Shift Time 0 vs 6.38?

[deva123]

I'm running a 1995 LT1 and 4l60E off a 8051 ECM. I started with Steveo's Free Online Tune and calibrated the Speedo. It starts and runs great. No more idle stall, but shift points were way off. I used the Bluecat tool and applied new data to the TCC lock and unlock tables, up and down shift points, WOT RPM, Shift, TCC tables. Test drove shift were smooth and on time. Decided to adjust shift times. All research points to lowering shift times. Some even recommended to zero out tables for firmer, faster shifts. Some of the factory bins I compared contradict this. While some have 0's on the 3-4 column and the performance tables. Other bins such as Vettes and f-bodies have these columns and charts maxed out at 6.38. Which I would think would cause slower sloppier shifts. (See attached). I'm a bit confused. Hopefully someone can offer some guidance as to if I should bottom out or max out shift times and why. Thanks in advance. 19630

[steveo]

i know very little about 4l60e tuning but a delayed shift at heavy throttle would allow a higher shift point, wouldn't it? seems like one of those things where you can either zero it out and set strict shift points, or set your shift points a bit early and let the delay add some dynamics to let it rev a little bit higher depending on TPS.

[deva123]

Happy New Year! Thanks for taking the time to respond. I read your reply last night after getting home from a NYE party and couldn't not comprehend. Reread it today with a clearer head and that makes total sense thanks for the explanation.

[tayto]

do some research on the LS guys that use HPTuners, i think they like to set the shift time from 0 to 0.3. Don't quote me on those numbers. I know for 4L60E short shift times will lead to longer life, there should be accompanying internal transmods as well but that is beyond the scope of this post. Not sure if the LT1 PCM has torque management or not, but if it does KEEP IT.

having a high number like 6.38 tells me that area is disabled or not used, but i am just guessing. It more likely means "no timer" or same as 0

[ralmo94]

As far as I understand a shorter shift is less slip while shifting, the settings are for the adaptive target to change the shifting pressure, it can only shift so fast, and some tutorials I have read on it say to set it to 0 and log shifting time, then set it to the fastest time you logged. I have also been told 3-4 isn't adaptive.
For what it's worth tow haul settings are all 0's.

[Kitch]

I've just had the 4L60e rebuilt in my G20 van, it's now running a Blueprint 383 with a multipoint RamJet 350 intake on it.
I'm also interested in reducing shift times as well, my shift times are still currently set to stock at the moment.
I've been trying to find some info about safe recommended settings before I change anything.

I've set it to shift from 1-2 at 5000 RPM, in the data log and I can see the shift solenoid activate close to 5000 RPM @ W.O.T but the actual shift doesn't go through until 5500 RPM.
I'm hoping reducing the shift times to appropriate levels will help reduce the RPM difference between commanded shift RPM and actual shift RPM and increase the life of the trans.

[In-Tech]

Hiya's
The "adaptives" basically don't work in these early computers. I wouldn't set anything under .25 in those fields either way. Adjust everything in the pressure tablles and/or in the force motor current table. I do both when I can.

[Kitch]

Thanks for the reply, I appreciate that you "basically don't work in these early computers" but would you have any more specific info to offer around your recommendations for changes to make in the pressure tables?

[tayto]

you should really be doing internal mods if you want to increase pressure ie: pressure relief&boost valve. you can crank up the pressure in the tune but it's only going to go as high as what the relief and pump are setup to do.

[Kitch]

I believe the transmission builder has done that, he said the trans should now be able to handle 450HP.
I was just wanting to compliment the 4L60e's internal mods with some appropriate changes in the tune.

[tayto]

i normally just change shift points in the tune. if i want a softer or firmer shift i play with orifice sizes in the separator plate. usually tuners get into trouble when they start messing with pressure tables

[sherlock9c1]

I'm hoping to play with the 8051 torque management tables found in EEXTRA here sometime soon.

But, before you tune a 4L60E that's got over 40K since a rebuild on it, as a part-time 4L60E builder, I would absolutely drop the pan and put in a new boost valve (TransGo or Sonnax 4L60E-LB-01 (or 02 depending on year), and a TransGo drop-in pressure regulator valve (https://transgo.com/product-details/4l60e-pressure-regulator-valve/).

I do enough of these that I purchased the Sonnax vacuum test equipment, and the pressure regulator valves are shockingly leaky on every pump I've tested lately. That will cause poor line rise, or worse, line pressure oscillation that manifests as intermittently soft shifts. Or, put a pressure gauge on the trans, and watch the needle swing back and forth under load.

I had one unit that went down from 200 all the way to 100 and back during WOT in first gear. A good 4L60E should stay high and touch 220-230psi sometime during WOT first gear. If it happened to shift while the needle was low, the shift would be soft. Having that inconsistency would drive a tuner crazy.

Once the mechanicals are addressed, tune to your heart's content.