Birty Dastards Jeep Club
Tech Forum => Workshop => Topic started by: ferretjuggler on June 03, 2014, 03:32:42 AM
-
How do I work out the stall speed if I was in the market for a new torque converter?
Obviously look up the spec in a factory workshop manual. :098:
Except that my 360 apparently has had the cam changed, plus a four barrel 600CFM carb and manifold fitted.
Higher stall speed?
Any easy formula for working it out :017:
-
On the Buggy I have a 2200 not sure if that helps??
-
I would have thought that is relevant to type of engine as well. Doesnt the torque convertor have it marked (auto). Normal idle range can be from 800rpm upwards
-
Can't see any markings on it.
Will give it a good clean up and look again.
-
An RV torque converter will give the beans from tickover if that's any help......
I guess you need to know the details of the cam to know when it wakes up and to when it's at full chat.
-
To put it as simply as possible:
Stock ZJ converters are 1800 rpm stall speed for 4.0 and 5.2, 5.9 converter is 2300 stall.
Stall RPM is the maximum RPM the converter input can turn with the output at 0 rpm. This is also the point where it will deliver max torque multiplication. Under lighter loads (less throttle), the RPM won't climb as high on takeoff, so it's not like it'll climb to 2500 and then go or anything. It doesn't, however, lock at the stall RPM (although it feels like it). Under WOT (especially at lower vehicle speeds) there's a good bit of slippage / multiplication going on.
The lockup clutch is controlled by the computer and is applied to completely lock the converter input and output together when driving at a high enough speed. This reduces heat production greatly. It has nothing at all to do with RPM, other than the minimum RPM for the computer to command lockup (which is about 1100-1200 in 4th on a stock 5.9). It's possible to add a switch to manually engage the lockup clutch on the RH box.
So if you were to hold the breaks on and rev the motor in drive, as the wheels start to want to turn thats the stall speed, look at the rev counter. Thats the point where its like dumping the clutch on a manual. Obviously on the road with normal driving you dont get the mechanical resistance as you would with the brakes on so it will move but will slip. As the appropriate speed point is reached it really starts to hussle as the convertor isnt slipping anymore ( its locked up). If it were locked up all the time whenever you came to a halt the car would stall like a manual stopped in gear.
With a bigger cam you need to get "on cam" as soon as possible so one would get a higher stall convertor, change the gearing or both depending on application.
-
Well I just learnt a lot, nice post
Sent from my iPhone using Tapatalk