"WRXforScience" (WRXforScience)
01/21/2020 at 12:30 • Filed to: Track Day, BRZ
2
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"WRXforScience" (WRXforScience)
01/21/2020 at 12:30 • Filed to: Track Day, BRZ | 2
| 6 |
One of my goals for 2020 is to continue to improve as a driver and the easiest metric for improvement is lap times, so I want to set new person best (PB from here on out). For the second Saturday in a row I’ve been able to set new PB’s (at different tracks).
This Saturday’s event was at Eagles Canyon Raceway which was completely rebuilt last year. The track had been bought by new owners who are true enthusiasts and who wanted to make the track as good as it could get. This meant completely rebuilding the racing surface and altering the track layout. They had a good plan but the weather decided to throw them a curve with the wettest couple of months on record followed by cooler and wetter weather than we’d seen in decades. They just needed a week of dry weather with temperatures above 70F, which in Texas usually isn’t a problem. The track could have reopened as early as October of 2018 but didn’t until September of 2019.
Since the track hasn’t been open long and I’ve only got a handful of days on the new configuration, setting new PB’s there is easier than at the other local track where I’ve done more than half of all my trackdays. To top it off, I needed to retire a set of RE71r’s that I use for autox (I’ve had a new set ready for over a year but since I’ve transitioned from autox to trackdays as my main motorsports outlet it took way longer to wear them out than in the past). Now, both the Hankook RS4 and Bridgestone RE71r are 200tw ‘street’ tires but the stones are much softer and stickier than the RS4's (the RE71r’s are closer to a 100tw tire than a 200tw, while the RS4 is a sticky 200tw). I wasn’t sure if my heat cycled and mostly worn RE71r’s would be faster and there was a distinct possibility that they wouldn’t last the day so I brought my RS4's just in case.
One of the benefits of my BRZ is that it’ll easily fit a set of tires and tools with the seats folded, so bringing an extra set of tires wasn’t a hassle. However, my 10 year old Harbor Freight aluminum floor jack died on me when I was swapping wheels on Wednesday (I got a replacement before Saturday’s trackday and I had a scissor jack that I used to swap tires but it was a bit annoying to just have a tool not work).
The track surface is in great shape; however, there isn’t much grass and the week before the trackday they got 4" of rain followed by 2-3" of snow (very rare for this part of Texas) so the runoff areas were a swamp. The track workers had spent considerable time and effort to clean off the track during the week, the topsoil from one of the hillsides migrated onto the track and had to be cleaned. The surface was damp but clean when we started Saturday (it rained again Friday), temperatures were in the 40's but the track dried quickly and by the second sessions conditions were great. Any car that dropped so much as a single wheel was required to immediately stop and was put on a flatbed to keep the clay from getting spread all over the track (one of the workers had to be winched out of the clay earlier in the week when he sank in past his knees while walking out to one of the corner stations, his boots were lost to the muck).
A couple of the morning sessions were cut short due to cars going off track and the rule that all off track cars had to be towed in (most of the cars could have made it in under their own power but they would have spread enough slick mud and clay on the track to guarantee more off track excursions). By the afternoon sessions everyone had figured out how to stay on track and conditions were perfect for setting times (aside from traffic). I’ve been running the Novice classroom instruction, so I miss out on running with the other instructors in the instructor run group (that’s when the novice class is) and at Saturday’s event I was also doing in-car instruction with one of the novices (in an Audi R8 v10!), so I had to either rush to grid late for the “Advanced” group and/or run with the “Intermediate” group. I tried both.
One of the biggest perks of instructing is that you can run in any run group as long as you don’t miss any of your coaching duties. I took advantage since I had tires to burn through. I ended up running in all 4 Intermediate sessions and 3 of the 4 Advanced sessions (the first advanced session was a single lap and I gave a ride to my Novice student in another, but I got plenty of track time).
The “H oosier-stones” were definitely worn but they had at least as much grip as my fresh RS4's (braking data showed the same maximum braking force but lateral grip might have been slightly better on the RE71r’s). Running the Bridgestones at the track feels a bit like cheating and I avoid using them for track work since they wear very quickly and have a tendency to overheat with hard track use. Mine were heat cycled which kept them from overheating (and made them useless for autox). This new PB has a bit of an asterisk for me, I don’t know for sure the tires were completely responsible for the time I found but I’m pretty sure they helped. I’ll just need to match the time on the RS4's (or improve it) to remove all doubt.
Distraxi's idea of perfection is a Jagroen
> WRXforScience
01/21/2020 at 12:55 |
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“ braking data showed the same maximum braking force”
What do you use for a data logger?
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WRXforScience
> Distraxi's idea of perfection is a Jagroen
01/21/2020 at 13:31 |
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I’ve got an AIM Solo2 I get the brake force from the longitudinal g-forces.
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Distraxi's idea of perfection is a Jagroen
> WRXforScience
01/21/2020 at 21:57 |
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How do you find it? I’m using a cellphone based one (Harry’s lap timer). It’s fine for lap times and splits but its acceleration and track position estimates are only really useful for entertainment value. Thinking about going to something more useful but don’t want to invest in a proper wired-in one like I had in the Commodore.
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WRXforScience
> Distraxi's idea of perfection is a Jagroen
01/21/2020 at 22:14 |
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I exchange data with some friends and really like the real-time led display that tells me if I’m faster or slower. The data analysis afterwards is informative but takes a bit of learning to figure out and make useful. The unit is much more accurate and reliable th an any of the phone based setups (the AIM uses a 10Hz gps whereas phones are 1Hz).
It was a bit expensive upfront, but with actual data you can learn when and where you’re losing or gaining time and make better use of your track time and eliminate any guesswork. They aren’t necessary when you’re first starting out, but once you’ve found all the big chunks of time they really help you find the tenths here and there.
I’ve got a bluetooth OBDII reader that syncs with my camera and gives me all the OBDII data, you can get the “DL” version that has a OBDII hookup to get you all the car data you want. The DL version is like $200 more than the standard version so you’d have to decide if the ECU data is worth that.
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Distraxi's idea of perfection is a Jagroen
> WRXforScience
01/21/2020 at 22:29 |
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“ They aren’t necessary when you’re first starting out, but once you’ve found all the big chunks of time they really help you find the tenths here and there.”
That’s pretty much where I’ve got to with the 86, after a couple of years with it. Took me a while to relearn driving a momentum car after 5 years in a “ get it straight and light the fuse” one, but I’m now at the point where I’m not getting better but it feels like there’s a bit more on the table. The phone’s not informative enough to help with that
The Commodore had an old but insanely expensive (thanks, PO) Vbox setup with sensors all over and accurate-to-centimeters differential GPS . It was a PITA to use, but totally convinced me of the value of data to take you to the next level.
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WRXforScience
> Distraxi's idea of perfection is a Jagroen
01/21/2020 at 23:01 |
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Sounds like you’d benefit from an AIM then, especially if you know or find other local guys to exchange data with. You can learn a lot from your own data but being able to compare with others really helps find those eureka moments and places where you’re losing time.
I get more out of my AIM data than I do out of videos as far as finding places to improve. I’d recommend the Solo2, but if you want the ecu data and don’t already have a way to capture it, the DL is a convenient package. I don’t know that I’d be able to justify the cost of the Solo2 DL, but there are plenty of the older Solo DL’s floating around and you can sometimes find great deals from people upgrading.
I had to spend a good 4 hours watching youtube tutorials to learn how to set up and do all the data analysis, but once you learn how to do what you want, actually interpreting the data from a session/day is very quick and easy (10-15min and you can get all the information from the data you need/want from an entire day, you could look at it between sessions and definitely during the lunch break.
The main upgrade that the Solo2 has over the old Solo is the 2 has led lights that you can configure to tell you if you’re going faster or slower (like a predictive lap or section timer but continuously updating in real time). I’ve got mine set up so that each light is a tenth (there are 5 of them), green lights are faster by a tenth each and red lights are slower by a tenth each. If I try a different line I can immediately tell if it was faster or slower and by how much (that’s really all the data I personally need while I’m at the track, I don’t want to overthink my driving while I’m at the track).