Another stupid d-jet question:, Related to a new 2.1 tune: defining terms- what constitutes "part-load vs full-load" and other mysteries Options

[DRPHIL914]

calling all d-jet masters !

OK so yes, ive read Anders etc and maybe missed it along the way, but
how or what constitutes a part-load condition?

I am trying to get my d-jet MPS dialed in on the 2.1 build. and it had been running really well, but just a tad lean still, so after going back and reverifying my timing and other settings, checking plugs aftera 750 mile trip, its really close and realizing i was probably a bit low on the fuel pressure i made that correction and then set out to do some local highway driving to test it out, and really felt good, but maybe a bit rich at low end, idle and what i was thinking would be part-load.

BUT i think i over corrected on the MPS and now i went from being in the 12-12.5 range at idle and also cruising at 3000-3400rpm, i now am running light at about 14 on that mid-range cruising. it is good on WOT so i dont want to mess with that(full load stop) .

i should have left well enough alone because i will probably be a bit heavy at idle and low end with this motor, due to a more performance minded cam profile etc.

point is, what is part-load? if i am reading my AFR meter , lets say at 3000rpm- 3400rpm and cruising on the flat, that would be part- load condition correct? so i dont want to make it more rich at cruise or on WOT, so how can i isolate the mid range or par-load to enrich it with out messing anything else up. i already messed this up trying to just lean it out slighty and over corrected.

if i adjust the inner screw by itself it changes both part and full load.
the outer screw in will richen part load i believe lean out full- load.
the Anders chart doesnt really address it.
- also i feel i cant really get idle right, it seems too rich but that might be the way the motor will be, not sure.

the MPS is a rebuilt one with Tangerine kit and adjustor screws, so easy to access and adjust using the Tangerine tools.

I may be at the point of just going dual webber with 44 IDF's, and forsaking the d-jet - OR a more modern programable EFI...... i just dont think i am getting the most power out of this motor that i should or would with better air intake and A/F mix.
intake is somewhat restricted on a stock d-jet and the injectors can only give you so much fuel. i did see somewhere anders wrote that the stock set up could support a build up to 2270 even with the proper changes( not sure what that means either),

anyway first question is - part load definition. then how to proceed to get this mid-range or par-load adjusted into a better mix with out making idle even more rich(or WOT either)

Thanks for the help.

Phil

[DRPHIL914]

here are 2 plugs, this was before input them back in and then attempted to adjust the setting and messed it up.
- also my head temps and oil temp readings i think are accurate and are pretty good , not sure i am believe or knowing how accurate the AF readings are, it the plugs should give a good idea of where i was.

[emerygt350]

Those look good to me. I just did a deep dive into previous threads on this topic. Very interesting. Things I dredged up from the past... (may just be urban legends but I doubt it)

1) Air-cooled engines like it richer
2) 14 and less seems good
3) 12 at WOT seems good
4) Don't go driving around at 15 particularly while in 5th gear at lower rpms.
5)13.5 at idle is common and seems like a happy place, some people go richer.
Let the engine decide what it likes (assuming you aren't going north of 14 at partial load or 13 at WOT).

[DRPHIL914]

Those look good to me. I just did a deep dive into previous threads on this topic. Very interesting. Things I dredged up from the past... (may just be urban legends but I doubt it)

1) Air-cooled engines like it richer
2) 14 and less seems good
3) 12 at WOT seems good
4) Don't go driving around at 15 particularly while in 5th gear at lower rpms.
5)13.5 at idle is common and seems like a happy place, some people go richer.
Let the engine decide what it likes (assuming you aren't going north of 14 at partial load or 13 at WOT).

i agree with that , it seems to be where we want to be. i do think i am a bit rich at idle and i cant adjust the ECU more than it is. i may have to settle for that. I am more like 12.5-13 at idle. just a very low idle too, i have to open up the idle air valve to keep it from bottoming out once warmed up. it had a good cold idle.
i should have left well enough alone. going to work on getting it back to where it was.