A stupid torque convertor question
Thread Starter
Le Mans Master
Joined: Jan 2006
Posts: 6,564
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From: Woodstock Georgia
A stupid torque convertor question
Fitst off I have a 95 with the 4L60E trans. Along with some other changes I am going with a 2400 stall convertor. Now my tech buddy says that is a bad idea. He is thinking at cruising 70mph in OD the revs will be low enough that the convertor will never lock up, which in turn will cause added heat and possibly damaging heat in the trans.
What are the chances of that??
Thanks
What are the chances of that??
Thanks
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 207
From: Orlando FL
I believe that at 46 mph the signal is sent from the PCM to the lock up relay. Its based on mph and not engine speed for lock up. Even with the new converter, I would think it would work the same.
Not totally sure about this but there is some logic to it. Just seems like the rpm it goes from 4th gear to lock up would be higher.
Not totally sure about this but there is some logic to it. Just seems like the rpm it goes from 4th gear to lock up would be higher.
Last edited by pcolt94; Jun 16, 2011 at 09:56 AM.
Safety Car
Joined: Jun 2006
Posts: 3,629
Likes: 28
From: FL
Your adviser is confusing stall speed with lock up. Stall speed is determined by the relationship between the angle of the blades on the impeller (driven by the engine at crankshaft speed) and the blades on the turbine (splined to the transmission input shaft). The converter multiplies torque until the speed of the turbine nearly matches that of the impeller, that point is sometimes referred to as coupling speed or lock up. The term lock up when so used is entirely different from the lock up clutch.
The lock up clutch was developed to improve fuel economy, it eliminates the small amount of slippage that occurs in even the best designed torque converter. The lock up clutch is applied by hydraulic pressure only when the car reaches a predetermined speed as programmed in the PCM, stall speed is not a factor.
I am running a 9 1/2" converter with 2800 rpm stall, the lock up clutch functions just like the stock converter.
High stall converters typically do generate more heat than the stock converter, but it has nothing to do with the lock up clutch and can easily be handled by adding a cooler.
The lock up clutch was developed to improve fuel economy, it eliminates the small amount of slippage that occurs in even the best designed torque converter. The lock up clutch is applied by hydraulic pressure only when the car reaches a predetermined speed as programmed in the PCM, stall speed is not a factor.
I am running a 9 1/2" converter with 2800 rpm stall, the lock up clutch functions just like the stock converter.
High stall converters typically do generate more heat than the stock converter, but it has nothing to do with the lock up clutch and can easily be handled by adding a cooler.
Race Director
Joined: Apr 2003
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From: moraga ca
Safety Car
Joined: Jun 2006
Posts: 3,629
Likes: 28
From: FL
