Torque Converter Lockup

[68showngo]

So I've been trying to figure out the torque converter lock-up tables for a while now.. think it finally clicked and now I'm not sure if it's right because it seems somewhat simple.

Just for an example, let's just say I set the table to keep it locked in 3rd 100% of the time. Would it lock instantly after it shifted into 3rd like it normally does when it shifts into 4th? Would it unlock during the shift from 3rd to 4th on a setting like this? Is there any setting that will force it to stay locked during shifts? I would love the locked shifts, but after a talk with my transmission builder I think I actually want to stay away from them now.

Let's also say I set the whole table to stay locked the whole time in 3rd, would this affect anything wrong in other gears etc or does it really only kick in when it hits 3rd? I'm actually more thinking about setting it to lock quarter or halfway through third at WOT, but just want some ideas of what I'm looking at.

[icemanjc1]

It will lock when ever you tell it to. Problem is when you lock it up (at lower shaft speeds I'm certain) before 40~mph and reach around 40 to 42, you'll get this strange 3rd-4th locked then unlocked scenario all of the sudden (doesn't work). Won't hurt the transmission though. Try it, can't learn if you don't try.

[68showngo]

Ok I think I'll try playing with some things here soon. I've read the other transmission tuning topic so I've got a few little tips to work with.. I just didn't see much about lock-up in there.

[tinman]

I am playing with this and am having problems. I changed 2nd gear a little and could notice the changes but am at stock now. I would like get 3rd to lock similar to what it is like in T/H but I can't get it to do anything. I changed the axis of the TOPS to get the needed rpms to display then I changed the graph in the tables but nothing changed in performance. Acts just like the stock.????.

[icemanjc1]

Can you post a screen shot of your B4518?

[tinman]

B4518

12779

b4520

12780

[icemanjc1]

I would try reducing the axis points on the unlock table as compared to the lock up. About a hundred or so, see if that works.

[DoghouseDiesel]

Here is the recommendation I have with these lock / unlock tables.

First and foremost, you MUST know the output shaft speed that you you want this thing to shift at.

Do a set of logs that are recording the trans parameters. Gov pressures, TTVA angle, TOS, engine speed and throttle position.

Once you know exactly where you want it, it makes the adjustments a lot easier.

[tinman]

Rich, I used your excel file to figure the TOPS I want the tc to unlock at 0 throttle, and that is reflected in the unlock table. I changed the lock table to close the t/h table. I basically want the TTC locked above 30mph unless I'm heavy into the throttle at low rpms/speed. I haven't logged a full set of trans data yet, but I do need to. I am just dipping my toe in the water of trans tuning with something simple. I'm kinda waiting on my twins and then I'm going to get over to your shop an let you work your magic.