Defuel amount mm3 (how much should it drop)

[GeneralTJI]

So now that I can log my truck finally I have been going over things in detail.

Getting shift points right on target (well... they are never exact I'm finding). Vane position tweaking via maf flow etc.

Anyway...

How much reduction in mm3 should the truck see during a shift? My truck doesn't defuel hard, almost wondering if it's actually enough.

What's a ballpark number in reduction of fueling during the shift?

Just want to make sure I'm not killing my Allison that much faster...

 

[SSchmi5519]

The mm3 value is simply a reference. Look at the pulse in the corresponding rows to alter the defuel.

 

[bluessmax]

The mm3 value is simply a reference. Look at the pulse in the corresponding rows to alter the defuel.

x2 and torque reference

 

[GeneralTJI]

Right I see what your saying--> depending on what kind of pulsewidth I'm calling for the mm3 drop during a shift could be a lot or a little.

I noticed my mm3 is dropping around 20+mm3.... although that puts it down in a place where I'm not calling for real extreme pulse... basically it's dropping from a pulse of about 2250 to about 1850-1900.. that still seems too high to me? Especially considering it's not even cleaning up that 2250 so actual power drop is even less than it appears looking at pulsewidth. Should I rework my tune to have to drop more pulse during shifts?? (stock trans)

thanks for the input!

 

[SSchmi5519]

A smooth shift is a good shift.

Too much defuel you will feel the nose drop.

Too little defuel RPM will surge before a shift, or feel like it is "slamming" into the gears.

 

[GeneralTJI]

I think once and a while I was getting a tiny surge on some gears... so I did some tweaking to some maps and it's defueling slightly more now. Feels pretty smooth. The rpm curves during the shifts on the logs look smoother as well.

 

[SSchmi5519]

Good, it sounds like you are getting the shifting dialed. :thumb:

 

[GeneralTJI]

Being able to log my truck has been very useful :rofl:

I had been shooting from the hip all these months until just the other day when I got an updated version of HP that actually logs. Truck ran pretty well before but some little tweaks have proven to make a difference.

Thanks for the input too btw

btw, I realize every truck is different, and everybody usually has a different setup. Is there a certain amount (%) of pulsewidth reduction I should be shooting for during a shift. Anything even ballpark just to make sure I'm on track. I feel that the truck is shifting pretty well, but I like to compare/check my work when possible.

 

[DIESELMAFIAPER.LB7]

curiuos i need to tweak this as well what tables are you guys modifing on lb7s torque limited injection quanitiy? or...

 

[pavetim]

i'd like to know also. What maps or parameters did you use to monitor your defuel?