13 Dec

Things are happening, they just aren’t real entertaining. Thanksgiving, shopping, and family stuff consumed much of the time, though a few car things did slip in.

I’m not convinced the alternator bracket is really fixed; even when tight, it’s possible to rock the alternator slightly, probably due to the mounting hole in the broken segment having elongated somewhat. It’s not entirely bad to redo it because it may have always been slightly out of alignment right from the start. A straight edge had been placed across the face of the crank pulley in order to determine the plane of where the alternator pulley needed to end up. What I didn’t check was whether the shoulder of the crank pulley and the alternator pulley were the same, not sure they are. As a result, the alternator may have always been slightly offset even before it broke.

In other news, over the last couple weeks, more test runs were made to better dial in the VE table, which was off a fair amount. Getting it closer to reality allows much better closed-loop air/fuel control, so that’s working pretty well now. (This was another task that the tuner was supposed to have handled, yet another I had to figure out on my own.)

Closed-loop boost control always looks like it can be better refined… tuning never ends. Boost has slowly been advanced to its current 250 kpa, or 22 psi. On ethanol there’s still no knock, and while boost at this level is fine for brief pulls, track events are probably a bit risky, as heat-soak may invoke knock. The ECU is configured to pull boost if incoming air temperature gets too high, and it’s also monitoring knock, but it’s still a concern. In addition, third gear is good for 120 mph, and while there’s no wheel spin, it’s getting close, so more power isn’t “necessary.” I’ll probably drop boost a bit for safety and reliability, at least for track events. Once everything is finally dialed in and working well with ethanol, Midlana may be switched back to gasoline for the street, just for practicality. Boost would be dropped to ~14-16 psi, but the chief benefit is that fuel mileage will increase by 50% (from ~20 mph to ~30 mpg).

Lastly, if you’re thinking of getting yourself a copy of the Midlana book, better hurry. The printer always runs discounts during the holidays, though the discount amounts seem to be somewhat random (they don’t inform authors what they’re planning), so it pays to check. Order now to get yours before Christmas!