Stolen from last year's release notes:
The cars are more than just mirror images of each other. The Cup car is left hand drive, and uses the 6-speed transmission available in the production car. The Roadster is based more closely on the Japanese-spec NR-A version, with it’s 5-speed transmission and slightly smaller tires.
This may seem like a mis-match, but it’s closer than you may think. With the different gearing, the Roadster loses a little bit in straight line acceleration, due to the bigger RPM drops between shifts, but partly makes up for it with a better top (5th) gear ratio compared to 6th in the Cup car. That’s not even mentioning the right hand weight bias that can prove beneficial on the predominantly clockwise-run road racing tracks. However, the Cup car does have a potentially higher top speed (in the draft) on the longer tracks.
- Gearing and setups are the big difference between the two. Gearsets are below:
Cup Roadster
1st: 3.82 3.136
2nd: 2.26 1.888
3rd: 1.64 1.330
4th: 1.18 1.000
5th: 1.00 0.814
6th: 0.79
Final Drive: 4.10
- Both cars are going to be fixed setup for Novice level races, so that takes a lot of the “tinkering” out of the equation. Advanced level events in both cars will allow standard adjustment of alignments (Caster, Camber and Toe) along with tire pressures. The Cup car will allow shock damping adjustments as well as limited ride height variation.
- Roadster has Bilstein (non-adjustable) dampers and stiffer springs than standard production, but not too stiff for daily use. (A good number of the racers that run the car at Tsukuba Raceway drive the cars to and from the track, and even commute in them.)
- Cup car has Sachs 2-way adjustable dampers (Bump and Rebound) and are quite similar to the Mustang shocks in their damping adjustment method. Bump is adjusted in “clicks” while rebound is modified by 45° “sweeps.”
- Tires are BFGoodrich G-Force R-1s on the Cup car. The Roadster is going to run the same tires on it, for consistency of performance between the two cars. The mandated tires for the NR-A car are a Bridgestone RE-11 tire, but they aren’t a DOT-R compound, so to minimize any competitive disadvantage it was decided to be consistent, even if not 100% correct in this particular case.
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