VF tuning collaboration and BS

If you don't want your truck to use sixth gear put your shift points to 255.999 for all values on five to six upshift.

 

Could you make a premium version?

 

It is as I explained a long long time ago that it's not a true atkinson elimination, and the tune is modified by changing the calculation of cylinder filling to throttle angle, which changes the calculated cylinder volume.Not the valve low VVT range / targets themselves.


There is a table "Calculated Cylinder fill" which is the ECUs method of calculating what throttle % = a cylinder getting 100% airmass. The axises are "raw" because the conversion factor is currently unknown but it is by throttle v RPM.
Play with it, and you can see the dramatic effect it has *in* this lower RPM range where atkinson *would* normally be at.

ignition timing atkinson compensation is just a change in ignition during Low intake VVT advance. It's not a representation of the actual filling of the cylinder or anything. it's just another table that compensates ignition, like the dozens of others.


if you wanted to make a *true* atkinson eliminated tune, you need to get rid of the low VVT range (intake VVT) and retune the exhaust VVT as well (retard) otherwise the engine will run terrible.

 

@Mooseditty17

Thank you, Sir. Being a newbie, when you indicate putting the shift points to 255.999 for all values on five to six upshift, is this the correct table you're referring to to insert those changes? And, out of curiosity and wanting to learn, what does the value of 255.999 represent? What do the values currently in this table represent? Again, thanks for your help and assistance.

 

That table will work. 256 represents speed in kph. Basically the truck can't reach that speed so it will never shift. All the numbers in bold represent your accelerator position. The non bold number represents speed in kph. Why are you not letting the truck use sixth gear?

 

@jc63
Primary upshift 5-6 is the map I use. The one you pictures should work as well. What @Chadr7858 is spot on. The gray values are degrees of accelerator angle and the values you changed are how fast the truck needs to go at that given angle before truck will upshift.

@Chadr7858 he probably doesn't like trucks inability to really hold 6th gear. Mine doesn't do it well either. Even on a stock 2.0 map. Weight, tire size, and gearing are all against us for a second overdrive. Up to 65 my truck usually gets better mileage if I keep it in 5th. I live 45 minutes from the nearest interstate... So 6th for me, is dedicated mostly to 65+ Even then it doesn't like to hold gear as well as it should. When you make it hold, seems very bogged down and mileage suffers to the point 5th at higher rpm and lower load values are more efficient.

 

Sounds like y’all need some 5.29s

 

Thinking so...

 

6th gear everywhere with them lol

 

33s or 35s?

 

@jc63 I hated 6th, mostly because it would require a double downshift to 4 at the slightest hint of resistance. I’ve got my minimum upshift speed set to 74 now. Works much better, downshifts to 5 if needed. No effect on mpg for me.
PS the speed values are much closer to mph. They are definitely not kph.
PPS this map is only one part of the shift equation. Engine torque and throttle position also play a role in ways I don’t yet understand. But you can do a lot with just this map.

 

Yes.

 

LOL

 

@Mooseditty17 @Chadr7858, Thanks guys. I was going to try and describe my need to lock out 6th in response to Chadr7858's question but couldn't quite get it right. The rationale, however, by Mooseditty is spot on.

 

Yes

 

Will it still be included on one of the final performance tunes you also spoke of a long, long time ago?
Appreciate the explanation for Atkinson elimination.
Is the "Calculated Cylinder fill" table also the remaining solution to the torque converter mystery?

 

It's planned to be the VVT table when you're in 4low, where atkinson doesn't really make any sense

unrelated to the torque converter

 

@OVTune Does modifying fuel injection split % require any other changes to operate?
IE: Modifying % split towards more DI at high load / rpm and more PI oriented at low load / rpm

 

@OVTune Lastly... for now:

What does changing the ACIS low breakpoint from 25600.78 to 36600.78 do?
Leaving all other values equal...

I've also seen variations in the high break point from 25600.78 to 0.78125?

Any insight on this would be appreciated.

 

@Vlady

when you changed expected and control airflow, what benefits did you find?