ECU Tuning 2
Next up is the VTEC open loop tuning. Thanks to
@MotorMouth93 's excellent tuning script, this process has been made much easier. However, a leftover artifact from his tool is that the program will only adjust cells where there is enough sample data. The result is you end up with a "patchy" or "spiky" fuel map where the program made changes, but left them alone in the cells where there wasn't enough data. Thus, it's up to me to "smooth" the map using the changes made as a guide. For example, if the program reduced fuel by 3% in three cells, its reasonable to assume that some reduction is needed in adjacent cells. I tried to follow the curve of the map.
The main issue I'm seeing is that the map is generally too rich under load state 69.02, which makes sense since you're typically not using VTEC at less than 69% throttle unless you're on a race track. Thus, I reduced the entire map below this range by 10% to have more of a smooth ramp up to the actual VTEC range used by the car.
We can see that the shape of the curve has a torque peak at 6800-7000 rpm and then actually falls off. However, since I cannot log any data higher than the 75.29 load state due to my altitude, the "fall off" might be artificial. This indicates that my current set of mods (cams/big intake valves) appears to have shifted the torque curve slightly higher than the factory range of 6400 rpm. Or put another way, peak torque comes on later with this setup. If we examine the OEM fueling strategy, peak torque starts at 6400 rpm:
Final form (for tune V2.6, anyway). There is a big jump from Load 69.02 to 75.29, mostly because I've been doing WOT street VTEC logging and WOT at this altitude is 75.29. I may need the dyno to refine the lower load bands...
