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View Full Version : Torque Converter Lock-up.


Rockettman
10-13-2010, 05:07 AM
I thought I knew what this was, but what is meant by:
"Torque Converter Lock-up"? How does it apply?
Darrin
10-13-2010, 05:44 AM
Torque converter lockup is where the converter has a lockup clutch and that clutch is applied to give an actual mechanical 1:1 connection between the engine and transmission. That applies to these cars. There are different methods to get that mechanical 1:1 connection though.

There is a decent description with pictures at the link below.

http://p71interceptor.com/tranny/converter/

Darrin
thathotrodlincn
10-13-2010, 05:48 AM
This a simplistic explanation. The TC is a torque multiplier/fluid coupling. It relies on slip. That is it is hard bolted to the crankshaft (via the flex plate). The output speed of the TC is lower than the input, crankshaft speed under normal conditions. A "lockup" TC has an internal mechanical clutch that (under certain conditions) fill freeze the two halves of the TC ensuring that the output of the TC is at crankshaft speed, This reduces transmission heat and improves (?) fuel economy. Hope this answers your question. PM me if you need more information.
Rockettman
10-13-2010, 05:53 AM
Those two answers above DO explain my question very well.
Is there a way to "know" when it's locked while driving or is it something that goes unnoticed?
Zack
10-13-2010, 06:34 AM
Those two answers above DO explain my question very well.
Is there a way to "know" when it's locked while driving or is it something that goes unnoticed?

Its the 4th shift.
Rockettman
10-13-2010, 06:48 AM
Do I have this right?

So if someone says that they have a "3500 rpm stall converter" (or whatever rpm they chose to buy) - does that mean that in 4th gear only, it is running (locked) 1:1 with the engine; and not until then?
FordNut
10-13-2010, 07:01 AM
Its the 4th shift.

or 5th gear? 1-2-3-4(od)-lock
FordNut
10-13-2010, 07:03 AM
Do I have this right?

So if someone says that they have a "3500 rpm stall converter" (or whatever rpm they chose to buy) - does that mean that in 4th gear only, it is running (locked) 1:1 with the engine; and not until then?

Depends on the tune. Some tuners lock the converter in 3rd & 4th, some in 4th only, I believe the stock tune even locks it in 2nd.
MrBluGruv
10-13-2010, 07:13 AM
Is there a way to "know" when it's locked while driving or is it something that goes unnoticed?

Well one way I'm able to tell, at any given speed let off the gas some and apply it again, if the engine revs span a few hundred RPM while you do this then it isn't locked, but if they stay put and the engine just essentially gets louder, it's locked.

Lidio's tune is probably the most simple about it, somewhere between 60 and 65 mph in 4th, as long as you aren't really in the throttle, it WILL lock the TC, and no other gears will. Some other tunes I've had will lock in like 2nd I think and then 3rd it did. Kinda a funny experience driving at 30 mph with the TC locked and the engine turning 1100RPM in this car. :P
Rockettman
10-13-2010, 07:33 AM
What's the advantage / disadvantage to locking in different gears (2nd / 3rd)? Don't you want it to lock?
Zack
10-13-2010, 07:35 AM
or 5th gear? 1-2-3-4(od)-lock

Its the 4th shift because you dont shift from 0 to 1. Well I guess you could count that one. :P
FordNut
10-13-2010, 07:37 AM
What's the advantage / disadvantage to locking in different gears (2nd / 3rd)? Don't you want it to lock?

economy vs performance
FordNut
10-13-2010, 07:41 AM
Its the 4th shift because you dont shift from 0 to 1. Well I guess you could count that one. :P
Yeah, I got your meaning after I posted.
When I take off I count the gears/shifts,
stop-go, 1-2, 2-3, 3-4, lockup (if it's warm).
If the engine is cold it doesn't lockup.
Blackened300a
10-13-2010, 07:49 AM
Mine slips in like a 5th gear. Ill get the O/D shift and then the lockup will just smoothly come in and the rpms will drop. On the dyno it bogged me down when it locked up under WOT. Its setup to be unlocked during city driving and unlock with light pedal pressure.
Rockettman
10-13-2010, 08:00 AM
I always thought that extra drop on rpm's after the 4th shift, was my OD turning on. I didn't know it was the torque converter locking.
Blackened300a
10-13-2010, 08:08 AM
I always thought that extra drop on rpm's after the 4th shift, was my OD turning on. I didn't know it was the torque converter locking.

Yep, thats the convertor lockup. Then you can ease the pedal down to unlock it and give you some pulling power in 4th.
Rockettman
10-13-2010, 08:31 AM
Power = unlocked?
Economy = locked?
Blackened300a
10-13-2010, 09:04 AM
Power = unlocked?
Economy = locked?

Basically...