Lotus Evora, Service Notes

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Lotus Service Notes Section DJ
DJ.1 - GENERAL DESCRIPTION
The independent rear suspension comprises, on each side of the car, upper and lower forged aluminium
wishbones, a forged steel toe control link, a concentric coil spring/telescopic damper unit, and a tubular steel
anti-roll bar, all being attached to the galvanised steel rear subframe. A forged steel hub carrier, provides a
mounting for the hub bearing unit to which the 5-bolt road wheel and brake disc are attached, and also carries
bosses for the cross-axis fixing bolts for the brake calliper.
The primary, vehicle weight bearing, lower wishbone, is widely based and substantially cross braced, and
incorporates separate double shear mounting points for the hub carrier and damper lower eye, and a single lug
for the anti-roll bar drop link. The outboard end of the wishbone is through bolted to a spherical joint pressed
into the lower eye of the hub carrier. The upper wishbone is of simple 'A' form, and houses a replaceable
through-bolted spherical joint at its outboard end to connect to the hub carrier. The inboard ends of both upper
and lower wishbones use replaceable bonded rubber pivot bushes for maintenance free articulation, with the
bush compliance profile tuned to provide the vehicle with accurate and responsive dynamic characteristics. The
toe control link is a two part steel forging incorporating an adjustment turnbuckle, and by connecting a rearward
extension on the hub carrier to the chassis subframe, a 'toe-in on compression' bump steer characteristic is
produced. Through bolted spherical joints are used in each end of the link, and the threaded turnbuckle allows
for adjustment of rear wheel alignment. An eccentric cam incorporated at the rear pivot point for the lower
wishbone, provides a means of camber adjustment.
The bottom of the Bilstein monotube telescopic damper fixes to the lower wishbone in a double shear
arrangement, with the damper top end secured to the subframe via a steel bracket bolted inside the subframe
tower. The damper uses a rubber bush in the top eye for noise suppression, and a through bolted spherical
steel joint in the lower eye for optimum dynamic response, and is orientated with the damper rod uppermost.
The dual rate, concentric coil spring abuts against a lower seat fixed to the damper body, and an upper seat
secured to the damper top eye, but also bolted to the subframe, thus relieving the damper top bush of vehicle
weight to the benefit of noise and ride refinement. The close coiled end of the spring is mounted lowermost,
on the damper body.
A 21mm o.d. tubular steel anti-roll bar is mounted in rubber bushes to the underside of the subframe
rearward of the axle line, and curves over each toe-link before connecting to the lower wishbone rear leg via
a short ball jointed drop link.
The hub bearing unit, which is common to all four wheels, is fixed to the hub carrier by 4 bolts, and in-
corporates a wide spaced double row ball bearing and a vehicle speed sensor ring integrated into the inboard
seal, whose 48 pole signal is picked up by a sensor mounted in the rear of the hub carrier. This data is used
for the anti-lock brake, vehicle stability, engine management and speedometer functions.
DJ.2 - GEOMETRY & ADJUSTMENTS
Provision is made for the adjustment of wheel alignment and camber. Under normal service conditions, no
periodic scheduled check of the geometry is necessary, with a full geometry check required only after suspension
repair, or if excessive tyre wear is evident, or handling deficiencies encountered. Before any measurements or
adjustments are made, it is essential first to set the vehicle to its ‘mid-laden’ ride height, approximating to driver
and passenger and a half/full tank of fuel. This will require the vehicle to be ballasted or tied down:
Type Independent. Upper and lower wishbone; co-
axial coil spring/telescopic damper; toe-link;
anti-roll bar
Mid-laden ride height (2 x 75 kg occ full fuel tank) - set car to this height before measuring geom-
etry: - front 125 mm below front end of chassis siderail
- rear 147 mm below rear end of chassis siderail
Camber - optimum - 1.6°
- tolerance range - 1.8° to - 1.5° max. side/side 0.2°
Alignment - optimum 1.5 mm toe-in each side
- tolerance range 1.4 to 1.8 mm toe-in each side
max. side/side 0.3 mm
Thrust angle - optimum Zero
- tolerance 0.05°