For nearly as long as there has been electronic fuel injection there has been ways to tune it. In the last 20 odd years there have been two main competitors for end users to choose from at the cheaper end of the market, the Greddy E-Manage and the Apexi Power FC.
The main difference between the two are the E-Manage is a piggyback system which keeps the original ECU for running most of the car functions and the Power FC, which is a full replacement, standalone system.
The theory behind how the E-Manage works is sound, it intercepts the signals to the fuel and ignition systems and alters them to allow the engine to be tuned. The trouble with this is the standard ECU still has some control over its closed loop functions and can cause the tune to ‘wander’ over time. With the Power FC being a complete replacement it doesn’t suffer from this.
‘So if the E-Manage wanders why do people still use it?’
Two main reasons, price and availability. People normally choose bang for buck over true value for money. They are also a lot more readily available over other ECU systems as people have removed them from their cars.
This customer is a prime example of the real benifits of choosing a real standalone ECU such as a Power FC over the E-Manage. They bought the car running 10psi of boost tuned on an E-Manage blue and felt it was holding back at the top end, as a safety measure they reduced the boost by just running actuator pressure of ~7psi. Before changing the ECU we ran the car on the dyno to get a base line power, it put out 183.7bhp/ 168.9lbft of torque at the hubs at 0.5bar of boost.
As the E-Manage was on a boomslang harness swapping in the Apexi Power FC was a 2 second job. With it installed and all the base line settings made we could begin tuning. The 1ZZ fitted in this MR2 has variable valve timing (VVT) and in stock form puts out 140bhp/125.8lbft of torque at the flywheel from the factory.
With this engine being turbocharged after market and already putting out over 50bhp and 50lbft more than stock, you would think the original set-up was good. One thing that the Power FC has over the E-Manage is total control over the VVT, this gives us the chance to get even more power out of the engine with very little effort. In fact, at 0.34bar of boost we managed to achieve 226.6bhp/ 233.1lbft of torque at the hubs before running out of fuel delivery and having to call a stop to the session. This a gain of 42.9bhp/ 64.1lbft over the previous tune, well over 100 bhp over stock figures for the engine and right at the limit of the transmission components.
As you can see from the graphs there is a huge gain over the entire power band and the owner has already reported back that the car is transformed. At its last sprint event the car lead the class by over 2 seconds, it’ll be interesting to see how it goes over the weekend.
Read why we managed to get more power from less boost in our next blog post.