Originally Posted by Soccerluvr4
We all know manufacturer "claims" aren't always the most accurate.
Actually manufacturer crank hp claims are very accurate (though often understated) and the BEST thing out there. They test the engines at the crank with fewer variables in the mix.
Or I guess you'd prefer a dyno at your local shop over what a manufacturer says.
Manufacturers have billions of $ of R&D. They know how to test hp at the crank very accurately. On top of that, they have complex computer simulations of everything that lets them know in advance before even building an engine what its going to make.
So when Ford says their engines make 420 hp. You'd better believer that their engines can & will make that even in some of the worst situations (high altitude, high heat, etc.)
Obviously, there's going to be some variations in engines/break ins/ etc., so some might have a little less friction thus generate more power here or there. but for the most part the engines are probably making 425hp +- 6hp.
Once, you add in the variables or transmission, driveshaft, rear diff/gears, wheels, etc... you're going to see a lot more variation on the final output at a dyno.
Maybe what you mean is manufacturer's don't tweak / tune out the most performance out of cars?