blaster

Does anyone know anything about the Torque Converter lock schedule for Automatics and how it's configured using the SCT XCal?

Recently I backed down from a 93 Torque tune to a 87 Performance. My 93 tune did not have the Converter lock schedule tweaks but the 87 Performance did. To my surprise the 87 seems to pull harder than the 93 and I wonder if it's because of the converter tweak.

But I have a problem in that auto downshifting is not good now. It seemed before, without the tweak, I could be in Drive with OD off cruising about 45 to 50. If I give it substantial gas (not enough to downshift to the next lower gear) I would hear the engine start to bog then it would kick in a little and I'd feel I slight surge in power and hear the rpms go up.
I wonder if this is the torque converter locking. It almost feels and sounds like it downshifted but I know it does not for sure.

With the converter tweak in the tune it does not do this. It continues to bog and if you press harder on the gas it eventually just downshifts to the next lower gear...sometimes going into 2nd gear which can be unexpected.

So with my new tune the Converter tweak feels great at WOT and upshifting but is lousy when auto downshifting. Does anyone else have tunes with this converter tweak and do you find the same thing? Is there a way to adjust the converter tweak so you get the strong pull in upshifting yet downshifting still works like stock?

blaster

No one knows how the schedule works? Schedule based on RPM, MPH, fluid pressure? Earth's magnetic field?

Zig-Zag

I just took a look at the Converter Lock Schedules of one of my tunes in Extreme Tune. The graph that is displayed has MPH and Throttle Position on it's axes.

blaster

Thanks for looking. I don't have the XTR file to open so that's why I couldn't look at it.

So it's MPH and throttle position...hmm. I might ask and see what the chances are of getting the XTR file so I can open it and make adjustments there.

Cowtown

I think I have noticed the same thing. My 93 tune seems to be "softer" with the tranny shifting, similar to my 87 tune. The 91 tune though is a monster. I just put some 94 gas in and the 93 tune the other day and haven't had a chance to drive but I'm going to be testing it some more this week and maybe trying bringing the tune down to a 91 again and see if it feels different. I can't imagine why they wouldn't map the same tranny settings unless you told them to not bother.

blaster

The tunes are from Doug and I've been running the 89 and 93 torque tunes for awhile now. I accidentally blew off my 87 Perfomance tune on the XCal. Doug being the great support guy that he is gave me my 87 Performance tune back in a LL3 file. At the same time I asked if he had any tweaks I could try and he said yes and sent me the 87 Perfomance tune I refer to that has the converter lock tweaks. So that's why my other tunes don't have it. I'm not sure if Doug is doing the converter tweak by default now. If I can get the downshift issue resolved but still maintain the upshifting characteristics then this will be may favorite tune and maybe I can get my 89 and 93 set the same way with the converter settings.

06GT4RAD

If you ever so lightly tap the brake pedal while accelerating this should trigger the TQ lock also.

Richard

blaster

Thanks for the tip. I will try that when it does the bogging issue I first described. If it locks in I'll know for sure that's what's going on....the TQ converter is not locking down at that particular speed and throttle position.