I'm going to have my car put on a dyno at a car show on Saturday. When I had it dynoed there last year, the dyno guys were very impressed, but said it would have even higher numbers if the converter would stay locked.

I have made a tune that I plan to flash when I get to the show because it isn't very driveable on the street. I'm using TunerCat. Here is what I did:

I set the TPS% to enable Kickdown Mode and TPS% to disable Kickdown Mode both to 100%. This was meant to keep the transmission in Normal Mode all of the time, so it wouldn't jump from table to table as they rev it up. So far, it seems to have worked.

I set all of the Normal Mode shift points so it will shift into 2nd gear at around 3000RPM at any TPS%. I also set the Normal Mode shift points so it shifts into 3rd gear at around 3000RPM at any TPS%. It is set to never shift into 4th gear. The downshift speeds are set a few MPH below the speed to shift into that specific gear. This seems to be working as well.

I have the TCC set to lock when the engine is at 2500RPM in 3rd gear only. It is set to unlock when it drops down to about 2200RPM. This also seems to be working.

What I was trying to accomplish with this setup was for them to take it easy getting it into 3rd gear. They keep bringing it up until they feel the converter lock. Then, they can go wide open and the converter will stay locked until they are done and bring it back down. During my testing on the street, everything seemed to work except one thing.

When I feel the converter lock, it will unlock if I instantly floor it. If I take a second or two to get to WOT after I feel the converter lock, it will stay locked. I looked at my logs, and it showed between 6 and 14 RPM of slip when the converter was locked and I was at WOT. Is this normal or am I going to break something?

Is there a setting that unlocks the converter if the TPS rapidly increases? I only saw a setting for unlocking the converter if the TPS rapidly decreases.

Lastly, would I be better off using Normal Mode and Kickdown Mode together or is using Normal Mode only going to be okay?

Thanks for making it this far! LOL
I really appreciate it.

 

I'd leave everything alone and just change the table: "TCC WOT Forced Lock Speed Threshold Vs. Gear".
It'll lock at whatever MPH you set when flooring it.

 

Thanks!

I was thinking about that, but I would have to change my Kickdown Mode Shift Points and Kickdown Mode Shift RPM tables too. Even though I could set it to lock the converter at a given speed in a given gear, I would have to make sure it was in that given gear.

Now, would I have to change my Normal Mode tables to cooperate with my Kickdown Mode tables? If they don't, wouldn't it be possible that it would downshift when they floor it, and then try to lock the converter while the converter is under full load? I trust the converter clutch to hold if it is already locked, but I'm not so sure about it trying to lock at WOT.

I guess I'm just wondering if I have to change what I already did, because it seems to be working. I found a table called Line Pressure Modifier in WOT vs RPM but it is completely zeroed out. It won't be using that table because it will never enter Kickdown Mode, but the table doesn't have any effect in Kickdown Mode either because it is zeroed out. Are there any tables that modify the line pressure in Kickdown Mode besides the above mentioned table?

Is the 6-14 RPMs of slip okay, or is this going to cause a problem?

 

Are you trying to make it hold 3rd gear as long as possible?
Adjust the kickdown up/down shift points, and kickdown RPM threshholds (both must be met to shift) so it shifts into 3rd gear really early (and doesnt go into 4th if you want).

so 2->3 @ 3000rpm or whatever
and 2->3 @ 50mph

So if you stomp it above 31mph (kickdown mode 2->1 setting) it will stay in second and pull till 50mph then make a long 3rd gearpull to 126mph. Just tinker with it out on the street to get tit where you want it.

About the slip rpm, I don't know.

 

I think the way you did it (disable kickdown mode) is the best way. My everyday tune has kickdown disabled and I find it a lot more straightforward to work with.

I have thought a fair amount about how to tune the transmission for a dyno run, and I will set the 3->2 and the 3rd TCC lock very low, so you can start the dyno run from a low rpm in 3rd (maybe 1500). You ought to be able to do this in a way that will still let you drive it there - basically, the upshifts happen normally, so on the dyno you just bring it up until it shifts into 3rd, then let it coast down to 1500 rpm, then start the run. For 3->4 you just need to set the high TPS to shift at a very high mph, but the part throttle shifts can be normal.


I'll look through some of my logs and see if I have info for your other TCC questions.

 

Thanks for the replies everyone! Unfortunately, they changed the rules this year so a person had to be registered in the show to be able to run on the dyno. By the time I got there, registration was closed. Next year I'll have all the free dyno time I want, so I guess I'll just wait until then.

 

be careful sometimes locking a converter at WOT can damage it.

 

Thanks for the warning.

I think I bought a decent converter, but I was still unsure about having it lock at WOT. That's why I had it lock at a low RPM and at a low TPS value, so it was locking while it wasn't under much of a load. I think it has enough holding power once its locked, but I don't want to take the chance of it locking under a load.