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Thread: Low Boost Fueling MAF question 6.7 Powerstroke

  1. #21
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    For sure I try to leave low mid throttle alone it would also shift weird on my last column of torque to fuel I?ve recently tried 120 mm3 at 600 Rpm and 130mm3 on but I?ve seen one # across the whole column unlike stock that?s all over the place
    How much mm3 have you ever logged

  2. #22
    Advanced Tuner JaegerWrenching's Avatar
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    Quote Originally Posted by Jeffrey Kavney View Post
    For sure I try to leave low mid throttle alone it would also shift weird on my last column of torque to fuel I?ve recently tried 120 mm3 at 600 Rpm and 130mm3 on but I?ve seen one # across the whole column unlike stock that?s all over the place
    How much mm3 have you ever logged
    I see 168mg of fuel WOT from 1800 RPM and it drops to 158mg by 3400RPM. The reason a stock Mg of fuel goes up and down while going left to right on the fuel map is because of things like cam profile, compressor efficiency and also emissions targets. Think of it this way, If boost stayed the exact same during a WOT pull across the entire RPM range, your fuel map should look like a hill and the top of that hill is where your engine makes max tq. You will need and use the most fuel where the engine makes Max TQ, this is always the same for every engine gas or diesel it doesn't matter. This is also where injector PW would be the highest if fuel pressure remains the same. So everything to the left or right of max torque should have a constant decline in fuel amount to maintain the same AFR. This is because of the way engine's operate and move air through them. The cam/engine profile will always pick where max tq happens, this is predetermined and set in stone after an engine is assembled. It never changes unless you're doing something like adding boost as RPM rises, which is common to keep tq/hp increasing! But The 6.7L diesel has Max torque occur at 1800-2000RPM, again this is because of the cam and engine's VE or volumetric efficiency profile. The only reason you see a consistent amount of fuel left to right on any fuel map in any tune is because boost is climbing with RPM or the tuner doesn't care about things like smoke or keeping the AFR constant throughout the run. Jeffery the biggest piece of advice i can give you is i highly suggest you thoroughly understand the relationship between TQ to fuel amount and how cylinder pressure all play together. Remember when i said 1000ftlbs of tq @1500PM is the same amount of HP as 500ftlbs of tq at 3000RPM? This means we can have half the amount of air and if maintaining the same AFR half the amount of fuel in the cylinder per combustion event at twice the RPM to produce the same amount of HP! This tells us HP and tq have a linear relationship and we can derived one from another. This also tells us that cylinder pressure has to be equal to torque, it's our piston's driving force and what we ultimately care about. From all this we will always know Max tq happens when we get the maximum amount of air and fuel together in the cylinder to produce the highest cylinder pressure. It's late, i hope this is written well enough and hope it helps, i'm to tired to proof read it.
    Last edited by JaegerWrenching; 01-16-2020 at 02:44 PM.

  3. #23
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    I see what you mean now on my Lambda target should I leave that alone till I get fueling down I have been meaning to upload my log file I had went through a break up last week and am disorganized don?t even have WIFI yet lol
    Some days I?m glade I tune my truck others not so much
    I appreciate you helping me out this limiter is getting old fast the most fuel I?ve logged is 75 mm3 total I have to say I would have thought by now I could made a tune that?s not 100% garbage

  4. #24
    Advanced Tuner JaegerWrenching's Avatar
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    Quote Originally Posted by Jeffrey Kavney View Post
    I see what you mean now on my Lambda target should I leave that alone till I get fueling down I have been meaning to upload my log file I had went through a break up last week and am disorganized don?t even have WIFI yet lol
    Some days I?m glade I tune my truck others not so much
    I appreciate you helping me out this limiter is getting old fast the most fuel I?ve logged is 75 mm3 total I have to say I would have thought by now I could made a tune that?s not 100% garbage
    I need to look at your tune to see what it's doing. I can't help without it.

  5. #25
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    I?ll email you the tune now!!! I found fuel temp was set to stock and anything above about 80F would limit my torque I would greatly appreciate it
    I got a buddy who has been hinting around for a loap tune but I?m second guessing my tuning skills at the time
    I loaded my tune after spending a few hrs just checking what the hell is limiting me if I almost loaded my stock tune and tried to read the canned SCT tune

  6. #26
    Advanced Tuner JaegerWrenching's Avatar
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    Quote Originally Posted by Jeffrey Kavney View Post
    I?ll email you the tune now!!! I found fuel temp was set to stock and anything above about 80F would limit my torque I would greatly appreciate it
    I got a buddy who has been hinting around for a loap tune but I?m second guessing my tuning skills at the time
    I loaded my tune after spending a few hrs just checking what the hell is limiting me if I almost loaded my stock tune and tried to read the canned SCT tune
    A quick look seems to be your forced mono turbo mode holding you backForced Mono turbo.PNG set this to 1100 from 0RPM to 3700RPM this is holding all your fueling back,

  7. #27
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    What a difference I drove all day today with a smile the whole time you?re the man big time 💪🏻👍