About the car's horsepower

We can see the car info in the show room.
But the Ultima GTR Road only display as 626hp. It should be 720hp.
And other cars also have less hp than what they should have.

So why? Maybe I miss someting?

 

AMS measures HP from the wheel so you have to tack on something like 15% to get a rough BHP estimate.

 

Thanks! Got it.