could also have been how far they were from the corresponding part throttle shift points, either way I needed to fix a bunch of stuff now that I have driven the truck and am getting a feel for what it wants. here is my new shift map, noy much stock about that trans tune, maybe the downshift wot values...
Hi Mike,Originally Posted by Big Mike
Joe you know I'm in no way trying to step on your toes as you are the master with this stuff but those shift tables he posted are stock. And every truck based 4L80E tune I've ever seen have the downshift speeds higher than the upshift speeds so I wouldn't say that is the issue. Suppose it makes sense too. It can't downshift unless it already upshifted first, correct?
No worries, I welcome all comments, I'm open to learning new stuff...
hmmm, so trucks have the WOT downshift set higher than the WOT upshift (along with Throttle Kickdown tables not set to 100%TP).
when WOT downshift is above the WOT upshift, then when the operating point is between these there is a conflict, and this is further compounded by the Throttle Kickdown not being 100%TP...
I suppose then that WOT shifting is accomplished by the operating point crossing the non-100%-curve on the Throttle Kickdown tables... in the colored graph in post #1 imagine that the WOT shift points are where the red and green curves hit the right-hand-side vertical axis (100% on the horizontal axis), and that the green point was above the red point... so the blue curve would command the WOT upshift when the MPH crosses from below the blue curve to above it (moving upwards along the RHS vertical axis)... interesting way to control WOT up/downshifts, I didn't think of the Throttle Kickdown table being used to command an upshift.
Last edited by joecar; August 18th, 2012 at 08:59 AM.
Still doing it...
Now I am really stumped, Still doing it with my latest changes, Should be the shift curves as above but here are the log and tune from the latest run. Around frame 246 it does a 1-2 shift just rlling around then after some throttle it shifts back down and hits 6000 until I lifted. weird...turbo_axle_80shift points.tunLog_0102shift.efi
Hmmm, weird... I'll take a closer look tomorrow.
Gracias!
Hmmm...
Try setting D1206 to 95% and 85% and D1207 to 95%.
When you changed any of the speedo parameters (Hxxxx) did you apply the shift point correction...? [ I'm grasping at straws here ]
Click on any of the MPH cells in any PT shift table, and look at the bottom of the tunetool, it shows the RPM that that MPH corresponds to in each gear...
is the correct RPM shown for each MPH...?
manually calculate this and see if it agrees with the tunetool:
RPM = MPH * 336 * GR / TD
where:
GR = overall gear ratio = transmission ratio * axle ratio
TD = tire diameter in inches
If it does not agree, then that is the problem.
No problem, I'm out of straws to grasp here so I'll see what yours turn up. When i did the axle swap i changed the ratio and the rev/mile so it should be good and when I manually calculate it checks out, comparing to my log it's 200 rpm higher which would account for slippage.
My tps only goes to ~90% pegged wot, It is the wrong type for this vehicle and it is mounted on a carburetor baseplate so the range is a bit off. I figure I have adjusted for it but maybe not. Thinking about it now, Why do I even need WOT throttle settings? I can figure out where my rpm is at for each mph per the log and just put that into the part throttle tables at 90% throttle right? Then do as you say and set throttle % for WOT above my wot tps and it will be unattainable and never be used.
Any flaws in my logic? I have a feeling the issue is moving from the pt tables to the wot settings and back again but not sure why from the way i have my tune. Maybe I will try adjusting my pt tables and setting 1206 and 1207 to unattainable and see if it keeps acting up in pt mode.
Do wot shift speeds need to be above part throttle highest value? IE if my high end part throttle 1>2 shift speed is 50 but my wot shift mph is 40 and 5300 rpm could that be my problem?
That shouldn't be the problem because the WOT are enabled when D1206 is met (and D1207 is below D1206)...
but try making them the same anyway (this is how I always set mine).
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