Shogun, from stock to +700BHP extreme

7 minute(s) of a 74 minute read

This is how I rebuilt a Z32 gearbox to fit my car (200sx S13 with ca18det).

The good thing about it is that you can reuse the nice clutch you already invested in for your S13. I have a twin disc OS Giken clutch, bought for my S13 gearbox. Both gearboxes have the same dimensions on the ingoing splined shaft, release bearing, sleave etc. This makes it an absolute fit. The gear ratio is slightly higher. My car had before a top speed of 282km/h at 7800rpm. With the ratio of the Z32 gearbox and new tyres it will make aprox. 305km/h. Hope you like it.

Clutch: Same as S13 (clutch, bearing, release sleave, starter motor, flywheel)
Weight: A bit heavier because of internal dimensions
Length: A bit shorter (reuse the yoke from the Z32 and the rear part from theS13 and make a new, longer prop shaft)
Gear ratio: A bit higher (~5%)
Shift stick: Reuse the one from Z32 or buy a new short shift
Welding in cast aluminium: You need a TIG or go to a welding shop (sand blast the weld area to make it clean and easier to weld)

Z32 original gearbox from a Twin Turbo 1994






Disassemble the clutch housing (Z32)

Parts to remove to disassemble the clutch housing. Not shown are the screws on the outside (remove), attaching the cluth housing to the gearbox.

Remove all screws around the cover and carefully lift it off

Remove both snap rings and the stopper ring

Be careful not to lose any important washers or shims

Important! First remove the screw, spring and ball before removing the complete interlock assembly, the ball might fall into the gearbox.

Before you disassemble the clutch housing of the S13 gearbox, you have to make a centering device. Use a plexi glass plate (10mm) and drill a 16mm hole in the centre, put the plate over the shaft (snug fit) and carefully drill 4 small holes exactly in the centre of the holes where the gearbox is attached to the motor. Remove the plate and carefully drill the holes just as big to get the screws in

Result

Remove the clutch housing from the ca18det S13 gearbox. It is more or less just to remove the screws on the outside of the clutch housing, remove the cover and one snap ring.

Remove the snap ring under the cover

Comparision between the both gearboxes. One is useless over 350-400Bhp, the other last well over 1000Bhp and more.

Use an angle cutting machine and cut off the flange from the S13 gearbox ca. 50mm, take it to a machine shop and have it grinded down to 45mm. Important to get it absolutely flat and equal all around.

Use an angle cutting machine and cut off the flange from the Z32 gearbox ca. 40mm, throw away the flange and take the rest of the clutch housing to a machine shop and have it grinded down to 355mm. Important to get it absolutely flat and equal all around.

Both parts after grinding, cleaning and reattaching the clutch housing on the Z32 gearbox

Put the S13 flange snug to the Z32 clutch housing and attach the centering plate with four screws

Side view

Top view. Important to align and rotate them like on the picture

If you do not own a TIG-welding machine, you go to the machine shop again and have it carefully welded together, both from the outside and the inside

Reuse the shift stick bracket from the Z32 gearbox. You have to cut out some small triangles from it, bend it to a Z-shape to fit the S13 under body and then weld the cut outs together. (borrowed picture)

The new short shift

A small change of shift stick position compared to the original (borrowed picture)

A plate to cover the hole at the shift stick (borrowed picture)

A bracket to hold the gearbox in place (borrowed picture)

Aligning the gearbox with the rear axle. Put a steel tube in the gearbox, aim it towards the centre of the rear axle flange and find the final position of the gearbox bracket. (borrowed picture)

Side view (borrowed picture)

Front view (borrowed picture)

The prop shaft. Mount the Z32 yoke in the gearbox and the original flange on the rear axle. Measure the centre distance between the loops in the yoke and in the rear flange. Use this measure and go to your local prop shaft supplier and have him to make your new prop shaft. The shaft rotate at about 10.000rpm at max speed so it has to be dimensioned for the forces and also balanced.