Ignition: twin Bosch magnetos; gear driven from rear end of crankshaft.
Lubrication: dry sump lubrication.
Transmission: was an all-indirect gearbox at rear. 5 speed on A
type, 4 speed on B and C types; (as a result of 1st gear being
blanked of due to the immense torque of the V16. ZF limited slip differential
on C type. Multiplate clutch on all types.
Chassis: Welded tubular frame of chrome-molybdenum steel.
Twin training links with bottom arms linked to transverse torsion bars,
top arms linked to friction type shock absorbers.
Rear suspension: 1934 A type: transverse leaf spring with swing
axle and longitudinal torque arms. 1935, B and C types: transverse leaf
spring replaced by longitudinal torsion bars, friction shock absorbers.
D type: Porsche type twin trailing arms with torsion bar springing and
double action shock absorbers. Rear, De Dion type with Panhard rod, torsion
bar springing and double action shock absorbers.
Fuel: capacity 46 gallon fuel tank mounted on frame between drivers'
compartment and engine
Cooling: film radiator mounted on the front cross member of the
frame. 100% ethylene glycol coolant running through separate coolant tubes.
The normal operating temperature was between 85-90 °C. (in the A type
the coolant ran through the chassis tubes but this was abandoned when
the fluid leaked as fractures in the welds occurred as the chassis flexed.
Steering: worm and rocker shaft to individual track rods 16 1/2
in. dia. steering wheel. About 2.1 turns lock to lock.
Brakes: were initially Porsche designed expanding band type brakes
but performance was erratic so these were replaced by two shoe hydraulically
operated brakes with rigid light alloy shoes. Finally, on the type D car,
to combat brake fade these were replaced by four shoe brakes with a hydraulically
operated cylinder per shoe. The shoes were of fabricated steel, which
allowed a degree of flexibility.
Wheelbase: A type 9 ft. 4 in B type 9 ft. 5 1/2 in C type 9 ft.
6 1/2 in D type 8' 8"
Wheels and Tyres: Continental 5.25 x 17 front 6 1/2 or 7
by 19 or 22 (race dependant)
Weight: A type 16.6 cwt; B, C type 16.2 cwt; D type 23.4cwt
Maximum speed: 172-195 mph.