DNF: Finale (hopefully) - Back on the Road Again!

[t0ast]

Previously...
Part 1: https://opposite-lock.com/topic/13491/dnf
Part 2: https://opposite-lock.com/topic/17253/dnf-part-2-recall-failure-nsfe-ngine-pics-inside
... or TL;DR: My partner's FR-S blew up at autocross, likely due to the infamous valve spring recall "fix".

About 5 months after the initial, uh, incident... the SSC FR-S is back! Most of the wait was due to limited openings at our preferred indie garage, the decision to have the engine rebuilt instead of simply replaced, and those pandemic supply shortages and delays that we've all grown to love. The total cost wound up being a bit more than the indie's initial estimate due to some unexpected secondary damage (like a very crapped-up catalytic converter) and landed pretty close what the dealership was going to charge us originally. Even though that was unfortunate for our wallets, we at least have a mostly new engine instead of some random 60k mile old unit with an unknown history and the exact same recall issue to worry about.

After an initial break-in period, it was back to autocross duty with a double-header at our home venue. My partner and I were excited to not just have the car back in good working order, but to finally make use of some upgrades that had been sitting around since the start of the pandemic, namely new tires and data-logging tools.

Tires:
Originally, the SSC class started out with the Falken RT615K+ as its spec tire. They were appreciated to some extent for their affordability and durability, but they felt like the weakest part of the package. It's a B-tier pick at best compared to other 200TW tires and they have some mildly obnoxious characteristics to them. As of last year however, the class had moved on to the new and improved Falken RT660. This move was appreciated by most SSC competitors, as the new tire is a spiritual successor of sorts to the beloved but discontinued Bridgestone RE-71Rs. This of course means a shorter lifespan for each set of tires, but we now get to enjoy the performance benefits of current, competitive rubber.

The SSC FR-S originally came from D Street and went through a few sets of RE-71Rs in its time there, so we both settled into the RT660s pretty quickly. I'm not sure they entirely match the RE-71Rs, but they do come very close and were definitely more enjoyable to use than the 615Ks. They communicate better, the grip levels are substantially improved, they seem to have a larger operating temperature range, and they no longer fall off as sharply when you start to creep past their limits.

As good as they are, I'd be remiss to not also show off the hilariously rapid wear of the center tread after only 24 runs (at ~41 seconds apiece):

By most accounts, this is "normal" and the RE-71Rs did this too. Such is autocross life, I suppose

Data:
We were previously getting some data from a Garmin Virb Ultra 30's GPS and OBD2 readouts, but its usefulness in this application could only go so far. It lacked CAN support (so no steering or brake info), the GPS wasn't always accurate, and the most helpful info could only be pulled and compared after the event. It's been helpful, but after a few years of finishing near the top of the heap, we felt like we were ready for the next step. Enter SoloStorm and RaceCapture.

The setup we opted for here was SoloStorm's mid-tier RaceCapture/Track Package (at a little over $500). On the hardware side is the RaceCapture unit, which provides a gyro+accelerometer, a dedicated 10Hz GPS puck, and the ability to read both OBD2 and CAN data. SoloStorm handles the software side of things with an Android-based application. It manages the RaceCapture and camera(s), synchronizes their outputs, and creates informative comparisons between individual runs with minimal fuss. Running it on a phone is possible, but for better readability, we decided to go for an 8" Fire tablet and some nifty hardware from RAM Mounts to secure it to the passenger seat rail.

The main benefit of this setup is having accurate measurements for things like your inputs and car positioning instead of having to try and lean on your own subjective recollection and/or limited camera angles of previous runs. With about two hours of initial setup work and experimentation before the event, we came in ready to track our position, speed, throttle, steering, and brakes. This gave us a solid starting point to scrub through previous runs, see what worked or didn't, find the largest areas to improve, and see what behaviors behind the wheel were more effective.

Results:
Much better than expected! My partner and I both snagged top 10 PAX (class handicap adjusted) times out of ~75 entrants on both days. The best of those results put me in 2nd PAX / 3rd raw on day one, just a scant few PAX hundredths (and ~0.9s raw) behind the leader in an STU Evo that took 3rd in class at nationals earlier this month. Video of that run below:

We still need to reorient the accelerometer, figure out some good start/stop triggers (instead of doing it manually) and see if we can invert the steering angle numbers, but everything else worked surprisingly well from just our initial setup.

I couldn't quite follow up the act on day two with the course reversed, but finishing 5th PAX / 7th raw was more than satisfactory. I think there was roughly another 0.3-0.4s for me to find out there, but little mistakes here and there kept getting in the way of it. Data can only go so far, after all . We also had one other SSC driver show up for this one as well, who managed to stay ahead of me by ~0.1s on account of my best run (~0.1 ahead of theirs) getting coned away. That other SSC driver landed in the upper-mid rankings at this year's nationals, so being able to finish close to them on the 2nd outing with new tires made for some decent validation. Once again, video:

Overcooking my way into the offsets before the last turn is mostly what cost me on this one ... and I unfortunately don't have a video of the faster dirty run due to the Virb overheating for half the day

Probably the biggest tell of the data-logger's effectiveness was how quickly it helped my partner get back up to speed. We decided ahead of time that we'd stick to only one ride-along with each other then lean on SoloStorm for the rest. It was a bit of a gamble since they hadn't really autocrossed since the start of the pandemic (blown engine event notwithstanding) and have always learned best through muscle-memory from ride-alongs, but it worked out in the end. On day one the delta between us was ~0.9s, which was still good enough for for them to reach 5th PAX and raw, and that shrunk further to ~0.4s between our fastest dirty runs on day two (9th PAX / 11th raw).

Suffice to say we're looking forward to what remains of this season along with the next.

[AkursedX]

@t0ast

Good to see you guys are back in action!

I run the 660's on my Veloster N. This season I have run end-of-life RE71's, Kumho V730's, and Yokohama A052's as well. The RT660's are a solid second place. I feel the grip of the 660 is on par with the RE71 and it doesn't fall of temp-wise or heat-cycle-wise the way the RE71 did. It's lacking on overall grip from the A052, and the V730 can handle heat better than any other tire I've used.

I really need to drop the cash on Solostorm and a recording device. I use RaceChrono-Pro which does a decent job, but I like how Solostorm has a bigger user base and people upload their runs to the cloud at larger events.

Below is an example of RaceChrono-Pro. On the bolder line you can clearly see I'm well ahead before the left hand sweeper. I am out of the slalom .250s quick but I overshot the braking and pushed out which ended up costing me .416s over the rest of the run. I finished 3rd in PAX that event but would have won overall if I could have done both elements right on a single run.

[WhoIsTheLeader]

@t0ast

I thought this was shift knob mounted at first and was deeply, deeply confused. When you want to see just how many Gs your shifter pulls. . .

[Qaaaaa]

@t0ast Great that it's running again!

Another RT660 user here. Killer tire on a light car. I have them on my Golf, a friend has them on his AW11. Grip for daaaaaaaays.

[t0ast]

@akursedx said in DNF: Finale (hopefully) - Back on the Road Again!:

I feel the grip of the 660 is on par with the RE71 and it doesn't fall of temp-wise or heat-cycle-wise the way the RE71 did

That's roughly the impression that I got as well. It seems just about every bit as capable and didn't get as greasy with the heat (despite our efforts to try and figure out how hot is too hot), though they did feel a hair more vague at the limit. That also just might be my limited experience with the 660s and/or time since I last ran on the REs speaking though.

I also really still need to try something on A052s... for science.

Solostorm has a bigger user base and people upload their runs to the cloud at larger events

Oh yeah! Almost forgot about that feature. I need to go bug some of our other attendees to see if anyone else has been doing that.