To the question of increasing the fire rate of the "extra" injector.
When installing the F/IC to fire all of the injectors, it is wired so that the PCM "fires" the F/IC. The injectors are completely divorced from the PCM and controlled, in toto, by the F/IC. Even if the control value is zero. I program in percent as it is, to me, easier to do the Math when calculating the changes to be made to the injector pulse width.
When using the "extra" injector installation, the signal to the selected injector (typically the number 1 injector) is paralleled to the F/IC and the F/IC then fires the ectra injector along with the factory injector allowing, of course, for the propagation delay in the electronics. The money involved to purchase a microcontroller and the rest of the hardware required to "multipulse" the F/IC would be, IMO, greater than the costs of a new set of 6 injectors.
Personally, I hope this works out as it will drive the cost of installation down. CobraMarty is fully instrumenting this installation and all I can see coming out of it is good things.
What would be nice is if the integrity of this Sprintex installation thread is maintained and not sniped into oblivion.
Timing. I am at over 6k' of altitude and do not pull any spark back for the first 2 pounds of boost. As far as the engine is concerned, that level of positive pressure just moved the engine down to seal level. At what is effectively 1 pound of "real" boost, I am pulling out much less than 1 degree. AND, I run on middle grade 87 Octane fuel.
AFR. I run in the mid 14s everywhere with the exception of under acceleration where the Heep drops into the mid to low 13s. I do have one special condition where it will hit 12.9 and have only seen the engine get there a few times. It may be that I can pull some fuel out of the map.
What is nice about the AEM is that you program in PSIa and RPM. My tables are setup to allow me to get to 14k' of altitude to sea level. If one is never going to go to either "extreme", one can just change the scaling to gain better resolution in the maps. Or, conversely, one could set up the "B" map for altitude over some user selected value. You would need an onboard altimeter though...
As an FYI, the Factory PCM operates via PSIa. In both the cases of the F/IC and the PCM, at initial power up, Zero RPM, look at the standing MAP value and select the starting fuel/ignition points in the map based upon that value. Auto correction for altitude.
A popular myth is that you "have to run the high Octane fuel" in a forced induction engine. No, you do not. You have to adjust the timing for the fuel you have on board. My "B" map (which was originally going to be for E85) is set up for 85 Octane. On the 85 Octane, the Heep will still out run any other XJ in town that still has a 6 under the hood. I qualify this as there are more than a few V8 XJs running rampant around here.
Will you get more performance out of the higher Octane? Sure you will but, it is not a requirement.
I know, 85 Octane. You guys down where there is actually air do not know about this stuff. But, up here, where the O2 is less, we run lower Octane across the board plus it is at least 10% Ethanol in the Summer and 15% in the Winter.
And as a final rant, Boostec is a Distributor for Sprintex. That is all it is and no more. There isn't a soul at Boostec that actually understands modern fuel injection or how it relates to a supercharged engine. The use of the AEM was lifted from me by a person that works at Boostec and he went away from my house with a very incomplete understanding of the product. Had I known that he was going to do what he did, I would not have invited him to come over to the house. At the time, I thought he was a friend. Guess not...
