Ya-Hoo!

[F-127]

Question time. So here I am comparing between files SD shifting and the OBS shifting parameters and I came across TV maximum for the different shifts. The SD TV max for 1-2 is a whopping 40psi higher than the OBS, which was 47. SD max for 2-3 is over double, and 3-4 is 39 psi higher. Bumping up the indicated torque just slightly and using the TV slope and offset I'd be hitting the max fairly quick. Is there any reason I couldn't use the SD values for the maximums? Maybe the higher max was to allow for adaptive shifting, which I think I read could change up to 20 psi?

[907DAVE]

Pretty sure that the adaptive stuff can do up to 30 psi, as far as the reason for the differences between the two I couldn't tell ya.

[F-127]

Note:below is about a 97 7.3 auto
Well, here I am, finally getting more down and dirty with trans tuning, I had basically been using stock shifting except for a street race file I came up with. I hadn't paid too attention to the exact shift points; I didn't make the correlation between speed in the files, and actual speed for the shifts. I only made a very few changes, just moving something up or down. Well I check and actual shift points were 20% higher than programmed shift points. So I make the change to get the shift points to match speed, actual and programmed. Take a short test run, seems OK, but I really only took note of the speed for the 3-4 shift, and its dead on. After some more driving, I find myself thinking: man, the TC is locking awful soon. I do some more looking, now TCC is locking 20% under programmed speed. I don't remember how the TCC acted before I made the change to 'calibrate' the speed of shifts and actual(used N over V). I may try my previous files just to see how the TCC engaged before as I can't remember. Seems that I'll have to live with only having one of the shifting correct: either gear shifts or converter lock/unlock.

Initially, I had thoughts the PCM might grab a recalibrated speedo(by the procedure of grounding under the dash), but it doesn't not seem to do that. So then I was thinking that engine RPMs were used, but how would that work to determine speed when the TCC is unlocked? So does the OBS get the speed signal for shifting from the VSS in the diff? If so, then I can't figure out why the TCC lock/unlock would be different than gear shifts in terms of speed actual to speed programmed. Make any sense? If you think this "" about me I won't feel bad.

[907DAVE]

VSS signal on the OBS comes from the PSOM (Programmable Speedometer Odometer Module), and is located in the cluster itself. The PSOM receives a speed sensor signal from the DSS (Differential Speed Sensor), then converts it to an "8k pulse per mile" signal output.

[F-127]

Thanks Dave. I went back and tried the previous files I was running. Both gear shifts and TCC lock/unlock were about 20% over programmed speed. When I adjusted the NoverV to get the actual shifts at the programmed speed, I got the shifts dead on, but for some reason the TCC lock/unlock dropped to be 20% below programmed speed. I might have double check that again, but I know I had the TC lock for third on me at under 25 when I thought it was going to be dead on like the shifting and happen around the stock 29 it was supposed to. That's what really warrantied the in my last post.

[F-127]

New beasts to tame. 285/200s. Presents two challenges. All new files to work on for me, as well as swapping some maps to get the former 238/100s in a SuperDuty. Actual injector swap should be complete this weekend, I'll probably be working on new files this week instead of classwork. Then about a week later a sledgehammer should be showing up. Good to have an older brother to sell the hand-me-downs to.

[907DAVE]

[Power Hungry]

OBS Shifting strategies are some of the trickiest to deal with. Superdutys seems to have better manners.

With that said, I'm not sure why the TCC strategy is acting a fool. That's pretty odd. If you have time and want to send a file over, I can take a look and see if there's anything we've overlooked.

Take care.

[F-127]

Awesome offer! I've sent an email. Thanks Bill.

Another note, saw the goods with my own eyes tonight:




Not new, but it'll do.
Kinda made me smile. "For organized race, competition use only"
I see them running on the street, and with fair manners as well. Just give me a little time.

[907DAVE]

They can run juuust like stock until you really want to move, just takes time.