We are working down the list of issues and sorting fueling on the D1 is very high on that list. Rodney has made several runs with virtually no power and still managed to post respectable times. This speaks to the capabilities of the driver and the chassis, but power is the missing ingredient. In order to get things sorted we needed a wideband O2 sensor and yesterday Morgan picked it up. Ray and Chris installed it and I finished up the wiring.
The AFR gage replaced the still unused boost controller in the dash.
The basic issue is that if we set the pressure sensor voltage for the altitude then it starts and idles but won’t rev. If we set it for what the ECU was tuned at, it revs but won’t idle or even run under 4K RPM and is nearly impossible to start. What we need to do is remove fuel when the engine is not on boost, but we can’t do it blindly and the O2 sensor will let us do that. If we can actually get the car up the Mountain to log the data we need. So as a temporary fix I made a switch that selects between a start/idle voltage set by a pair of resistors and the adjustable run/power one set by a potentiometer.
That being the last task of the day we packed up and got a bit of sleep. Up at 2AM this time to try and get a better parking spot at Glen Cove. A lot of other teams had the same idea but we did OK.
Jonathan has been wanting to try a run on hot tires and we’ve been fortunate to get our hands on a set of tire warmers. It took a bit to figure out all the logistics but once that was done we were all set.
This being a short section we skipped the first run. Jonathan went up in the second one, and Rodney followed.
The two had very different goals for the run. Jonathan wanted to make sure he can have confidence in the car when it’s all up to speed and up to temp. Hard to do on a short, cold run so the tire warmers were the big test – and they paid off with a good run and a quick time.
Rodney’s goal was to complete at least one run on this section which he has to do as a rookie, and to gather data for the engine tuning. To do that he had to pull up to the start line in ‘pit’ mode, then launch and shift to ‘race’ mode with the switch. To complicate things we are still running with a compromised shifter (the replacement parts for the valve block are being overnighted from Canada for delivery later this morning). The transfer between modes was not as smooth as we had hoped and he spent what seemed like forever at near-walking speed trying to get the engine to kick in. Eventually it did and he sounded good going up. Shortly we get confirmation he finished – whew. One step closer to the race.
The encouraging thing is that above 4K RPM the AFR is excellent, so we just need to remap the area below that – which is only used to start and in a couple really tight hairpins. But you have to be able to start in order to run.
Both cars made one more run and then we packed up. Lots of work still ahead, most of it on the D1. For the D2 we’re just awaiting delivery of the tires we’re going to use in the race. The plan is to go to Pikes Peak International Raceway later in the day where we can do the work, scrub in the new tires, and do some basic testing. It’s a full day ahead and may spill into tomorrow as well. Sunday we race.