Originally Posted by ozinaldo
Just to clarify, in my case the altitude was like 500 m. above sea level, not too high to make a serious difference, which shouldn't contribute anything more than a single hp or two to the 29-30 whp difference between a M3 and 1M on the same dyno.
I think the predominant reason for the manufacturer is always to position the car vs its other brand competitors plus also to rank it vs other inhouse relevant models, so they "round" and "polish" everything a bit, as long as it fits the purpose. Who is gonna prove it otherwise and if they do there will always be scientific justifications (read "conditions")
Could be more than 1 or 2 whp with that altitude.
Agree with the commentary that there is a desire to slot the car carefully within any given lineup....that factor can always lead to fudging. In an E60 550i, the V8 is claimed to be what, 360 horsepower? The N54 in the 535 needs
to make 300.