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Discussion Starter #1
I see ad's for some of the new cars and there are SUV's that are getting 260, 280, 300 horse power?
Are these all rear wheel hp numbers?
 

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These numbers are brake horsepower figures (at least most of them) Motor Trend and Automobile almost always measure in BHP, horepower at the rear/front wheels.

Yes, there really ARE SUVs with more horsepower AND torque than a same-year Mustang GT but think about the weight difference.
 

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It's still SAE net iirc... More or less the same method they switched to in '72. Flywheel, full accessories and such. I know of no car manufacturer that measures at the rear wheels, although there are some cars (LS1's) that severely underated and put down around what their net HP "should be" to the wheels.

Brake HP is a loose term... Another word for dyno is brake. Term is used too loosely IME to be counted on.
 

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Manufacturers use NET horsepower, not wheel HP.


Gross Horsepower: Absolute maximum horsepower at the flywheel, with no load or drag from auxiliary systems, such as the alternator, water pump, etc. Created in an ideal environment with precisely controlled intake and exhaust flow characteristics, this category is of little practical use.

Net Horsepower: Maximum horsepower at the flywheel, with intake and exhaust systems in place and accounting for load from auxiliary systems. This is what most automotive manufacturers publish as SAE net horsepower.

Wheel Horsepower: Measured on a chassis dyno, the maximum horsepower transferred to the ground by the drive wheels. It can be affected by gearing, with lower (numerically higher) gearing tending to indicate a lower torque peak. Considered the most practical measurement of usable horsepower.

 

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Well Clone, from your signature pic, it is a good thing I am not a big fan of cats. I am free to post away. /forums/images/icons/wink.gif
 
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Laughing my ass off at your kitten thing posted on your reply. That's great and I now know I must post a bunch of dumb questions to kill all the friggin' cats in the neighborhood.
 

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The newer ratings aren't measured at the wheels as some think. They are measured at the flywheel with all accesories attached to the engine, just like it would be when it sits in the car. Our HP ratings were made without the alternator, fan, power steering pumps, and what not all attatched. The HP ratings on our engines are slighty higher than what we would see if we measured the power output the way they measure the new engines power output.

I would imagine it only being about a 10% loss in power running an engine with accessories than without. But it also depends on how many accessories you have attached. Isn't this discussion fun?
 
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Perfect explanation - and accurate too. Wow, one of those cake and eat it deals.
Good job GT350clone!
 
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