Sharing my race experience at the RCI V3 Christmas Cup last weekend. The setup was based on Akio’s carpet basic setup.
I changed the rear springs from 2.65 to 2.7 and reduced the angle shim by 0.5mm, which slightly stiffened the rear support overall and made the car more stable through the high-speed corner at the end of the straight at RCI
I replaced the 5th screw on the motor mount with a set screw, and added 0.2mm to the ARS shim—aiming to boost rear-end rotation during on-power. The result was quite satisfying.
I adjusted the front downstop from 7.3mm to 7.2mm, which improved cornering steering. But I wasn’t fully satisfied with it in the end. Due to time constraints, I didn’t get the chance to test other spring setups.
I tested diff oil of 5k, 6k and 9k , and ultimately chose the 6k cSt . Most drivers in the same class opted for a thicker diff oil, but in my testing, it didn’t perform well with this car.
All the above adjustments are based on my personal understanding.