Quote:
Originally Posted by arinkuddy
I've looked at duramax stock files before and I wouldnt know where to begin with them. Quite a bit more to take into account vs an 06 cummins.
Isn't % throttle a relatively useless metric to use? The amount of fuel is a function of pressure and duration which would equate to some quantity of fuel. Increasing pressure or PW would make less throttle put more fuel, seems that way on cummins anyway.
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The LMM starts
tps%/rpm=TQ
Tq/rpm=mm3
Mm3/rpm= rail pressure
mm3/rail pressure=pulse width
Mm3/RPM=timing (pilot timing is similar though has additional factors contributing to it such as ECT, TPS, RPM, and time between pilot/main injection(s))
Outside boost/MAF/map table these are probably 75-80% of the tune
Educated gues Cummins did something similar.. Haven't looked a Cummins tune in for ever.. Lol
I have yet to see two factory tune trucks of same year and engine with the exactly same tune when you plot it out..
Throttle % and TQ/rpm table are the proverbial linkage between your foot and the carburetor. And pretty much what all the other tables go off of for basic info.
Yes fuel is a function/result and RP and PW. Increase RP with same PW equals more fuel.
If you go from say 2500rpm is 20000psi RP at 50mm3 to 2000rpm and 30mm3 with nothing else changed good chance to have some surging.. That's alot of fuel alot sooner
Here is OEM stock LMM rail pressure table
And what I'm currently running
I can tell you the latter rail
map sucks on a relatively stock tune..
Only downside I've found to higher rail pressure is fuel return, gets hotter faster especially in summer, wouldn't surprise me if Cummins has a high return fuel temp limit in which is derates the engine.