The two different firing orders questions

[eschaider]

Originally Posted by Dumpling

I actually read things before spewing non-sequitur replies...

I think you are becoming defensive without reason. You are not being attacked. While you obviously have an ECU, that while dating back to first generation technologies, is from all appearances none the less serving you quite well. That is excellent.

Your knowledge of Ford ECUs, ECU strategies, what they support and what they allow appears somewhat limited but that does not necessarily impact the utility you realize from your ECU choice. It does however misinform those that might be reading these posts hoping to pick up knowledge to help them in their own efforts.

Because the 03/04 Cobra’s used an Eaton with a 1.9L swept volume pulleyed to supply 8psi of boost, Ford built the 03/04 EEC-V Cobra processor with a hard stop in their MAF transfer function at 64 pounds of air per minute. In round numbers it takes 10 pounds of air per minute to produce 100 HP. A MAF transfer function that can provide a 64 lb/min upper limit would handle a 640 FWHP engine. The general opinion in Ford Engineering, at the time, was that this was a robust and generous allocation.

Once the cars got into the hands of enthusiasts and larger blowers from KB and Whipple began to appear on the engines, the engines quickly eclipsed what Ford originally believed to be a very generous hard stop in their mass air flow measurement code. An early aftermarket fix was the use of a switchable resistor pack between the MAF and the CPU to modify the voltage the ECU saw so that it could be ‘fit’ into the preordained space Ford Engineering provided.

That worked, with some loss in resolution, as long as the overage was relatively small. Because substantially more air, was available with the aftermarket screw blowers, the MAF transfer function ultimately needed to be scaled to stay within the hard coded limits Ford engineering provided.rather than modifying the MAF voltage output with a switchable resistor pack.

When Ford built the Cobra version of the EEC-V ECU they built upon the success they had realized with their previous generation EEC-IV ECU’s. By setting the MAF Transfer function ceiling at 64 pounds of air per minute they believed they were safely above any air demands their customer’s engines might see. In retrospect we now know they were not. The air flow limits on the EEC-IV ECU’s like you are using were lower compared to the EEC-V supercharged Cobra limits — which, as it turned out, were themselves restrictive.

The EEC-IV processor and piggyback EPEC you are running will use either an A9L or an A9P ECU in the EEC-IV. The last strategy Ford released for the A9L ECU’s was the GUF-B strategy which was used in 5 speed versions of the car. If the car came with an automatic, the ECU was labeled an A9P and was delivered with a GUF-1 strategy supporting the automatic version of the vehicle. Performance fans typically opted for the GUF-B strategy unless they used an auto, in which case they would use the GUF-1 strategy.

Irrespective of strategy used, the maximum air flow OEM software can recognize is below the 64 pounds per minute that the supercharged 03/04 Cobra strategies supported. The fix for this is to scale the MAF xfer function and also a number of additional parameters, including injector flow stats. If you do not do this then you will have an unpleasantly tuned engine. Additionally if you repeatedly bang into the MAF transfer curve’s ceiling flow rate, because you did not scale the MAF xfer function, then you will lean out the engine and eventually do damage to it even though it is not supercharged.

Your implementation apparently does not do this which means the ECU + EPEC package at least accommodates your power level fairly well. The Ford supplied EPEC MAF transfer software package most likely scales the original MAF transfer function and the associated functions it interacts with. Just like on the later EEC-V ECU's when you scale this metric you experience a reduced resolution in the MAF transfer function, and potential load aberrations depending on the amount of scaling required. The load aberrations directly impact the fidelity of the fueling model at any given point in the engine's operating range.

For guys who are only now electing to transition to EFI they would be much better served with an aftermarket package than any of the packages Ford has offered over the years. They are faster, have more tuning features, more capabilities, do not require scaling internal fueling metrics and definitely provide more engine save routines.

And by the way this whole discussion is off topic for this thread.