Solo Spec Coupe vs Stock

Had an interesting and somewhat unique opportunity today - I drove my stock Scion FR-S against a fully prepped Solo Spec Coupe FR-S, both on the same tire. We also switched cars for two runs.

For the uninitiated: in 2017 SCCA introduced the first ever spec autocross class. Based on the 2013-2016 Scion FR-S and Subaru BRZ, SSC brought spec racing to autocross by requiring drivers to modify these cars with a spec kit and limiting other modifications with fairly strict rules. The kit includes sealed Koni yellow shocks, Eibach lowering springs, front and rear swaybar, and an alignment kit. All cars run 225 width, 200TW Falken Azenis RT615K+ tires on 17 x 8 wheels with a minimum 17 lb weight.

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These tires are the most controversial part of SSC, though ‘controversy’ is a bit of a stretch - they just aren’t amazing. Certainly good tires, far better than any all season and most ‘normal’ summer tires, but definitely lacking the grip and responsiveness of current autocross leading tires like the Bridgestone RE-71R, aka ‘hoosier stones’.

The tire is the rare part of this back to back comparison test. As my car is stock, it runs in DS. In DS tires are open to any 200TW compound. To be competitive I should really be on a better tire, but as I wasn’t sure when I might convert to SSC I bought SSC tires.

Thus it truly became a test of suspension mods, and as we both drove both cars driver ability was equalized. The SSC owner has more autocross experience and I would be pretty confident in saying he’s at a higher skill level than I am, though to my own credit I’m not that far off.

So what happened, and what did I think of the cars back to back?

On a very fast course, he set a 47.6 to my 48.6 in our own cars. We switched for two runs, and both of us messed up and accidentally left traction control on for one. His first run in my car was a 48.8, mine in his was a 47.7. He managed a 48.2 on the second run in spite of traction control, while I got slower due to that distraction.

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It would seem, at least on this day, that SSC suspension is worth .5 to 1 seconds on a ~50 second course. At this event we run the course in the opposite direction in the afternoon, and I somehow managed to rip off a 46.8 second run in my stock car to his 46.4 in his SSC car.

Generally speaking, the impact of the kit was pretty noticeable. Turn in is almost violently quick - literally feels like driving a go kart. The whole car felt more stable, as mine is pretty tail happy in its current state. That being said, it’s not like the suspension mods are an easy button to speed. Overall the drive felt very similar, requiring the same level of maintaining momentum, planning ahead, and controlling oversteer. It’s just that the SSC car could enter a few elements faster, hold its line better, and, I think most importantly today, put power down out of tight elements much more securely.

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The SSC owner said my car had a very loose rear end - the loosest he’s felt since his old Miata of which Bman currently owns and I have driven.

The only other noteworthy difference between the two cars was his application of Hawk HPS brake pads. I haven’t yet upgraded from stock, but that’s going to happen sometime next month because holy crap are those pads so much better than stock. I don’t think the brake compound alone created .5 seconds of time, but it would certainly help me close that gap a little more.

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All in all the experience really points to how fantastic this platform is. More on that to come soon as I’ve had a review in work that I’ll post later today or tomorrow. 

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