Lotus Type 918 3.5 litre, Twin turbo, Quad cam, 32 valve V8
90 degree cylinder bank angle, single-plane crankshaft.
Bore: 83 mm
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!