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Old 08-07-2019, 12:20 AM   #14 (permalink)
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Originally Posted by EcoCivic View Post
Correct me if I am wrong, but my understanding is that the torque converter basically only multiplies torque from a stop or when trying to accelerate hard in a high gear.

I remember reading somewhere that a torque converter needs at least a 500 RPM difference between input and output speed (slip) to multiply torque, so any less than that just wastes energy from my understanding.
I believe without lockup and high engine power it almost always will have at least 500 rpm difference, and that will give about a 10% increase in horsepower and torque. Basically free power compared to a mechanical locked up clutch or locked torque converter. Free meaning there were no changes to the motor to make more power, but it comes at the cost of efficiency. Here is one chart I found from a real converter but looks like it might be something of a racing converter.
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