfortunately he IS asking about dyno HP differences which my answer gives. Your reply should be deleted as it has no place here.
Correction factors are not the conversation -- metric (UK) vs STD is at debate.
Thanks for playing.
[addsig]

<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font size=-1>Quote:</font><HR></TD></TR><TR><TD><FONT SIZE=-1><BLOCKQUOTE>
On 2006-12-10 17:02, allenman85 wrote:
Unfortunately he IS asking about dyno HP differences which my answer gives. Your reply should be deleted as it has no place here.
Correction factors are not the conversation -- metric (UK) vs STD is at debate.
Thanks for playing.

</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR></TD></TR></TABLE>

Oh, but correction factors ARE the conversation.
Did you know a dyno measures torque...not hp? From there it is "computed" to hp (only torque and speed can be measured...hp can't)....the operator can select from any one of those correction factors. So if the man wants to compare his engine to a US engine, he tells the operator to use the US correction factor....simple eh?
It appears that metric is also not the hard and fast rule in the UK...as I suspected - from Wikipedia - "Companies of the United Kingdom often intermix metric horsepower and mechanical horsepower depending on the origin of the engine in question."

Thanks for coming....

I did not like the tone of your reply and you obviously didn't like mine....so now we are square....and my posts stay.

I thought HP ratings could be corrected by SAE and so on. That the reason all the car companies started doing SAE so they all would have a fair playing field. Because earlier on one car company could boast 350hp using say a dynojet with no correction, and another could say they had 350hp SAE corrected. My understanding was that if you take the SAE corrected motor and put it on the dyno jet with no correction it would put down more HP.