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Lotus Eleven/Elise/Exige. Manual - part 129

Lotus Service Notes

2-Eleven

Page 10

Compression (bump) damping is adjust-

ed by turning the knob on the end of the gas

reservoir canister: Turn clockwise to increase

damping, and couterclockwise to decrease.

Recommended settings are as follows:

Road use: 15 clicks from full hard

Track use: 10 clicks from full hard

Rebound damping is adjusted via a

ribbed collar below the bottom spring seat:

Turn clockwise (as viewed from below) to

increase damping, and counterclockwise to

decrease. Recommended settings are as

follows:

Road use: 15 clicks from full hard

Track use: 12 clicks from full hard

All cars are equipped with through bolted spherical joints on the inboard ends of the rear toe-links, allied

to a tubular steel crossbrace connecting the rear sides of these joints to provide 'double shear' support. For

suspension geometry refer to Section 2-ELEVEN.TD - TECHNICAL DATA.

Rebound

adjustment

collar

d50aB

Page 11

Lotus Service Notes

2-Eleven

2-ELEVEN.E - ENGINE

The 1.8 litre 2ZZ-GE engine with VVTL-i (Variable Valve Timing and Lift - intelligent) as used in other

Elise/Exige models, is ﬁtted with a low pressure Roots type Magnuson MP62 supercharger to provide up to 0.5

bar (7 psi) of boost pressure. The supercharger is mounted on the left hand side of the block and driven by a

lengthened version of the multirib auxiliary belt. The unit is self contained and features helix twisted rotors to

minimise output pressure variations, and maintenance free gearing and bearings, requiring no externally sourced

lubrication. An integral by pass valve under ECU control, operates to recirculate air from the compressor outlet

back to the inlet under conditions of idle and part throttle to the beneﬁt of economy and quiet operation.

The supercharger is hung off the new intake manifold by two bolts in conjunction with eccentric sleeves in

order to ensure stress free alignment. An alloy bracket supports the nose of the unit to the RH engine mounting

plinth, and a tubular strut braces the intake end of the unit to the clutch slave cylinder mounting point.

Air is drawn from an enlarged air cleaner through the throttle body and adaptor and into the supercharger

axial intake port. From the outlet port on the compressor top surface, the air is directed through a stainless

steel duct to the LH end of an air/air chargecooler mounted behind the engine, where airﬂow gathered from

an intake duct in each of the body sides aft of the cockpit, is directed by convoluted ducting to a chargecooler

shroud and through the radiator ﬁnning to cool the compressed intake charge. The cooled air exiting from

the RH end of the chargecooler ﬂows via another stainless duct into a cast alloy intake plenum/manifold. The

whole intake tract uses large diameter ducting and generously radiused bends to optimise airﬂow and intake

efﬁciency and minimise any potential throttle lag. A charge air temperature sensor is mounted in the outlet

tank of the chargecooler.

Each end of the chargecooler is mounted by two alloy spacers to a fabricated steel mounting bracket se-

cured to the engine crankcase by a single ﬁxing bolt. A bonded rubber bush at this position supresses vibration

effects, and in conjunction with the rubber hose connections to the inlet and outlet ducts, provides an isolated

mounting of the chargecooler.

A re-shaped breather pipe is used to connect the crankcase breather spigot to the cam cover and circum-

navigate the supercharger.

Road going cars use the standard catalytic converter, which is substituted by a plain pipe on track cars,

but all versions are ﬁtted with a unique exhaust mufﬂer, featuring a double pass design, with single RH tailpipe

exiting through the rear transom panel.

Four special high-ﬂow port fuel injectors are used (common with Cup cars and USA Exige S) in conjuction

with unique engine programming, which incorporates control of the supercharger by-pass valve. The boost

characteristics have allowed the switching point from low to high lift cam proﬁle to be varied between 4,500

and 6,200 rpm dependent on engine load (at normal running temperature). Twin front mounted oil/air coolers

are ﬁtted one each side, ahead of the front wheels.

Accusump

To provide protection against the possibility of oil starvation caused by the extreme g-forces possible with

track use on slick tyres, the 2-Eleven is ﬁtted with an Accusump oil storage system.

A 2-litre Accusump reservoir is mounted

behind the engine on the left hand side of the

rear subframe, and is plumbed into the LH oil

cooler return hose at the front of the engine

bay. The device comprises an alloy cylinder

divided by a sliding piston, one side of which

is connected to the engine oil supply, with

the other containing pressurised air. With

the engine running, the cylinder is charged

with oil provided by the engine oil pump, but

if the pressure should drop for a short period

due to oil pump pick up pipe exposure during

extreme braking or cornering events, the ac-

cumulator air pressure forces the stored oil

into the engine lubrication system to maintain

continuity of oil supply until normal conditions

are resumed.

Pressure

gauge

Accusump

reservoir

e234

Lotus Service Notes

2-Eleven

Page 12

pl4610cca

Connection to chargecooler Chargecooler inlet duct

outlet & inlet

New inlet

manifold

Supercharger

outlet connector

Supercharger

outlet elbow

Supercharger

outlet adaptor

Mounting lug Swan neck

for supercharger adaptor

ﬁxings

Chargecooler Fixing point (s/c inlet)

outlet duct to manifold

By-pass valve

Fixed to engine capsule

mounting plinth

Front

Support strut to clutch

slave cylinder mounting

Alternator anchor

e235

Cooling air intake duct

Chargecooler

Collector

Outlet to engine

Charge air

temperature

sensor

Cooling air Alloy

trunking to Inlet spacer

chargecooler from s/c

Rear

Fixing bracket to

to crankcase

Fixing bracket to

clutch housing Spacers

Page 13

Lotus Service Notes

2-Eleven

A one-way valve at the oil cooler connection of the 'T'- piece ensures that the oil discharged from the

Accusump is directed into the oil pump and not the cooler. An Electric Pressure Control (EPC) valve ﬁtted at

the connection to the Accusump cylinder, allows cylinder charging when oil pressure is above 35 - 40 psi, and

cylinder discharging at engine oil pressures below 35 - 40 psi. The EPC is also linked to the ignition switch

such that with the ignition switched on the valve is open to allow oil ﬂow, and with ignition off the valve is closed

to retain oil within the reservoir.

Normal Operation

When the ignition is turned on, the EPC valve on the Accusump is opened, allowing the pressurised oil

stored in the reservoir to ﬂow out into the engine and prime the oil galleries and bearings ready for start up.

When the reservoir has been emptied, the pressure gauge on the end of the reservoir will indicate the pre-

charge pressure which should be 7 - 15 psi.

When the engine is started, engine oil pressure will force the reservoir piston back, such that the reservoir

air pressure gauge will indicate engine oil pressure, with the quantity of stored oil dependent on this pressure

at any one time. With cold oil, 80 psi may be seen, but idling at normal running temperature should produce

around 30 - 40 psi. Note that the pressure reading on the reservoir gauge is damped and will lag behind the

actual instantaneous pressure. A pressure relief valve in the end of the reservoir protects the equipment from

over-pressure damage. If oil is seen to escape from this valve, a fault in the lubrication system is indicated, or

excessive rpm have been used with cold oil.

When the engine is stopped, the EPC valve closes and a quantity of oil pertaining to the oil pressure at

that time, will be retained in the Accusump ready for re-starting.

Routine Checks

Be aware that the indicated oil level on the dipstick will depend on the amount of oil stored in the Accu-

sump, which itself is dependent on the both the Accusump pre-charge air pressure and the engine oil pressure

when the ignition was switched off.

Before checking the oil level, the Accusump pre-charge pressure should ﬁrst be checked; turn on the

ignition to open the EPC valve and allow the stored oil to be discharged from the Accusump. The pressure

gauge reading will drop during this discharge, but should then register 7 - 15 psi representing the pre-charge.

If necessary, adjust the air pressure using tyre inﬂator equipment on the Schraeder valve adjacent to the gauge

and set to 15 psi. Allow adequate time for the gauge reading to stabilise.

The oil level should now be above the top

mark on the dipstick. To check for correct oil

level, the engine should be started to charge

the Accusump, and run to normal operating

temperature until the Accusump pressure

gauge registers 40 psi. If the engine is already

hot, idle oil pressure may not be sufﬁcient to

open the Accusump valve, and the pressure

gauge will continue to show 15 psi pre-charge.

Increase engine rpm to open the valve. With

the gauge showing 40 psi, turn off the engine.

The EPC valve will then close and trap the

normal hot idle quantity of oil in the Accusump

cylinder.

After a suitable oil drainback pause, the sump oil level may then be inspected on the disptick, and the

level corrected to the top mark. It is important to maintain oil at this level to accommodate the oil transfer into

the Accusump at pressures greater than 40 psi. Be aware that checking the oil level under any conditions other

than 15 psi pre-charge and 40 psi oil pressure will produce inconsistent results.

Oil Changing

Before draining the sump, the ignition should ﬁrst be switched on to open the EPC valve and allow the

Accusump to discharge the stored oil into the sump. Check that a pressure of 7 - 15 psi remains in the Ac-

cusump at the end of this process, and if necessary top up the pressure using tyre inﬂating equipment on the

Schraeder valve next to the gauge and set to 15 psi.

ohs149aB

OIL FILLER CAP

ohs131aB

DIPSTICK

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