After the detail-tuning to get the car running well on gas, it was switched back to E85 to confirm whether it’s still running fine on that – with its additional ~100 hp :). During the test drive, the car started idling about 100 rpm higher than commanded, so once back home the laptop was connected to see what was up. Hondas have a well-known problem where the ECU-controlled idle air valve (which gates air around the throttle plate to set idle speed) often gets sticky. It was a little surprising that that wasn’t the problem though, it was that the ECU was commanding the fast idle itself… why? Looking through the variables, attention focused on the idle deadband. The purpose of the deadband is to not overly “micro-manage” the idle, once it’s close enough to the target rpm, just let it be. Want to guess how wide the deadband was? Yup, +/-100 rpm, and as it was reduced, down came the fast idle. The deadband is now -100/+0 so we’ll see how it goes. It wasn’t a big deal, and I was glad that I could both diagnose the problem and fix it myself.
I pulled up to a light with a new BMW M6 behind me (570 hp but way over twice as heavy as Midlana). Normally I’m grown up and ignore taunts by other cars, but when the light turned green and I pulled away at normal speed, he was right on my butt. Oh, okay, just this once, and I romped on the gas with Midlana getting a bit sideways due to lighting up the tires in second. Third gear was better but still marginal, during which time the BMW got a lot smaller. Granted I didn’t signal to him when I was going to get on it, but didn’t really feel like he deserved one.
Anyhow, the to-do list is getting shorter: traction control and launch control.
Traction control: requires adding wheel speed sensors. Since I (still) haven’t swapped in the higher quality rod ends, it makes sense to add the sensors at the same time since the suspension has to come apart anyway.
Launch control/anti-lag: Launch control is used by turbo cars to build boost before leaving the starting line. This is done by imposing a low rpm limit (maybe about 5000) and retarding the timing. This extends the combustion burn cycle so late that the fuel is still burning as the exhaust valves open. The hot burning gases spin up the turbo which allows making full-power launches, but must be done sparingly since the hot exhaust gases are hard on both the exhaust and turbocharger. Regardless, it’ll be added because it’s there and because it’ll be fun to try out – heck, GTRs have it so it levels the playing field a bit. That said, it’ll hardly be used, partly due to the machine gun-like backfiring that occur which attracts all the wrong kind of attention. Still, it’s worth setting up to record at least one really fast 0-60 time and quarter mile should Midlana ever go drag racing.