I wrote actually (and you quoted it):


"And the 4.6 M62 wasn't developed by Alpina, it was BMW's own work, sure on paper they're identical but I assure no one Alpina worker was officially involved in the developement of the 4.6is engine.

Alpina also used the 4.8 l version of M62 in the Z8 and E39 B10S (same bore as 4.6 but S62 crank), not N62."


So the part about B10 and B10S in your statement is redundant.

I talked to people, who was involved in developement of 4.6 M62 personally and they said, they had no interaction with Alpina at all, eventhough, as I also already said on paper the engines are almost identical.

That means a group of BMW engineers had a task to develope an engine for a heavy E53 as alternative to the S62, which was earlier considered to be the engine for the sporty version of E53, but "just doesn't feel right" (official quote) due to the less torque oriented characteristic. The new engine had to be more powerful than 4.4l, but the developement costs should be kept al low as possible.

So the BMW engineers team come up following solution - the 94 mm bore of the S62 was criticall (4 mm walls), and they come up with 93 mm bore, the supplier of the carnkshafts offered the 85 mm stroke crankshaft, which was less expensive as the lightweight forged S62 crank (B46 crank is 24 kg and like 1300 Euro and the S62 crank is 18 kg and 2000 Euro), so a copy of Aplina's B10 (M62B46) engine came from BMW without any official Aplina involvement.

Therefore, the 4.6l engine in BMW X5 has nothing to do with Alpina, being idetical to Alpina's 4.6l engine.