Steve40th396

What mph should I set in TUNERCAT for converter to lock and unlock at?. 396LT1 2800Rpm Vigilante and 3.73 gears in Corvette. 4L60/700R4.
Right now its set at lock at 52 and unlock at 42. Not sure if those speeds are right. I do have abit of sbudder in the 45 mph area at cruise. Tune is good.

FirstYrLS1Z

for reference,my 98Z locks at 40mph and unlocks at 35mph.

Steve40th396

Thanks. I went out and datalogged. I realize when I am at low cruising speeds with torque converter locked, it surges. I need to keep the converter unlocked till I get above 50 mph. Is that safe? I have 2800 rpm vigilante, 3.75 gears and two coolers for transmission...

FirstYrLS1Z

in your 1st post you said 'shudder',your next post 'surges'.
when I'm in 4th(overdrive) gear and convertor locked at low speed(37-39mph),the 'surging' I get is engine surging because rpm(1100-1200) is too low. just like driving a manual 6 speed in 6th at low mph.
shudder would be convertor,surging would be engine. rpm too low in the powerband to be efficient.

Steve40th396

Well, the fsm calls it chuggle.. Regardless, it is during converter lock up and the car surges/shudders in gear. Its annoying when at speeds its locked.
I am going to raise the mph for the converter to lock. sound good? Will it hurt going to 55mph vice 45mph?

FirstYrLS1Z

no reason it should hurt. would be a good question to ask vigilante.