I was going thru some datalogs, and realized that it was calculating the secondary injector duty cycles to be completely ridiculous numbers (like 40,000,000% or something). Im assuming that this is just a problem with the formula for the secondaries when using staged injection, since the PW's are fine (the same as primaries when they're on, so no problems there).

I also wanted to see what other people tuned their cruise to, AFR wise. mine hangs around an AFR of 15:1 at 50 kpa up to about 12.5 - 13 at 100 kpa. What is stock? (i have an S4 TII, but any would be fine, since its basically running as NA up to 100 kpa)

Also, when tuning for fuel economy, I try to tune to be able to use the minimum pressure and still maintain constant speed. Is this a good way to do it?

Thanks

 

good spot on the secondary duty cycle ... I usually only keep duty cycle 1 up and it seems to drop by the correct percent when staging kicks in (never paid attention to the secondary duty, but iirc it does do something weird).

I am not sure about stock, but 12.5-13ish at atmosphere sounds in the ballpark. For light cruise I try to aim for the lowest possible map(45-50ish) and lowest possible rpm in 4th or 5th ... low 15's are good imo ... I have tried upwards to almost 17 and didn't notice much of an improvement in fuel economy, however bringing timing way up there did help.

HTH

 

Ok, good. Right now im getting pretty bad fuel economy (about 14-15 mpg mixed, but with the shorter turbo gearing), and would like to aim for 20+. I think the timing in cruise is pretty conservative, but I dont really have anything to go off of. This is the msq that i'm driving off of now, and it works pretty well. There is a bit of weird stuttering going on that i can feel/see/hear under light load when cruising, but it goes away at higher loads, speeds, and at idle.

 

after a quick peek ... imo your timing is a bit too conservative (split too) ... I think the stuttering may be tied to this(unless you have accel kicking in at cruise or something). I'd kick in your overrun settings when you feel comfortable with ve and accel ... this improved my mpg greatly ... (I think I avg'd 22 last tank)...

 

I wasnt sure about the overrun settings, since they seem to completely cut fuel, reducing a source of lubrication (i still have the OMP, but the fuel does it as well). I thought that was the reason that most of the time the rear rotor goes, cause thats the one the stock computer cut fuel on for overrun. I am just a little concerned about that, especially since im at just about 1000 miles on a new rebuild.

Oh, and thinking about the duty cycles, for the secondaries they will either be 0 or the same as the primaries since they are either off or on the same amount (except when just turning on, but yea), so it doesnt really matter if their log doesnt work

 

If you stay out of boost I'd think you should be in the low 20's mpg. For timing recommendations, there's lots of good info in this thread:
http://forum.teamfc3s.org/showthread.php?t=41915
You are correct, there is a bug in the duty cycle calcs for bank2 when using staged injection. Just ignore that value. As you say, it's either zero or equal to primary duty cycle.

 

oh, that thread is good, and very pertinant. I hadnt come across that one before. New timing map, here I come.

I think i may have found the cause of the stutter too... one of the cells in my split table was negative, and it was right around where i noticed the stutter most often. Can MS even do a negative split?

 

Well, whether it was getting rid of the negative split, or bumping up sections of the timing map based on that thread, the car was running really smooth this morning on the way to work. No stuttering at all, nice and responsive, very nice. There was a bit too much fuel at 6 psi and around 4500 rpm tho (pegged the afr gauge at 10, gotta work on that...), but i'll work on that on the way home.