Copied from this months EVO.
Sorry i didn't scan it, my scanners not working at the moment, but I think its a very interesting articel so had to put it up
POWER OF M
The M5's all-new V10 engine promises to be very special indeed. Jeff Daniels looks inside
"We're looking at the tour de force here. More specifically, we're looking at a 5-litre V10 with an output of 500bhp. That's naturally aspirated of course. BMW doesen't like turbocharging, except for diesels. So, for the required output of 500bhp, BMW needed a 5-litre engine which in turn dictated a V10. Not a V8 because the cylinders would have been too big - BMW likes the idea of 500cc per pot - and not a V12 because all other things being equal, a V10 is shorter, stiffer and has usually fewer internal power losses than a V12, which is why today's best F1 engines are V10. At the same time, a V10 has more piston area than a V8, making it easier to achieve specific output power so long as you design the engine to withstand being revved. The new V10 (official designation S85) peaks at 7700rpm with a red line at 8200rpm.
The alloy-blocked S85 is a 90-degree engine. Forget all you heard about 72 degrees being the mechanical balance ideal for a V10 (being one-fifth of 360 degrees). It is, but acording to BMW, when you have this many cylinders, and so long as you get everything else right, it dosen't matter. The V10 doesen't have balancer shafts. It doesen't have clever engine mounts. Apparently it's smooth enough. What else? Forget spreading the inlet and exhasut valves wide apart for maximum valve area and optimum output. The V10 valves have just 23 degrees between them (13 degrees on the inlet side and 11 on the exhaust). It creates a package that will actually fit the 5 series engine bay, and the valves are plenty big enough because this is a big bore engine - 92mm bore, only 75.2mm stroke for an actual capacity of 4999cc) and the gas flow at high speed is strong because there is no nonsense here about asymmetric ports with high swirl and control valves. Each pair of ports is mirror-image identical and finish machined, and the hell with the expense. It's no recipe for a low torque peak and sure enough, the 520Nm (383lb ft) peak falls at 6100rpm. The inlet camshafts are chain driven, the exhasut camshafts by bevel scissor gear from the inlets. All four camshafts carry VANOS variable valve timing actuators, with a new higher pressure hydraulic system for faster response.
The short stroke ensures the mean piston speed is barely more than that of the old M5 V8 (20.7m/sec at 8200rpm, if you are a purist). That old engine, of more or less the same capacity, delivered "only" 400bhp at 6600rpm. At 240kg fully dressed, the V10 weighs within spitting distance of the V8.
A contribution to the high output comes from a 12:1 compression ratio which in turn calls for some special knock protection. The S85 is the first engine to be equipped with a "full house" in-cylinder ionisation detector system, using the spark plug as sensor. It can pick up both misfire and any danger of detonation, cylinder by cylinder. All of this is just one aspect of the engine's highly sophisticated electronics. Everything is optimised for crisp response, one of the main factors behind BMW's dislike of turbocharging for spark ignition engines.
A lot of the electronics, needless to say is bound up with the fuel injection system. The actual induction is interesting: two big plenum chambers conceal the ten short intake trumpets, five per side, with the individual drive by wire throttle butterflies. here again it's never mind the expense: individual valves give the best perfromance (in particular the best repsponse) so there they are, even if it means fitting ten individual idel speed control valves.
Everywhere you look there are interesting but complex (and hence expensive) features. You could go on and on about this engine, but i think you get the picture. It's going to be great."
Power/Torque Graph i found:
taken from
HERE
EVO - E60 M5 V10 article
Linear Mode
