Metrics
Weight
Performance
K20 Swap
Disassembly
Cooling
HVAC
Firewall
Fuel System
Electrical
Engine
Mounts
Exhaust
Misc
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Why?
Why swap the Toyota 2ZZ engine for the Honda K20 engine? Simple - the Honda engine is better in every regard than the Toyota engine - more powerful, larger capacity, cheaper, more compact, lighter, stronger, easier to tune, better supported in the aftermarket. When designing the S2 Elise, Lotus did approach Honda for the K20, but was turned down for some reason.
The history of the 2ZZ engine is that it was commissioned by Toyota to compete with the Honda B18C Spec R engine. On paper the 2ZZ performed well - although it's 185 hp was 15 hp less than the B18C and only as good as the smaller Honda B16B. By increasing the size of both the intake and exhaust valve by 1mm over the B18C, the 2ZZ cylinder head out-flowed the B18C, however smaller bore centers were used (87.5mm vs 90mm) and a cam-over bucket style camshaft was used which ultimately limited power. Furthermore, the torque curve of the 2ZZ is very poor - suffering a large torque hole between 3500 and 6500 rpm. The 2ZZ was introduced in 2000, and within two years Honda discontinued the B18C and replaced it with the K20A The K20A uses a bigger bore center (94mm), bigger valves (both another 1mm bigger than the 2ZZ), a better flowing cylinder head, roller followers on all three cam lobes, 50 degree variable intake cam angle; all making the engine produce another 20 hp over the B18C and 35 hp over the 2ZZ, yet the engine / transmission package was significantly more compact than either the B18C or 2ZZ. All these characteristics make the K20A an ideal choice to power the Lotus.
Honda Engine Swap - Progress - 12 May 2008
Front end mostly compete. No engine mounts.
Honda Engine Swap - Progress - Oct 2008
Engine ready to run for the first time.
Honda Engine Swap - Progress - Oct 2008
Complete.