Targa Miata
September 13, 2014 - Miatas at Mazda Raceway!
This is always a big event, but this year it was massive with the public reveal of the 2016 MX-5, a world record attempt, a showing of Racing The Rock under the stars and nearly 2000 cars. The paddock was mobbed and the track time was full.
It was also my first time to really let the new engine rip at sea level. I'm still in awe, it's a spectacular thing. Every time we got on the straight, I'd just power past every car in sight. Sure, it may not be as cool as catching a high power car in the corners and working out a clever way to get in front, but the big hammer is still pretty gratifying. Here's what it looked like from inside one of the other cars - I make an appearance at 2:00.

I was taking it a bit easy in the corners. Mostly because there's no prize for being the fastest at an event like this, and I did not want to crash. I was also backing off the throttle as I went over the crest halfway down the straight because the cars entering the next turn had no idea I was coming. With the closing speeds, I was essentially coming out of nowhere. This was a particular problem in the slower Group B, where I had one exciting moment as a Spec Miata moved over close to the wall as I came barreling up with about a 40 mph closing speed. I thought I was going to lose both door mirrors, one on him and one on the wall. The car was actually really well balanced, with a bit of inherent high speed understeer from the aero that could be counteracted with throttle.

The car, unfortunately, was not rock solid. When I had it down at Road Atlanta this spring for display purposes, it went into some sort of limp-home mode on me. I was never able to duplicate it and the car's been great ever since. Well, it started doing the same thing at Laguna Seca. I'd be powering along, and all of a sudden my drive-by-wire throttle would disable after a shift. It's not a fun experience, losing all power just when you're hitting the next gear. I found I could bring it back if I turned off the main battery switch, resetting the ECU. Of course, this wiped any error codes. Eventually, it failed on the way up the hill to the Corkscrew and I was able to coast back to the pits without resorting to the reset. It had to do with the electronic throttle.

Lots of theories bandied about and I tried to eliminate potential interference by wrapping the wiring harness, swapped out the pedal for another and generally got frustrated. It seemed to be heat related - and it alway happened on a shift. So eventually I just left it in fourth gear and avoided shifting all together. Still, I didn't trust the car so I parked it early. A bit of a letdown after the buildup to the event.

My current thinking is that I was hitting an airflow limit on the car's programming. There's one particular table that has to do with the amount of airflow expected for a given throttle opening, and I may have been exceeding it. That would explain why it's never been a problem with high altitude use, and why it happened when I was shifting and getting a big gulp of air when the throttle smacked open again. I'm going to mess with the table and see if I can duplicate the problem at altitude, then we'll see what happens next time it goes down to sea level again. Unfortunately, that probably won't be for another year, and I really don't want any questions around the car at that time. Some troubleshooting lies ahead.

Photo by Ben Sale. It's definitely not the classic Corkscrew shot, I love the different take on it.
entry 1130 - tags: MRLS, laguna