I got some updates to my car over the weekend and i'm struggling with LS1edit to find the proper tables and values that need changed. I added a Yank PT4000 converter and a 3.42 10 bolt rear end but I need some help in changing some of my trans shift settings. Under light throttle at about 30mph it seems like the car wants to shift from 1st or 2nd directly into OD. It will go from about 3000 rpm all the way to about 1000 rpm. (These values can be off as I was using the stock tach and we know how accurate they are!) NO changes have been made to the trans tables before this change other than adding the 3.42 gears. I'm not sure if it's a TCC lock issue or a part throttle issue where it's trying to shift too much. Any advice would be much helpful!!

There also seems to be a binding or surging feeling while crusing. Kind of feels like the car is rocking back and forth under low speeds. Could this be the TCC locking and unlocking or just a quirk of the higher stall speed of the converter?

 

First the bucking is caused from locking up the converter too earlly. If you ever have ridden in a stick at too low of a rpm you will get some bucking also. To correct this you can change your lock up table in the trans section to only lock in fourth gear at 50mph. I would not lock it up at like 85% tps and up if it is not a multidisc converter that is designed for that type of use. You can set those values at 85-100% tps to 249 or whatever that stock value is leave it there. Set the unlock at 45mph on the forth gear section. Set the rest of the 2nd and 3rd gear lock and unlock columns to 249 or whatever that stock high value was for the 85-100% range was. That should cure your bucking problems and give a little better drive ability.

Now for the shifting. First thing you need to do is change your gear ratio in the gear tab to the new 3.42. I believe that will rescale some shift points. If not what I do is up or lower the values till I get it shifting were I like it. For wot the car will shift when it reaches either your max rpm set for that gear or the 100%tps vs mph setting. It only needs one of those conditions met to shift. The shift tables you can adjust in the normal and hot shift mode. The performance tab is not used in the fbody or vette. PM me if you need some more insight. I could send you an edit file for you to use as an example if you need.

 

An edit file would be nice, even if just to compare tables! You can email it to me at gillbot@daytonfbody.org

First thing I did was change the gear ratio so that's set but the MPH values didn't scale like I thought they should. I did the math on a gear calculator page and it looked as though the values for my 2.73 gears stayed behind after I changed the gear ratio. I took a 3.23 gear file I had and and copied over some table values in hopes that it would get me closer. I haven't uploaded it yet though because of all this rain.

I definately need to tweak the lockup points though. I figured that was the bucking feeling. I just wanted to be sure and get a 2nd opinion!

 

ttt, any other tips?

 

James, email me your updated ls1edit file with just the 3.23 gear change, I'll fix the rest for ya.

ls1_ls2tuning@yahoo.com