Rear Mods to FC16308L Mk1 Spitfire
Assembled uprights.JPG (20216 bytes) Assembled Uprights with Swaybar Brackets.JPG (32270 bytes)
Outer Stub Axle.JPG (59826 bytes) Modified Upright.JPG (63611 bytes)
Vette Diff-Front.JPG (43206 bytes) Vette Diff-rear.JPG (36439 bytes)
 

Diff Right oblique.JPG (55169 bytes)

Right rear view.JPG (42836 bytes)
Boot mod.JPG (49431 bytes) Interior diff access.JPG (42372 bytes)
Right side view.JPG (74805 bytes)
These photos show the installation of a  Dana 36  Aluminum differential from a late 90's Corvette.  The rear cover contains the mounting bracket which had to be shortened several inches to mate with the uprights of the Spitfire frame.  The gears are 3.54:1 which is a pretty good match with the Honda S2000 engine and 6-speed gearbox set on 13" wheels and 20 inch tall tires. 

To mount the differential, the rear of the frame was removed and reinforced using 1 inch square thick wall tubing.  Koni 8212-1416 double adjustable shocks using B3 valving.  The springs are 9" long x 2.25" diameter Hypercoils with a rate of 300 pounds.  The interior of the car had to be modified to add space for the larger diff.  An access panel was installed for easy access to the top of the diff and handbrake cable routing.

The addition of an upper control arm was necessary to support the coil-over shocks and eliminate the transverse rear spring.

The axle shafts were constructed using Spicer slipyokes normally used as output yokes on automatic transmissions.  Custom shafts were constructed by Moser Engineering to slide into the slipyokes and into Porsche 930 CV-Joints on the outboard side.

The GT6 rotoflex uprights were modified to separate the bearings by an additional inch and use the same bearing on the inner side as the outer.  The two bearings are separated by a solid spacer which sets the preload no matter how much torque is applied to the securing nut.  The shaft itself was custom manufactured as one piece that installs from the outside and is secured using a VW Bus axle nut on the inside.  Further inboard, the shaft is splined to accommodate the CV cup which attaches to the Porsche 930 CV-Joint.

The lower control arms are adjustable aluminum with Hiem joints on the ends.   These are provided by Clive Averill but were modified for this application by shortening the rear one about 1/2 inch.

Since the inside of the wheel wells were modified to clear the additional hardware, aluminum covers were fabricated to cover it inside the boot.

With the addition of the much stiffer rear suspension, a 1" front swaybar was added in place of the 5/8" one previously used.