94lt1m6

iTrader: (9)

Like the title says what is the difference between a locked/unlocked converter, from a technical and practical view. Also I see they give different dyno numbers, usually locked is higher. Do they also give different track times. And last of all how is it performed. I just dont know anything about them. Thanks guys.

performabuilt

iTrader: (25)

Ok I see M6 in your name so , Basically a converter is a fluid coupling device, Two rotors (fan like assemblies) Running very close each other transfer the engine energy through fuid to the transmission. When one rotor is mechanically turned by the engine the fluid moves and causes the other rotor (Turbines) To spin. This is how and auto can stay in gear but not actually move at lower RPM now the lockup clutch is another part of the converter, Its a small clutch that works similar to you clutch in your M6 but hydraulically applied and effectivly bypasses this fluid coupling to eliminate loss under certain conditions, (When locked the auto transfers power like a manual trans.)

Now on the HP loss on the dyno while its true autos are not dyno queens. its a small trade off for what the converter can do the manual and clutch can never do , The converter through this fluid coupling and the difference in the turbines can multiply torque, This is the reason auto all things being equal with a good stall will take a manual most every time , A good stall converter in a certain RPM range can multiply the engines torq by as much as 2 times. 200 FT LBS becomes 400 FT lbs etc. And torque is really what wins races. It get things moving and the more you have the faster you will get from point A to point B. With a manual trans you only have the engine torque to work with 200 FT LBS is just that,

As for locked or unlocked which is faster, Generally unlocked With and auto, DYNO numbers mean very little and are only usefull for tuning. Locked you loose that torq multiplier thats giving you the advantage to start with.

I hope this helps some I have a bit of a cold and doing cold medicine some others may be able to clarify it better. But thats my explaination well tonight anyway. I may read it tomorrow and redo it.

Circle-D

iTrader: (21)

Good info Performabuilt, I would like to go a little deeper in the lock up clutch. Just like all standards, some torque converters have a clutch as well, one being the 4L60E. The clutch is inside the torque converter and can not be seen from the outside. In a standard the clutch is activated by the clutch pedal, in an automatic it is controlled by fluid from the transmission. The clutch is only commanded to come on at certain times by the computer. Just as Performabuilt said, during the non lock up phase, the input shaft of the transmission is being turned completely by fluid power. While this method has definite advantages with torque multiplication, it does loose some power, typically 5% to 10%. This loss in efficiency is why the dyno numbers are lower when the converter clutch is not applied.

Now for the hard part, one would think that by applying the clutch in the converter, called locking up the converter, at the track would net better times. But this is not usually the case. Since the converter actually multiplies torque, locking the converter will slow the car down. If the car has a big power adder like Turbos, then locking the converter sometimes can help out times, every setup is different.

Hope this helps, any more questions just ask.

Chris

94lt1m6

iTrader: (9)

Alright i get the picture better now...Thanks alot you guys.

Can all coverters be locked, or unlocked. I herd some guys talk about doing it with a programer, or with a switch they wired into the pcm?

tj1986c

iTrader: (1)

Great information. I wanted to know the difference between being unlocked/locked as well. I was just scared it was going to be a dumb question, lol.

conde'strans

iTrader: (8)

Same here!

sixvi6-camaro

iTrader: (9)

If its a Lockup TC it will have the ability to lock. Some drag cars choose to have converter with no lockup as they never drive on the street. On f-cars the Torque Converter Lockup is controlled by the PCM and can be changed with tuning or forced on/off during tuning if need be. There is a way to make a manual switch to force lockup but I'd not recomend it. Locking at too low an RPM is not very good and if you forget to unlock it when you come to a stop would probably be hard on the clutch as well.

performabuilt

iTrader: (25)

Thanks I was hoping someone would clarify more. I am a trans guy proficient in converters but not good at explaining them.
Frank at PerformaBuilt

Gilbert@Ace Racing

Good info here.

I thought I would add something as well.... take a look at the photos below. The clutch itself is bonded to the piston. Hydraulic fluid from the tranny pushes against the piston which moves it towards the front cover... or engine side of the converter. At that point the transmission input shaft spins at the same rpm's as the eninge when the converter is Locked-Up.

The dark ring around the Piston in this photo is the single clutch that carries the weight of the car when the TCC is Locked-Up. There are multi disc versions that are very similar in design to multi disc Manual clutches.

Here is a close up view of the Stock Clutch material.

This is the opposite side of the Piston. Notice how it has Dampening Springs very similar to the Damepning Springs on Manual Clutches.

This photo shows you the inside of the Front Cover I mentioned earlier. The flat surface is where the TCC clutch itself interacts with the body of the converter.


It is not wise at all to make dyno pulls or WOT passes on single disc converters when they are Locked up! We pull at least one failed converter a week that has been subjected to this sort of abuse.

Hope that helps... for more picks of the internals of a High Stall Torque Converter and a bit more of a discussion check out this thread...

https://ls1tech.com/forums/automatic-transmission/844118-about-ace-racing-transmissions-converters.html

There are also some pics of a High End Bolt Together Converter that will show you just how similar but at the same time different a 350 - 800 H/P Stall Converter would be as compared to a 2,500 H/P Converter.

Good question there Mr. O.P.! I haven't seen that one in a very, very long time if ever.

g

Matt D

iTrader: (49)

haha

94lt1m6

iTrader: (9)

I know this is a crappy explanation but here we go... I have a TCI Super street fighter 3500. Before the tranny rebuild: I would be driving, and at about 45 mph almost every time the car kind 'bogged' for a sec, dropped a couple hundred rpm than felt like it locked up and smoothed out. After it did this I didnt have the stall with my converter any more when i pushed more gas, it just acted like a manual would locked in gear. Now since i rebuild the tranny it doesnt do that anymore. So was that the lockup effect i felt? Any ideas why it doesnt do this anymore?

performabuilt

iTrader: (25)

Well thats does sound like lockup , When you say dosent do it anymore do you mean it remains loose and you dont have lockup?

Gaunt

iTrader: (11)

+1 on waiting for good responses

94lt1m6

iTrader: (9)

Correct. It remains loose.

bjamick

iTrader: (31)

Well the converter should be locking up at around 55 or 60mph really depending on where your foot is. Its supposed to lock, so if its stalling down the interstate i bet that thing is nice and toasty warm inside your tranny .. Which isn't a good thing. I hope you have a trans cooler to say the least.

94lt1m6

iTrader: (9)

Yes i do have a trans cooler thank god. What could cause this, how can it be fixed?

bjamick

iTrader: (31)

Whats the best way to fix it? Take your car to a reputable tuner and have them tune on your transmission. SO that away the converter will act how it is supposed to. Thats the only way to fix this problem, bc the computer is the one to tell the converter to lock up.

94lt1m6

iTrader: (9)

how about a manual switch that will cost me 5 dollars opposed to a 200 dollar tune.

bjamick

iTrader: (31)

Then whats going to tell the converter to unlock?? You can do the switch but you will prob end up burning up the lock up clutch after awhile of doing that.

performabuilt

iTrader: (25)

You could do that but there the issue mentioned above with the unlocking and in addition when you ground the solenoid to cause lockup the PCM will likley not understand and set a code for the lockup solenoid being shorted and set limp mode, To do it that way you would still have to see a tuner to have the test for that code removed.

But the fact is you need to 1 determine of lockup is even being comanded, You can do this with a scanner or tuner or if you dont have these contact me and ill give you and easy test to determine if i fact this is occuring , If it is then you will know you are dealing with either and electrical or mechanical transmission/converter component , If its not then you will have to have someone look at the tuning or attempt to diagnois it with a scanner,