Crank ⇄ wheel hp calculatorAn honest estimate, not a promise

How big is the loss really?

There is no single number. The gearbox, differential and tyres all turn some power into heat, and dynos and weather correction differ too. Three real examples from our guides:

• Nissan GT-R R35: Nissan rates the 2017 US car at 565 hp, and Cobb measured a stock one at 501 whp, about 11% lower (guide).
• Mercedes-AMG C63 S: RENNtech quotes 601 hp at the engine and 517 whp, assuming a 14% loss (guide).
• Litchfield's LM1000 GT-R: 1,047 bhp at the engine and 824 at the wheels, about 21% lower.

So treat the result as a range, and compare tunes on the same dyno. More in Crank hp or wheel hp?

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