Hello guys,

I hope you are all doing well.

On the MEG1.1 side of the fence, which is fairly similar to the ME7, hence my question, there's a debate.

I'm of the opinion that LTFT applies as correction factor even during open loop, it just isn't updated like it is in closed loop control but used "as it was" before transitionning to open loop. My reasonning is that LTFT is used to correct for ageing components, slight variations of specs out of the box and other related issues, so while it is learned during closed loop by reading the o2 sensor (and sometimes even separated between idle, low load and mid load on our specific ECU) and by transfering STFT to LTFT to make the STFT's variation smaller and smaller, it would make zero sense to not use that adaptation during the most potentially damaging phase of the engine's operation.

I've seen so many posts online of people saying open loop is just fixed table ignoring everything etc... But I felt like they were just not understanding the implications of what that meant. Because a lot of things are correcting open loop behavior (to control for IAT temp, knock etc...)

I've used my own DIY remaps on this ECU for quite a long time and have used "equivalent" 222cc/min injectors instead of the 188cc/min OEM ones without a single issue (while transitionning from sp98 to e85, I used a 3.0 bar FPR instead of a 3.8 bar to test things out before, injectors are really 255cc/min at 3.8 bars of fuel pressure), I made no adjustment in my map as the new injectors were internally the same as the OEM with less restriction (something well documented by the french youtuber UltimateMaking that explained that bosch has very few different injectors, but just uses restriction at the output to spec for a defined flow, so a given injector will be used accrossed dozens of application by just calibrating the nozzles) so dead times were essentially very similar.

I observed zero issues and stft/ltft quickly ironed out the fueling at every RPM/Load I've tried it. I ran it like that for 100km or so before fully switching to e85 by putting the 3.8 bar FPR back in resulting in a going from 188cc/min to 255cc/min and -0.8%LTFT on e85 (which is why I used specifically calculated those injector, to hover around 0% ltft on full e85). However, a tuner online said that using even a 10% bigger injector with similar construction will result in absurd overfuel at open loop, which I don't think is the case.

TLDR : Does LTFT apply to open loop ?

Thank you very much !

Tim