How is Horsepower Rated across the Pond? (Top Gear TV Show)

I'm now completely addicted to Top Gear and a few episodes brought up the question above.

In an older episode I watched recently, the guys tested a Mustang GT500 and seemed surprised that after testing it on a mobile dynamometer, the rear wheel horsepower was less than the advertised rating (which is measured at the crank in the US.)

Similar examples appear in other episodes when they break out the mobile dyno. Again, they noted the "loss" of horsepower -- yet those cars were from England, France & Germany.

So…. I is confused. :_confused

All cars lose a percentage of power through the drive train. All car manufacturers say that their engines produce "X" hp but what they fail to neglect to mention how much the transmission and other gear boxes (if applicable) eat up. Not to mention all cars are different so each one's drive train will eat up a different amount of power.

That is just what I learned growing up if anyone cares to correct me by all means do so now as I am not an expert.

Horsepower at the rear wheels is always less then at the crank because of parasitic drag throughout the drivetrain. I believe it's measured the same regardless the country of origin, at the crank, when it comes to manufacturers claimed horsepower. The higher number is more impressive even though that's not the ponies at the rear wheels where it counts. I'm with you on the Top Gear addiction, I now have 78 episodes TiVo'd!

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Originally Posted by xXxRed_Ninty_9xXx

All cars lose a percentage of power through the drive train. All car manufacturers say that their engines produce "X" hp but what they fail to neglect to mention how much the transmission and other gear boxes (if applicable) eat up. Not to mention all cars are different so each one's drive train will eat up a different amount of power.

That is just what I learned growing up if anyone cares to correct me by all means do so now as I am not an expert.

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Originally Posted by Scott Larson

Horsepower at the rear wheels is always less then at the crank because of parasitic drag throughout the drivetrain. I believe it's measured the same regardless the country of origin, at the crank, when it comes to manufacturers claimed horsepower. The higher number is more impressive even though that's not the ponies at the rear wheels where it counts. I'm with you on the Top Gear addiction, I now have 78 episodes TiVo'd!

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Agree and agree! :) I just wondered if HP is measured differently in the UK since the guys always seem surprised about the "missing" HP.

Oh yeah, and the first episode of the US version airs Sunday Nov 21 on the History Channel. Good luck. :o

Difference in horsepower rating systems, couldn't find anything that identified a US-specific horsepower definition, but the table on this page shows differing conversion calculations depending upon the specific type of horsepower:

http://www.simetric.co.uk/si_hij.htm

Difference in pound measurement between the US and UK, which I assume would affect the calculated torque (express in lb/ft) for cars in each country:

http://uk.answers.yahoo.com/question...8053729AAnHU6A

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Originally Posted by RickOKC

Oh yeah, and the first episode of the US version airs Sunday Nov 21 on the History Channel. Good luck. :o

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It will probably suck.The show is good because of the personalities and chemistry of those three guys who host the show!:yesb:

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Originally Posted by Scott Harness

It will probably suck.The show is good because of the personalities and chemistry of those three guys who host the show!:yesb:

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Yep, I agree 100%. I saw the preview and don't think I will be part of there viewing audience. Another aspect I like about the original is the cars we don't get to see over here!

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Originally Posted by Scott Harness

It will probably suck.The show is good because of the personalities and chemistry of those three guys who host the show!:yesb:

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Originally Posted by Triathlete

Yep, I agree 100%. I saw the preview and don't think I will be part of there viewing audience. Another aspect I like about the original is the cars we don't get to see over here!

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All of these points are exactly how I feel about it. I do plan on giving it a chance, though.