GRX: alpha test 1

Today, I took the GRX (Generic Racecar Experiment, 2007 Toyota Yaris) for a test-n-tune day at Thunderhill West with Ace Robey’s Exclusive Track Days (which despite the name is rather inclusive). I had 2 goals for the day (1) test the RaceCapture telemetry device (2) learn how to drive the Yaris more aggressively.

The RaceCapture is a tiny device that you plug into your OBD2 connector. It draws power from there and then broadcasts telemetry data over a Wifi signal. It reads various car sensors over CAN bus and has high resolution GPS and accelerometers on board. It’s not available to the public just yet. I got my unit early as part of the beta test group. There are some bugs to work through, but it’s clear it’s going to be the most bang for the buck in racecar telemetry.



A B-Spec Yaris doesn’t really have much you can tune. There’s tire pressures and that’s about it. So the test-n-tune day was more about testing and tuning the driver than the car. I did a little research on B-Spec lap records, and they tend to lag Spec Miata by +6-8%. That is, if a Spec Miata can do a lap in 100 seconds (1:40) a B-Spec would take 106 to 108 (1:46-1:48). My mostly-stock Miata on 200 treadwear tires tends to run about 5-7% off SM pace. So I need to get my Yaris times close to my Miata times. No rush though since I am aiming for the 2018 SCCA Runoffs. I have about 2 years to get my driving to the National level.

The day started with rain, which was a little unexpected for early October in Northern California. The initial rain after a long dry spell tends to be extra slippery because of the oils rising off the pavement. As advertised it got very slick. Most of the cars decided to park, but some of us stayed out and had a great time.

In the second session, the track was drying, but I was fiddling around with the RaceCapture and missed most of it. I decided to put it away and work on my driving the rest of the day.

Session 3 was just before lunch. The track was now completely dry and the weather was perfect for lapping. I looked at my lap timer mid-session and was surprised to see 1:34.1. I was hoping to break into the 1:35s and there I was knocking on the door of 1:33. In the last lap of the session, I got a great drive out of the last corner but fumbled the upshift. Crap. Another 1:34.1.

I had a light lunch and then when back out with the rest of the open passing group. Everyone was behaving themselves really well, and I was able to find some space for a few flyers. I got a couple more 1:34.1s and then tried a new line through T1. Driving the Yaris is different from the Miata, and I’m learning the nuances. It’s not just FWD vs. RWD. One difference is that the Yaris is geared tall with huge spaces between gears. It’s ANNOYING! But I’m adapting. And I threw down a 1:33.7. When I checked the timer and saw the time, I literally screamed all the way through T1. I don’t have that on video because the damn 12V adapter kept falling out. Thankfully there was a track photographer.


So how does a 1:33.7 at Thunderhill West compare with my Miata? About 1 second off. Not bad. Not bad at all.

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