Below are expanded descriptions of features that are included with the S4 TII Stage 1 Rtek7 ECU Upgrade.
The stock ECU will cut fuel to the rear rotor when boost hits the fuel cut threshold of about 8.6 psi. Although this was put into the stock ECU as a protection mechanism, it's a quite harsh mechanism and not required for mild improvements in boost.
Up until now, a Fuel Cut Defensers (FCDs) have been external devices wired into the engine harness that interrupt the signal from the boost sensor to the ECU. The Rtek7 goes goes right to the source by removing the code responsible for Fuel Cut from the ECU altogether. This has the additional benefits in that it doesn't alter the boost signal to the in-dash gauge, there are no wires to splice, and no additional box to clutter the engine bay.
CAUTION: Running too much boost without enough fuel can destroy an engine. Even though the FCD is built into the ECU, it is the customer's responsibility to address fuel requirements separately.
Secondary Transition Stumble Elimination:
Under certain conditions, the stock ECU can cause an engine stumble right at the secondary transition point (around 3500-3800 RPM) when the manifold pressure is at zero PSI. We have changed the code in the ECU to eliminate this problem.
When you first start your RX7, the ECU will rev the engine to approximately 3000 RPM's - this is the Accelerated Warmup System (AWS) in action. The purpose of the AWS is to warm up the precat. Of course, one of the worst things you can do to a cold engine is high revs. This mod removes the AWS code from the ECU allowing your car to idle normally when cold.
The Rtek7 Upgrade eliminates the need to pop the hood to pull a fuse when the engine is flooded. Simply press the accellerator to the floor and crank. The ECU will now stop fuel delivery for as long as you keep your foot on the floor.
Minimum Injector Size:
This is the size of the injectors that the ECU is expecting.
The injectors MUST be the same size or larger than the minimum injector size for the chip version you have or engine damage will result.
550cc secondaries are stock so no change has been made to the fuel map in version 1.5. For version 1.7, the fuel map has been corrected to compensate for larger 720cc secondary injectors without the need for external fuel control, like an AFC, to keep from running very rich. If you have an AFC, it will no longer have to trick the ECU to compensate for the larger injectors. The AFC can be used for fine tuning. This also means that you CANNOT run version 1.7 in a car with 550cc secondaries or you will run lean. Likewise, version 1.8 is expecting at least 720cc injectors for both the primary and secondaries. Injectors with any less flow will run lean and can lead to engine damage. It is OK to run larger that the minimum injector size, but be aware that you will need some sort of fuel control to keep them from running very rich, or move to an Rtek7 Stage 2 ECU upgrade.
Lower secondary staging rpm:
Normally the secondary injectors start adding fuel at 3800 RPM. The problem is that the secondary injectors will not come on below this rpm regardless of the boost being run. This can lead to cars running lean below 3800rpm even if they have larger injectors, fuel pump etc. Lowering the RPM at which the secondary injectors come on allows them to add fuel before the primary injectors start to max out.
Increase primary injector duty cycle cap by ~5%:
Raising the cap allows a little bit more out of the primary injectors. This works in conjunction with the lower Secondary Injection RPM to smooth out air/fuel ratio and get rid of the lean spot.
Timing retard above 9psi:
The stock ECU has no additional timing control for above around 9-10psi. This mod extends the timing control to give a little more safety for those running 9+ psi. Timing is pulled about one degree per PSI.