Shift Schedule

[Shaw]

Whats the trick to get the shift schedule to match actual vehicle speed. Example - I have my 3-4 shift flat lined at 41 mph and it will shift to over drive around 50 mph.
Ive tried to change the Tire size but it doesn't make any noticeable difference.

What ever it is, it is also affecting the Torque converter lock up in the same manner.

What did I do wrong :shrug:

[cleatus12r]

Nothing wrong.

What year is the truck? Is it a SD or OBS?

[Shaw]

I guess that would help -

2000 SD

[cleatus12r]

Yeah, the SD truck stuff is all over the place as far as shifting goes and although it's all relative, the shift points themselves actually don't coincide with actual road speed too well. I love the OBS trucks for that. Usually, everything is within 2 MPH on those.

The SD trucks have anticipated shifting strategies and the like that really mess with what is actually going on.

[Shaw]

So even with the anticipated shift shut off its still going to be all over the place? If I get the emulator would it make dialing in the shifts a little easier you think?

[907DAVE]

Have you tried adjusting the 3-4 Cruise instead of the 3-4 shift schedule?

Somehow those two got switched in my definitions.

[cleatus12r]

It's not just your definitions, Dave. I don't think they're "switched" per se, but it's just the way they're labeled; there wasn't exactly a manual to follow when Bill was making the definitions.

I adjust both of them the same though.....

[Shaw]

@ Dave
I set both of them the same. I was only using that particular definition for example. I have the problem with 1-2 2-3 3-4 and down shifts too. The trouble is when I try to adjust my down shifts I'm just shooting in the dark since none of the mph correspond to any of the shift points. Because of this it takes multiple times to figure out what mph a point is at. Also, its not 10mph across the board difference. Its gets smaller as the speeds lower, its not a constant.


@ Cleatus
Why do you think it makes no difference when I change my tire size rpm? I would think that should do something?

[Shaw]

Will do and Ill let you know.

What does N over V stand for? What is that parameter?

[Pocket]

I fought with the same thing for a while. Even came up with a strategy for a tiered shift schedule (graphs looked like stair steps). It worked, but I learned something in the process. This is just my viewpoint, but it seems the SD's are far more sensitive to pedal input than road speed when it comes to shift points.

Once I took that approach, shift points became easy. Don't even have to use the tiered shift schedule anymore.

Sorry, nothing technical there. Just do what I did, and start disregarding road speed and focus on your pedal position. When you do that, start thinking about the fueling with your tunes. The more fuel you bring on early, the less throttle input you have to play with in regards to shift points.

Not sure if that makes any sense to anyone. If not, let me know and I can try to clarify.

[Power Hungry]

Will do and Ill let you know.

What does N over V stand for? What is that parameter?

eNgine RPM/Vehicle Speed

[cleatus12r]

My bad. I should just quit this.

Today is not a good day.

[Shaw]

Pocket - I think your right. Now that I think about it, I started noticing the issues after I made changes to the A/D counts in the Mass fuel map?

How do you guys figure out your down shifts when setting it up that way? It just would be so nice to look at the chart and figure it out by RPM / vehicle speed and make it do what I want it to.

Do any of you have the issue with your torque converter locking at a different speed then what you tell it to?

[Power Hungry]

There are several things controlling torque converter lockup that make it a bit difficult to pinpoint. There are time delays, load calculations, trans temps, and even RPMs that can delay or even prevent a lockup from occurring. Because of this, there is no clear-cut way to control converter lockup. We can usually finesse the values enough to achieve what we're looking for, but sometimes the ECM has a mind of its own.

[907DAVE]

It's not just your definitions, Dave. I don't think they're "switched" per se, but it's just the way they're labeled; there wasn't exactly a manual to follow when Bill was making the definitions.

I adjust both of them the same though.....

Yup, wasn't a knock on PHP, just something I fought with for a bit.

I too am now in the habit of making both the same, even for the 4-3 shifts.

Shaw- a emulator is the shiz!

I learned more with that damn thing in a week then I did in a entire year! If you can swing it, I would get your hands on one.

[Shaw]

Cody - your post you made is missing about changing the N/V. Anyway's I found that when I changed it to 52 the shift and converter lockup went the wrong way (making the map further off) Tonight I will put a lower number in and see if it moves it towards what Im looking for. I think this might take care of things.

Bill - I seem to have the converter pretty much locking constantly when I want it to. It just doesn't match what the map mph says. the map says 30 but then it doesn't lock till 39mph actual. If I put 21mph in the map it will lock around 30. Not a big deal, just confuses me when I try to figure it in with all other shifting.

[cleatus12r]

Cody - your post you made is missing about changing the N/V. Anyway's I found that when I changed it to 52 the shift and converter lockup went the wrong way (making the map further off) Tonight I will put a lower number in and see if it moves it towards what Im looking for. I think this might take care of things.



Oops.

Thinking one thing and typing another..... :notallthere:

[Shaw]

It worked :happy-dancing: looks like the magic number was 40. Thanks for the help!!!