Event details
- Date: Saturday, April 25, 2026
- Track: Buttonwillow Circuit
- Weather: Dry
- Official result: 86 Challenge Stock results
Stock top 5
| Pos. | Driver | Raw time | Adjusted time | Delta |
|---|---|---|---|---|
| 1 | Saurabh Kulkarni | 2:05.501 | 2:08.001 | — |
| 2 | Ivan Larionov | 2:05.822 | 2:08.322 | +0.321 |
| 3 | Brandon Stitt | 2:07.763 | 2:10.263 | +2.262 |
| 4 | Andy Leung | 2:11.168 | 2:13.668 | +5.667 |
| 5 | Yuriy Kovalchuk | 2:14.460 | 2:14.460 | +6.459 |
Fastest Lap Onboard
Summary
Well, the day has come. Out with SX2, in with the Yokohama V601s. These are fairly popular on both the street and track - a cheaper alternative to PS4S. First impressions on the street told me these tires are roughly as sticky and more predictable at their peak.
BW Circuit is all about maintaining speed through its long, sometimes cambered turns. The car was quite oversteery at this point, so it was easier to carry speed. Unfortunately, it was still Buttonwillow, so I had a limited window to get my fast lap in before sand and sun would ruin my bid. I needed to adapt to the new tires almost instantly to win.
A combination of having newer tires than Ivan and erring towards banking clean laps let me do a 2:05.5 in session 2 - enough to take P1 by 0.3s. I pretty much matched my SX2 PB despite bleeding time in a few places, which confirms my intuition that these tires are at least as fast as SX2 when in their window.
Lap Notes
T1: Lots of early yaw, had to pause rotation midcorner to avoid cutting curb. Stock bias should allow me to drag the brakes deeper without losing the rear.
T2: Braked too soft while turning, low braking efficiency/grip util on entry. Fronts bite pretty hard when you run into the camber, so it's tough when the car is oversteery with the rear bias.
T3: Soft on initial brake application - could have braked a bit later and focused the rotation more. Had to pause throttle application 3/4 of the way through because I didn't have enough rotation pre-apex.
T4: Overslow, didn't trust the engine braking. Ended up fake-tracking out on exit just to reduce tire heat.
T5: Need to carry a slightly more speed. Mainly be earlier on throttle but longer to full throttle. Camber is so extreme that the rear inside spins up easily. Just need to maintain speed for longer on exit until the car flattens a bit.
T6: Soft initial brake. Low grip util on entry. Not the end of the world, still learning these tires - I only had 2 opportunities to set a flyer.
T7: Pretty decent, slight boot-shaped release because I over sped but a bit of extra early throttle would have increased track usage & exit speed.
T8: Terrible, lost 0.4 here. car is just too oversteery on the brakes. 6 seconds of low tire util because I'm braking and turning for so long. Hoping stock brake bias prevents something like from happening again. Low braking efficiency also made me blow past the turn-in and acceleration point, requiring me to finish the rotation after getting on throttle. Really poor exit.
T9: Low brake aggression, but decent.
T10: Early/shallow turn-in. Had to lift to get the car back on the proper line. Lost 0.15 here.
Downloads
AIM XRK Data - Session 2Download
AIM CSV Data - Session 2Download