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Originally Posted by Neo187H
Awesome information in here guys, I'm glad this has turned into such a discussion. Despite the fact that I'm now more confused than when I began  .
My tuner is an experienced tuner, mainly with Hondas, but they have no experience at all tuning Nissans or Uprev at all. They have been on the phone with Uprev throughout the day so I'm ASSUMING that they have stuff like the K factor (not that I have any idea what it is ) covered but I'll talk to them further tomorrow.
Would stuff like the K factor affect the cars running throughout the entire RPM range? It currently runs great on the dyno up until the point where it starts to lean out up top.
A rather basic question but, what should the target AFR be? Years of fixing cars and I'm totally incompetent on the tuning side of things. |
The K multiplier is a constant value that models injector size and pulsewidth -- it affects injector ontime throughout the tune. To the best of my knowledge, the value typically needs to be chaged if you change injectors.
Target AFR is whatever makes best power with no evidence of detonation, and varies from engine to engine. Something on the rich side, most likely, as the extra fueling (i.e., running a mixture higher than stoich) is used to cool in-cylinder temps. Probably something around 11 - 12, but could be a bit richer (or leaner) depending on load, octane, ignition advance, CR, boost pressure, etc, etc.
If your guys have good general knowledge with tuning FI'd cars, they should be able to figure it out, at least to dial in a basic tune. Eventually somebody who has more experience with uprev and with this engine should be tracked down for fine tuning if possible.
The guys with more experience using uprev in particular and on tuning this motor in particular can probably give you more specific info...