lock-up or Non lock-up

[jettle]

Can someone please explain the diff??? I am new to the whole torque converter thing and I am trying to figure it all out.

Thanks!

[jettle]

Also, How hard are they to install and are they noisy?

[RF Overlord]

jettle:

A lock-up torque converter is one that contains an extra "clutch", so to speak, that is commanded by the PCM to lock up and convert the T/C from a slip mode to a direct connection, like a manual transmission's clutch and pressure plate do. This improves fuel economy slightly, and reduces the heat generated by the normal slippage in all torque converters...when operational, it also eliminates the whole reason for HAVING an automatic transmission in the first place, which is to be able to start and stop the car without having to use a clutch (and to multiply the torque for better acceleration), so it has to be able to "unlock" at lower speeds, and at a stop, or the motor would stall...

A lock-up T/C can only be installed on a transmission that is designed for one, so either you have one or you don't; you can't easily "convert"...

Most cars since the 80's have had lock-up T/C's from the factory.

[darebren]

In other words, who feels the extra few hundred for a locking PI Stallion 3000 stall converter is needed?

[jettle]

Yes is it worth it??? Are our factory converters lock up? What is lost if that is not opted for?

RF thanks for the explanation

[cyclone03]

Well I have a locking one,in a few weeks I'll have it installed and will report back....

But....
Once the car reaches 3rd gear more than likely it doesn't need the converter to slip.
Your rolling along at speed so engine torque will move the car fine.

Now from a stop tell engine is above the stall speed of the converter it's unlocked and,well,converting.
WOT1000rpm -3000 slipage then shifts at 5800 or so and rpm drops to 3800 conveter is still unlocked then rpm rises again to around 5000 and the 1/4mile has passed.
During WOT I THINK the converter will be unlocked but I don't know if the car will feel "snappier".

I believe the fact that the convert (PI Stallion) is about 15lbs lighter than the stocker will give the engine a lighter feel,same as underdrives I'm guessing.This should make it feel livelier.

In the MM unless you planned on having a race only car I'd say go with a locking converter everytime.Unless your power was way above 550hp then you would need a beefed tranny and custom converter anyway.

[SergntMac]

I won't disagree with the advice already posted here, Bob and Lance have it nailed. May I add my own experience?

I have owned an MM with a single plate Stallion, and my present MM has the triple plate. The single plate ran about 750., the triple plate was 1200. or so. Are they worth it? Are they noisy?

Yup, and yup. My tranny has been modified for performance, and my TC is set up to lock up under normal driving conditions. This abates the slip and improves MPG across the board. It gives me more direct control over speed, and allows for "engine brake" before brakes are necessary, so, I'm saving a bit there too. Under WOT, the TC does not lock and it does it's thing as Lance has explained so well. You will see lower ETs and smoother launches from this investment, I guarantee it.

The lock up can be noisy, down right nasty if you're stuck in slow moving traffic and the tranny shifts without the power behind it. I've had to explain this to new passengers, but after they sample what the car can do with the right amount of free space in front of it, they seem to understand.

About the only thing I could comment on here, is the weight savings. Having pulled two OEMs and installed two Stallions, it's my guess that the weight difference between the Stalion and the OEM is closer to 30-35 pounds, but that includes tranny fluid still nside. Nonetheless, it's a considerable difference, which is less parasitic drag. Add that to improved torque multiplication, and the Stallion is a winner. Sure, other TCs are less expensive, but Precision Industries provide a two year warranty and "free" adjustment if you pay the shipping. You get what you pay for, Stallion or not...IMHO.

[jettle]

Thanks guys!

SergntMac,
Can I please ask you one more question? What differences did you experience between the single and triple plates? Is one esier to live with? I commute with my car three days a week so it has to be something that can be put up with in traffic.

Jeff

[RF Overlord]

darebren:

I was unaware that the Stallion unit was even available as a non-lockup unit for the 4R70W...I'm not sure you would want one as the transmission and PCM would be trying to tell it to lock up when it wasn't able to...that might create some weird situations...

jettle:

Yes, the Marauder's T/C is a lock-up unit...are you sure you're not confusing a "lock-up" T/C with a "high-stall" T/C?

[jettle]

RF,

I juust noticed that there was a single-plate and multi-plate. I thought the site stated that the muti-plate was a lock-up.

Is that wrong?

[TripleTransAm]

I was under the impression that multi/single simply referred to the description of the lockup clutch itself...

I suppose the higher number of plates in the torque converter's lockup mechanism simply serves to increase the total friction surface, ie. more friction surface to dissipate the energy in slowing down either side to match the other. If one thinks of it in terms of a manual transmission clutch, if you'd have a single plate, when you drop the clutch you would have a single surface contact that would rub until the two sides are matched in speed enough to grip solidly. I suppose a multi-plate setup would provide several such matching surfaces to grip, increasing the overall friction surfaces.

[TooManyFords]

Originally posted by SergntMac
My tranny has been modified for performance, and my TC is set up to lock up under normal driving conditions. This abates the slip and improves MPG across the board. It gives me more direct control over speed, and allows for "engine brake" before brakes are necessary, so, I'm saving a bit there too. Under WOT, the TC does not lock and it does it's thing as Lance has explained so well. You will see lower ETs and smoother launches from this investment, I guarantee it.

Ok, so if I wanted to duplicate the trans programming you have, what do I ask for specifically? Where are the upshift / downshift speeds set and at what rpm is the TC programmed to unlock when slowing to a stop?

Second, does this scenario only work if you have a Stallion or will it also work with the factory TC? (I'm guessing the latter since the TC is really not programmable and the tranny is doing all the work via two input shafts, no?)

Since having my car reprogrammed by Dennis in Ennis and then installing the 4:30 gears, I've noticed that my car has absolutely no engine braking at all. In fact, it will hold 35 mph on it's own if I let it. Tach sits at about 1600 and the car just keeps on cruising. Anyway, I want to address this and feel that a simple reprogram of the tranny and TC lockup will fix all the ills.

Comments?

John.

PS: Great pics from the Chi-town meet. Still wish I could have been there!

[MM03MOK]

Originally posted by TooManyFords
PS: Great pics from the Chi-town meet. Still wish I could have been there! You were missed!

[SergntMac]

Originally posted by TooManyFords
Ok, so if I wanted to duplicate the trans programming you have, what do I ask for specifically? Where are the upshift / downshift speeds set and at what rpm is the TC programmed to unlock when slowing to a stop?

So many questions...

On my first MM, Jerry provided the lock-up in ECM tuning, because back then, Jerry was the only tuner who could access the back half of the ECM. He set it to lock-up after the 2-3 shift, and it worked great. It would lock-up in 3rd, or OD, leaving the feel of a five speed behind. As I used engine brake to slow down, the tranny would down shift, but stay locked. If I wnted to unlock the TC, a brief tap on the brake set it free.

The same proceedure did not work well on the triple plate, that third clutch pack floating around was a PITA. Once Jerry rebuilt my tranny and modified the valve body to tak more control over shifting, he didn't have to mess with the ECM anymore, and shut a lot of stuff off. Now, the triple plate behaves like the single plate, but it is sensitive to power in the upshift. If you pull up when it wants to shift, it will show it's disappointment.


Originally posted by TooManyFords
Second, does this scenario only work if you have a Stallion or will it also work with the factory TC?

To be honest John, I can't say. I didn't experiment with the OEM T/C, and prefer not to guess. I will add that the single plate is best for the N/A MM and the Triple plate is necessary for S/C MMs. Zack disagrees, and that's fine, but we both are waiting to see how long his single plate will live once the '04 season opens.


Originally posted by TooManyFords
Since having my car reprogrammed by Dennis in Ennis and then installing the 4:30 gears, I've noticed that my car has absolutely no engine braking at all. In fact, it will hold 35 mph on it's own if I let it. Tach sits at about 1600 and the car just keeps on cruising. Anyway, I want to address this and feel that a simple reprogram of the tranny and TC lockup will fix all the ills.

Yup...Worked for me. I agree, John. There has been a lot learned about the MM tranny since Ennis, I am sure Dennis can do something for you today.

[jettle]

Wow you guys are great! Thanks for all the info!

[TooManyFords]

Dennis,

Per the conversation between Mac and myself, what will it take to duplicate what Mac has for my car?

I don't have the Stallion yet nor will I get it until I've had a chance to run what I got at the local strip next spring. However, I'd like to experiment with these types of changes now when the roads are clear.

Because you did the "straight to the box" type of mod, how much to convert to a chip scenario? Ideally I would like to have something I can put on my laptop and hook into my car to experiment with, even if it only works just on my car and cannot be used on anyone elses. (I'm just that kind of go-go-gadget guy!)

And Mac, thanks for the 411 on how yours is setup. As we get more and more of us modding our cars, the input is invaluable!

Cheers!

John

[Heavy351]

ooohhhh I am VERY interested in this as Sarges' setup really sounds like a big plus over the stock schizophrenic shifting.