Shift Schedule

Shaw · #1 Mon, July 25th, 2011, 11:51 AM

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

***cleatus12r*** · #2 Mon, July 25th, 2011, 12:42 PM

Nothing wrong.

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

Shaw · #3 Mon, July 25th, 2011, 01:50 PM

I guess that would help -

2000 SD

***cleatus12r*** · #4 Mon, July 25th, 2011, 02:46 PM

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 · #5 Mon, July 25th, 2011, 03:25 PM

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*** · #6 Tue, July 26th, 2011, 01:24 AM

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

Somehow those two got switched in my definitions.

***cleatus12r*** · #7 Tue, July 26th, 2011, 07:49 AM

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 · #8 Tue, July 26th, 2011, 08:50 AM

@ 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 · #9 Tue, July 26th, 2011, 09:57 AM

Will do and Ill let you know.

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

Pocket · #10 Tue, July 26th, 2011, 11:35 AM

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.