Lotus Type 918 3.5 litre,
Twin turbo, Quad cam, 32 valve V8
90 degree cylinder bank angle, single-plane
crankshaft.
Bore: 83 mm
Stroke: 81mm
Capacity: 3506 cc
Head Chamber Aluminum alloy, four-valve pent-roof
Valvegear: Dual overhead camshafts with one toothed belt per bank, hydraulic
tappets.
Inlet valves: 33.5 mm
Exhaust valves: 30.0 mm
Block: LM25TF aluminum alloy , cast iron "wet" lines, spheroidal graphite
cast iron cross-bolted main bearing caps.
Turbochargers: Two Garrett T25 water-cooled, oil lubricated (To be
upgraded)
Fueling: One primary injector per cylinder, one secondary injector per
bank.
Ignition: Four double-ended coils triggered from crankshaft sensor.
Ancillaries: Water pump, alternator, power steering pump, air conditioning
compressor.
Weight: 485 lb with ancillaries.
It's worth noting above that "single-plane" , or "flat plane" crankshaft configuration is used in the type 918 V8 (as opposed to the "cross plane" crankshaft used by less exotic V8s (as typified by American versions) - click here for an explanation
Pistons are very important in high boost applications (if you want them to
last!) - I'm replacing the standard Lotus V8 pistons with forged Mahle pistons.
Wahl pistons are about as good as you can get and will be ideal for this
job - I'm also had them Keronite coated, which is a process that's being
used quite extensively in WRC apparently with very good results ...... the
coating is extremely hard and has a very high degree of thermal insulation,
This should allow for some serious boost!
This picture shows the route of the hig pressure inlet from the turbos into
the V8 plenum - the plumbing will need adapting here, to fit the twin
chargecoolers **Update** I'm now using the GT1 racing plenum - see Progress
section
So, as mentioned in "The Plan" section, I'm using twin Lotus chargecoolers
to allow higher boost pressures. A lot of the thought here is taken from
the Le Mans Esprit V8 racing cars (GT2) and the similarly engined Elise GT1
racer. The works V8's used 1 bar of boost when they used a single large turbo
and 1.2 bar of boost with twin turbos. Now, they had to run with 33mm air
restrictors but with mildly fettled heads, the end result was 540hp!
**Update** I'm now using the Lotus Carlton twin chargecooler unit - see Progress
section
Dutch car chargecoolers
Garrett car chargecooler
The photo above is of the original GT2 Esprit race car. You may not have
browsed the "Progress" section and seen photos of my engine complete with
the plenum and chargecooler... this sneak preview shot maked for a great
comparison though... I think it's getting about right!
