Major Softie wrote:Why do you feel you need a closed loop system for the street? If you have a mass air flow sensor, or (as you spec for your fantasy bike) an air pressure sensor, then the system is already responsive to elevation change.
Well (with apologies to George Mallory)...because it's there (and, I guess because it's MY fantasy).
The Mega/Micro-Squirt has some nice data-logging features. Feedback logged from a wide-band O2 sensor will give very precise information about the other sensors and the system performance. IOW, it's much cheaper than extensive dyno time and much more accurate than seat of the pants and reading spark plugs after throttle chops. The choice of a MAP sensor vs. a MAF sensor is a pragmatic one...MUCH easier integration into what is essentially an ITB set up with (or without) a common airbox...certain types of MAF sensors might work, but the MAP sensor has fewer drawbacks...(which probably wouldn't be much of a consideration if this were just a fantasy).
So far, a lot of people in this thread have talked about the ease of bolting parts to the bike, but the difficulty in making it work. Lambda feedback makes it much less of a stab in the dark. Sure, it could be removed from the system once the tuning is done...but, why? O2 sensors are removed from factory systems to avoid the ultra-lean EPA mapping...forcing the system to run in the slightly richer "limp home" mode...or, a black box is put between the O2 sensor and the brain to slightly alter the output voltage to trick the computer into a richer mixture. None of that applies to a ground-up, one-off, aftermarket system.
There are definitely two schools when it comes to aftermarket EFI systems. There's the keep it as simple as possible crowd (e.g., SDS-EFI...off the shelf "simple Digital System" with push button tuning)...and, then there's the let's do it because we can crowd (e.g., Mega/Micro squirt...open source, wide variety of options, technical skills required). I've been researching aftermarket EFIs for years and honestly feel that both camps end up putting forth the same amount of effort...simple isn't always simple.
The reality is that carbs work very well on an airhead...one would have to border on insane to consider EFI
