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Engine

The S2 uses the same K-series 1.8 engine as found in the original S1 standard car but features a new Lotus developed K4 engine control unit, providing improved throttle response and slightly higher engine output. It delivers 120bhp (122PS) at 5600rpm and 168Nm of torque at 4500rpm. The Elise S2 also features a three-way catalytic converter.

The S2 has an Euro III emmissions compliant On-Board Diagnostic (ODB) system which will drastically effect the number and type of engine upgrades available for the car. The new Stack instrunment pod features a Malfunction Indicator Light (MIL) which illuminates on detection of a malfunctioning engine component. This will remain illuminated until a diagnotic tool is used to reset it. In some situations unusual operating conditions can cause the light to illuminate for a short period of time.

Upgrade Routes

There are a huge number of companies offering upgrades for the K-series engines, including normally aspirated, turbo-charged and super-charged upgrade packages. Before you embark on an upgrade programme there are a number of 'must read' sites to visit:

Dave Andrews excellent page on tuning the K-series engine.
Simon Scuffham's notes on the subject.

The trick to making cost effective changes to the performance of the K-series engine is to identifiy your end-goal and to plan a direct route to it, in incremental steps that suit your budget. Only make the steps that get you there, and don't make short-term, throw-away purchases. Always buy components that have a tried and tested history and have substaniated claims that are backed up with real test data. There are plenty of people claiming huge power hikes for their products without backing up their claims with hard evidence in the form of test data. A good example of this is with performance air-filters. Why buy a panel filter, then a K&N 57i only to throw them away for an proper air-box and filter at a later date. It may cost more initially, but it makes more economic sense in the long run.


	3rd Party Upgrades Some 3rd party upgrades will trigger the MIL. Only Lotus can legally re-program the ECU to avoid this happening. ECU replacement is not legal. If a 3rd party upgrade does not trigger the MIL this does not necessarily mean that it will pass an emissions test in the future.

Upgrade Options

Due to the restrictive nature of the K4 ECU, major engine upgrade packages have been slow to appear for the Elise S2.

Lotus Cars

Lotus announced a Sport 135 upgrade package on 3rd Jan 2002. Initially it included a new airbox but subsequent testing has shown a modified, standard airbox to be as efficient and considerably cheaper. It does not include the sports exhaust. This is the factory approved option but is expensive compared to the competition. More details.

Brandes & Dschüdow

This upgrade was reviewed in a German Car magazine (Auto Bild Test & Tuning July 2002). Brandes & Dschüdow

(a German Lotus dealership has produced a 380bhp Elise S2. Together with Tekno engineering they have put an Audi V6-Biturbo engine (buld at Cosworth) in an Elise chassis extending the top speed to 315 km/h (190+mph) and lowering the 0-62mph to under 4 sec. Going along with this is a modification of the body panels making the car wider and a change of the name to Esthi < 2.7. The car also features an six speed gearbox (Audi A8), ABS, 17" front wheels, 18" rear wheels. Weight is up to 1.000 Kg and the car will be on sale in summer next year for approx. €95,000 (around Ł#163;65,000 pounds).

Power Train Projects

Power Train Projects The PTP 140 Cylinder head kit for the Lotus Elise S2 delivers increased power and torque with improved driveability and throttle response. It maintains the standard engine management system and control strategies to maintain all service and diagnostic functionality. The kit has been designed in such a way that all the parts required for installation to the vehicle along with fitting instructions are all inclusive. This is a ported cyclinger head (similar to the Elise S135 head), new ITG Maxogen airbox and filter and Janspeed sports exhaust. The package is very similar to the original S1 Sport 135 upgrade and improves torque and power curve. The parts can be bought individually (ported head Ł1250 + VAT, ITG airbox and filter Ł299 + VAT, Janspeed exhaust Ł276.60 + VAT). Buying the complete kit reduces the price to Ł1550 + VAT. It doesn't require the old head to be returned.

Thielert

Thielert sell a 150bhp conversion which does not alter the ECU and does not trigger the MIL. They are well known in mainland Europe for their upgrade packages.

Turbo Technics

Turbo Technics sell a number of superchargered conversions from 190bhp to 270bhp. I've test driven an Elise S1 TT190 and was very impressed. More information can be found on the Yahoo TT e-group

. Whilst the price of this upgrade may initially seem high, it is because you are making a single one-off purchase and not several incremental changes to reach very high power levels.