The OS Giken OS-88 gearbox is a sequential 6-speed gearbox designed to suit the BNR32 and BCNR33 GT-R.
It can also be used in the BNR34 but will require an R33 transfer case and front prop shaft.
It bolts up to the Nissan transfer case and has a bellhousing to suit any RB engine.
It also comes complete with shifter, digital shift indicator and pull-up reverse lock-out sleeve.
OS Giken designed this sequential gearbox to handle 1500hp, while retaining quiet helical-cut gears.
To do this the gear axis has been increased to 88mm, while most internal parts are forged. The dog-engagement of the gears allows extremely fast shifting operation.
The gearbox uses a 26-spline GM input shaft size (same as Holinger) so it needs a clutch with this spline. OS Giken has R3C triple and R4C quad-plate clutches available to suit.
This version of the gearbox ('option 2 ratios') is suited for street and drag racing use. The first ratio is taller than standard but not as tall as other OS88s. The 6th gear is also taller than in other OS88s as it would not get used anyway on the dragstrip.
1st – 2.890 / 2nd – 1.981 / 3rd – 1.468 / 4th – 1.174 / 5th – 1.00 / 6th – 0.757