Another stupid d-jet question:, Related to a new 2.1 tune: defining terms- what constitutes "part-load vs full-load" and other mysteries |
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Another stupid d-jet question:, Related to a new 2.1 tune: defining terms- what constitutes "part-load vs full-load" and other mysteries |
DRPHIL914 |
Nov 29 2021, 08:06 AM
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#1
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Dr. Phil Group: Members Posts: 5,768 Joined: 9-December 09 From: Bluffton, SC Member No.: 11,106 Region Association: South East States |
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 |
emerygt350 |
Dec 2 2021, 09:09 AM
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#2
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Advanced Member Group: Members Posts: 2,147 Joined: 20-July 21 From: Upstate, NY Member No.: 25,740 Region Association: North East States |
I bet you are a bit low on your timing. Have you tried adjusting your timing till you get a good idle (850) and giving that a try?
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DRPHIL914 |
Dec 2 2021, 02:29 PM
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#3
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Dr. Phil Group: Members Posts: 5,768 Joined: 9-December 09 From: Bluffton, SC Member No.: 11,106 Region Association: South East States |
I bet you are a bit low on your timing. Have you tried adjusting your timing till you get a good idle (850) and giving that a try? was at stock 27 degrees@3400rpm and verified before slightly increasing it which helped but i have to go back and recheck it at idle too and see what its at at 900rpm - one other factor thats going to effect that is the richness/leaness at idle, thats why the true AF at idle matters too. hope to get to check it tonight. |
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