Quote:
Originally Posted by Pete_vB
Again, all of the above is easy and cheap; you're simply roughly doubling the motor honda made 10+ years ago with the S2000, or increasing the bore and reducing the stoke of the V8 M3. No peaks, not terrible fuel economy, etc- all well understood. And from a technical point of view pretty boring.
What's tricky, and what's out of the experience base of most here, is an appreciation of efficiency and brake specific fuel consumption. I've attached a map of a turbo diesel motor; this is basically a map of how much power a motor produces for a given amount of fuel, with lower numbers (grey) being better.
Normally aspirated motors can have reasonably high BSFC in one area of the chart, but fuel consumption increases dramatically to either side. As a motor rarely runs in the "sweet spot" (wide open throttle @1800 RPM in the chart below) they rarely if ever achieve the efficiency they are capable of. Much of the fuel is wasted simply overcoming the friction of the spinning motor.
Turbos tend to have much wider peaks in maps like the below, allowing them to average much more energy per unit fuel. For those that understand engine technology the choice is clear- for a given amount of CO2/ fuel you can choose NA, or you can choose FI and make around 25% more power. Regulations have forced BMW to be concerned with fuel economy (if rising fuel prices hadn't already already), and hence they have no choice but to move towards FI, Luddites be damned. For a given amount of emissions/ fuel it simply allows them to deliver much more power. I'm sure they would prefer not to; it will result in more complex motors, where it sounds like simply raising the redline is enough to keep the "fans" happy. However they will also be more modern, advanced and to my eyes better motors. If they do it right, which is what the real question is in my mind. If they skimp and figure they can make their power targets without putting their best foot forwards I think they will get the message loud and clear, and M3 sales have already been slipping.
Another point- many here think "race" motors should be normally aspirated, but that's a view highly skewed by marketing. F1 will soon return to FI, following drag cars, WRC, the turbo cars of Group C (also concerned with fuel economy; the C stands for consumption) and indeed most race cars this side of carburetted nascar. A good FI motor can be very, very good; much higher power to weight ratio vs NA, more torque, better economy, etc. BMW has some of the best engine designers in the world- again I look forward to seeing what they come up with it the engineers are given free reign.
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I love NA, but I am afraid what you say above is true... In other words the FI route is inevitable.
I only hope the end result will be better in all respects, without compromising throtle response, overheating and/or component reliability (as a result of a more complex system).
The high reving feeling & what comes with it such as the sound of a screaming NA engine will most definitely be gone - hopefully these will be the only casualties. I don't know, maybe who cares....