Wait, what?!?!? BMW may RETHINK their engine line-up, in particular the ///M engine?

[GUINNESS]

http://www.youtube.com/watch?v=WdL35uvySpc&feature=dir

Go right to 1:30. The company is CONSIDERING going FI in the ///M cars. None of this is definite, but still. Just wow.

[LeMansX5]

You mean this?
http://www.xoutpost.com/lounge/45145-...l-engines.html

[FSETH]

Good call LeMansX5, I missed your thread so I will add mine here.

I think BMW has to consider FI not only for higher fuel economy numbers, but mainly because the new bi-turbo, non-M cars are so strong. They have really closed the gap between the basic cars and the M-cars.

[Dblock2151]

Originally Posted by FSETH

Good call LeMansX5, I missed your thread so I will add mine here.

I think BMW has to consider FI not only for higher fuel economy numbers, but mainly because the new bi-turbo, non-M cars are so strong. They have really closed the gap between the basic cars and the M-cars.

I hope they don't go FI, that's the main thing I respect most about ///M cars.

[JCL]

Originally Posted by Dblock2151

I hope they don't go FI, that's the main thing I respect most about ///M cars.

I don't get it. Would the M models get even more respect if they had pushrods? Carburetors? Points and condensors?

I understand not respecting a poorly engineered FI engine, one with lag and poor throttle response. But a well-engineered FI engine (like the 3.0tt), is that somehow less of an engine than a well-engineered NA engine?

[vinuneuro]

Originally Posted by JCL

I don't get it. Would the M models get even more respect if they had pushrods? Carburetors? Points and condensors?

I understand not respecting a poorly engineered FI engine, one with lag and poor throttle response. But a well-engineered FI engine (like the 3.0tt), is that somehow less of an engine than a well-engineered NA engine?

Variable Geometery Turbo's allow engine makers to have the best of both worlds, creating perfect powerbands. There's no reason not to use them. The M engines can be just as responsive as they are now, as individual throttle bodies can still be used.

[vinuneuro]

What BMW needs to do with M V8's is to start using cross-plane crankshafts.

[JCL]

Originally Posted by vinuneuro

What BMW needs to do with M V8's is to start using cross-plane crankshafts.

Wouldn't they be moving ahead if they used flat-plane crankshafts? Narrower cylinder angles, higher-revving.

[vinuneuro]

Originally Posted by JCL

Wouldn't they be moving ahead if they used flat-plane crankshafts? Narrower cylinder angles, higher-revving.

Sorry, I typo'd. I meant to say that they should move away from the cross-plane design.

These M engines are supposed to be about maximum performance, so I don't understand why they used a cross-plane design. Reducing the counter-weight size would do wonders for engine response, and it's also proven that a lighter rotating assembly yields greater power/tq as the rpm go up. And let's no forget about the packaging and performance benefits of a more compact crankcase that a flat-plane design allows.

If the 4.0L V8 used a flat-plane crank design, it probably wouldn't even need balance-shafts to counter the second-order vibration. Usually 2.0L is the cut-off for 4cyl's, and a V8 produces only 41% more second-order vibration.

The Formula One V8 most certainly uses a flat-plane crank. Why not the M3?

[GUINNESS]

I realized that was the thread after I had posted this one... no mention of ///M in the thread title, no care