V8 ECU's
Specs straight from the Factory

There has been talk among V8 owners about the factory spec ECU's for the V8. Rumours of different codes for US and European models. Extra power for Sport 350's and a Race version. Lotus Esprit World would like to clear up the specs for the ECU on this page, telling you exactly what's available and what the differences are.

Remember this information is for the factory calibrated ECU's and not any aftermarket ECU's or Chips. The figures are also produced on standard V8 Esprits without any modifications of any parts.

Lotus supplied V8 ECUs

1. Standard Production ECU
2. Sport 350 ECU
3. Race (Red) ECU (mainly USA)

All 3 sets of Data are loaded to the ECUs at Lotus and distributed to Lotus Aftersales network for Worldwide distribution.

Standard ECU has a calibration that produces 350 BHP and 400Nm (400Nm is only available in 5th gear, other gears have progressively less to suit Gearbox limit. This is done by reducing boost throughout the rpm range in each gear to reduce torque to match the gearbox limits.

Sport 350 ECU has a calibration that also produces 350 BHP and 400Nm. 400Nm is available in all gears except 1st. This is possible following some gearbox improvements/updates. This has the same boost reduction in 1st gear as the Standard coding, with all other gears producing up to 400Nm of torque.

Race (Red) ECU has calibration that also produces 350 BHP and 400Nm. This coding has no reduction of boost through its rev range and can produce maximum torque in all gears. This has been sold mainly in USA for 'Track Use' and invalidates the Warranty. Apart from the first gear the calibration for Sport 350 and Race are identical.

We do not recommend the Race calibration (high torque in first gear) for road use as it overloads the driveshafts. Most of the extra torque will be lost in wheelspin so there is not much advantage to be had.

The boost levels and Power Figures certified by Lotus are steady state Dyno. figures.(production inlet & exhaust systems) corrected to the relevant standard. What some people may be stating for boost are transient figures which can be seen for extremely short periods during full throttle accelerations through the gears. These figures can vary depending on the inlet & exhaust system fitted to the car. Lotus have a target Transient Boost curve that is expected but can vary depending on vehicle conditions.

There has been claims of huge bhp from the Race (Red) ECU's, but if Lotus were running engines at 440+ BHP they would be having piston failures (similar to the ones shown at the Oxford Meeting), as the pistons aren't strong enough to run at higher HP. Lotus have been seeing quite a few failures at the factory. Also the vehicle cooling system (water & oil) is not designed or capable of dealing with much more than 350 BHP. So any claims of high horse power from factory calibrations aren't accurate.

Below is Lotus Boost Curves for the Standard ECU & Sport 350 ECU. Remember every car will have some variable due to production tolerances of many components. What is important is that the differences in the calibrations can be seen. Also included are the rough figures for the transient boost on each graph.

What is known as 'High Torque' in USA is same as used on the European Sport350. The later USA cars (2002/2003) had this calibration as an update for the final batch of cars built.

This specification was planned for the USA market only. However a few Euro specification vehicles were produced to special order.
Several different part numbers exist for ECUs that appear to be similar as far as the customer is concerned. Updates for USA diagnostics necessitated modifications that had to be incorporated in MY updates. The ECU data for the Engine Performance is not necessarily affected by the MY update even if the Part Number has changed.

In the early V8 days lotus had different ECU variants for USA & Euro certification. This depended on whether the vehicle / engine specification demanded extra emission requirements such as EGR and Air Pump.

Later USA cars demanded more complex diagnostics to monitor features such as Fuel Tank integrity which checks the fuel tanks for leaks. Euro cars (Engine Build Spec. and ECU specification) were commonised towards the end of production.

Post 1999 V8 ECU's
The Sport 350 calibration was basically only for the Sport 350. It was considered during the 2002 MY update to release the Sport 350 Calibration for all cars. This did not happen as it was thought that it would be unfair to the current Sport 350 owners (who have a very special car) to let the 'Standard' car have the enhanced performance.

However a few lucky owners of the last produced cars had an unexpected bonus!

The gearbox improvements introduced at that time of the Sport 350 did go on all subsequent UN1- 027 Gearboxes. Lotus normally carry over improvements to all cars but in the case of ECU calibration this does not always happen.

Remember, any increase in performance will give a decrease in reliability and an increase in wear.