Context available here.

MPH, 2020 vs. 2018

This is the GPS signal from the databox. We collect data more frequently now, so I had to ‘expand’ the 2018 trace to fit the timescale. We should try to use the same settings to make lining things up easier. 🙂

Note that the Nano seems to have died partway through the final run… all I had were zeros after that. You see the purple line just stop in the middle of its plateau. Also! You can see the lower gearing working, at least ’til the engine runs out of power.

MAP, 2020 vs. 2018

These are absolute manifold pressure values. They come from the databox, which is using a different style of MAP sensor than the ECU does. We should use the same damn sensor. 🙂 Can you tell which line is 2018?

Our cranked-up boost knob on Thursday (green line) was looking good at the beginning. We also lost that signal from the databox when the Nano stopped. You can see the ECU’s MAP numbers in the next graph, though. Not pretty.

ECU Map Vs. RPM, 2018-Final vs. 2020-Final

We changed the RPM at which logging starts, so the 2020 run starts ‘earlier’. We should try to use the same settings to make lining things up easier. 🙂

The two top lines are MAP, the two bottom lines are RPM. You can see the shift points in the MAP values of the 2018 line, but the 2020 MAP line is just … blah.

Timeslips

Run 1: Saturday, August 8th, 4:08 p.m.

Unpacked! Tech’d! Ran! but rpms were low, for good reason.

Run 2: Sunday, August 9th, 3:40 p.m.

Tach fixed, qualified! in two miles, #4 and #5. Went straight to Impound.

Speed seemed low, though. And the roof rails seemed high, according to the TechInspectors. The rails disqualified our run, and we went back to the pits for thinkin’.

The data showed a tiny speed trend upward throughout.

Run 3: Monday, August 10th, 1:08 p.m.

Qualified again, this time without roof rails.
Review of the data showed some good boost in the lower gears, but nuthin’ much happening in fourth or fifth gear. Spent some time talking about rev limits and shift points, and made a small tweak to the fueling around 8,800 rpm to try to help the engine get on the pipe.

A disturbing pattern emerged; mile four was only slightly faster than 3, and mile five was slower than 4.

Run 4: Tuesday, August 11th, 8:58 a.m.

We were in Impound from Monday’s run. We tried to start the engine to warm it up before towing out, but barely got a ‘pop’. In desperation, we decided to bump-start the car during the tow.

That worked, thank goodness. We were far back in the line at the start, as we’d delayed getting out of impound. With the engine running since the tow, the water temp was getting a bit high. We shut off the engine, figuring that we could bump-start it again at the line if necessary. But, warm now, the engine restarted when it needed to.

The run only went through Mile 4 ’cause that was the mile in which we qualified Monday. However, it was too slow to set a record.

Run 5: Wednesday, August 12th, 4:35 p.m.

After six or so attempts to get the intake valve clearances set, we had reasonable compression in the motor. Everything else was ready, and mile #4 qualified!

The overall pattern, though, was the same as the previous days; speed peaked in mile four, then slowed down thereafter. Checked the compression in Impound, and it was about the same as before the run. Where is the speed?

Found water on the floor of the cabin, and identified a crack in the coolant water tank behind the driver. N.B. epoxy sets up quick when the outside temp is near 100F.

Run 6: Thursday, August 13th, 8:04 a.m.

We were in Impound from Wednesday’s run. The water tank patch held overnight. Just before we towed out, Tom gave the Boost Control knob one full twist in the ‘+’ direction.  Later the ECU data from the MAP said boost was approximately 4psi higher than it had been.

We didn’t have to bump-start the car (though we feared we would).

The gear ‘slip/catch’ which had been present in 2nd gear now appeared in 1st gear as well. The car had good speed at the 2 1/4 mark, but struggled so much that the driver felt it hadn’t made the record; he was surprised to hear it worked.

The run only went through Mile 4 ’cause that was the mile in which we qualified Wednesday. Record set!