A friend of mine is getting a 2400 stall torque converter made. He says the builder asked him if he wanted a "lockup". Don't all t/c's "lock up" at their stall speed?

 

Sometimes the term "lockup" is used to refer to a "closely coupled" condition seen at higher speeds where the impeller and stator are nearly at the same speed. But there is always slippage unless you have a "lockup" converter. That is a converter with a clutch pack setup to literally lock (couple) the impeller and the stator together so that they rotate as a unit, i.e. there is no slip and therefore near 100% efficiency.

All modern OEM automatics use lockup converters. This improves fuel economy, decreases heat buildup in the tranny, lowers engine wear by decreasing rpm at cruising speed, etc. The lockup is controlled via the PCM in the 4L60E in a 4th gen. Lockup converters are not used on very hi-po drag setups because the clutch packs aren't strong enough to stand up to high hp levels. Precision Industries is making a lockup converter that they say is suitable for drag racing http://www.converter.com/vigilante.htm but as to how much hp it can actually handle, I don't know. It would be a nice thing for a drag car to be able to lockup at the top of third gear, this would improve trap speeds as well as give a little boost to the ET.

What year/transmission is your buddy getting the converter for?

Rich Krause

 

Thanks for the response Rich. He is running a 700r4 in his 3rd Gen . Maybe 350hp and a final drive of around 3.42.

 

You're welcome! Sounds like he could use a lockup converter.

Rich Krause