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o.k i know i should know this but i never really read up on it or researched it. but can someone please explain torque converter lock-up and why most performance converters are non lock-up? thanks

Pretty much it is just about the same difference between a spool & limited slip.

A lock up converter does not slip, generates less heat, puts most power to the ground. Uses a solid coupling(lock-up clutch) to connect the turbine to the pump.

A non lock up, can slip, generates an enormous amount of heat, puts less power to the ground. They require the use of good external coolers, good fluid, ect..

There are a few more pros & cons, which I am sure will be brought up, but I just woke up & am still on my first cup of coffee, so I am suprised I typed out that much

o.k. understood. so why then on a high performance application would they offer a non-lockup as opposed to the lock up? also a "tight" vs. a "loose" converter? what are these terms referring to?

most cars on a 1/4 mile pass will wipe out the whimpy 1/2" band overpowering the ability to stay locked up .(street car lower speed/rpm) pumping shyte threw your trans!!!! you want the converter to be "loose " enough to get your car into pk. torque before you leave but slip as little as possible . if your car is light enough and/or powerful enough you can over power /drive trough the converter and loose alot of et. if it is to tight you have to slug your way up too pk tq. before it really starts moving good . thus why you dont by crappy converters or lie about your combo and use to a "good" converter company .some ultra high $$$ converters have a multi disk lock up but its heavy ,one off and adds another circuit and seals to fail .

The original idea behind "lock-up" torque converters was fuel economy. The vehicle manufacturers discovered that a standard non-lock-up torque converter was inefficient at highway speeds. The converter is only a fluid coupling between the engine and transmission and naturally has some "slip" to it. The manufacturers put a clutch in the torque converter to eliminate this slipping, reduce engine RPM, transmission fluid temperature, and give better highway fuel enonomy. With the clutch engaged, there is now a solid lock from the engine to the transmission.

While there have been lots of advances in technology and materials, the idea of a racing lockup torque converter is a kinda lost cause. The benifit from this technology would be awesome, but the cost involved would be beyond the average race team.

I eliminate lockup in performance transmissions due to the fact that it will NOT hold up to abuse. I install lockup elimination kits instead and have the converter built "clutchless". That along with a good auxiliary cooler will make the transmission more dependable.

Just my .02 cents, Tony