Quote:
Originally Posted by gchemist
Is labor included with the $1800 for install? If so, I think it's fair because intalling on a 4X4 is harder.
Stall is when the converter engages engine and transmission together. It's the same thing a lock-up does. In a stall, it's a mechanical engagment. It happens regardless of speed because it's based on engine RPM and load. My converter locks at ~45 RPM either in 3rd or OD. It locks at higher RPM if I put more throttle on it. Stall is good for perfomance motors. Stall is set to "lock" when an engine begins or is in its torque power curve. In most cams, power starts a ~1200-1500 RPMs and up. Racing cams curves are in a much higher RPM range.
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Stall speed and lockup are not at all the same thing.
Stall speed is the maximum rpm the drive turbine can spin before the driven turbine starts to spin which is the point where maximum torque multiplication occurs. It varries widely depending on the how much engine power there is and when it comes. The same converter behind two different motors will achieve different stall speeds. The RPM rating is very general. Generally speaking an appropriately modified engine will be able to make an 1800 RPM converter 'stall' at around 1800 RPM.
Lockup occurs when the coupling clutch inside a lockup converter is applied creating a direct link between the input turbine and the output. This allows the converter to achieve 100% efficiency when fully applied, which reduces heat and stress in low RPM high speed situations like cruising on the highway and also provides meager fuel efficiency gains. At low RPM tourque multiplied by the converter goes un applied which generates tremendous heat. By locking the converter no multiplication occurs, so no excess heat is generated. A 700R4 that is regularly used in overdrive should always have a lockup converter that working correctly.