ZF in and going again!
Posted: Sun Feb 19, 2006 6:21 pm
ZF in and going...This time rebuilt, with a low stall converter to aid in cooling and performance.
I ran the truck up a long hill, about 110KPH all the way up, stayed in 4th lock up all the way, and auto trans temp 76DEG. I haven't tried it off road or slogging through peak hour traffic yet, but the temp so far looks encouraging. The result of the low stall converter, about 200 to 300 rpm lower, is that the off line acceleration is the same as a V8, AND must be contributing to the cooler running temps also. The engine braking issue in 1st low seems to be fantastic so far, but the only prob I have is the vehicle wants to drive off through the brakes idling in low drive/ first gear... torque monster that it is.
I will try to get some dyno figures one day, It feels monstrously torquey at 2000 rpm and lower, and with the boost wound up to 15psi was obviously enough to break the last 'box.
All in all It is going well, but I want to bring the lock up engagement speed down from 90 to about 80. Because I'm using bigger tyre diameters, I need to trick the gearbox into thinking the car is going faster than it is, so the governer weight will need increasing I guess, but how much I don't know just yet. My cousin suggested writing a mathematical thesis on calculating the required change in governor weight to compensate for the change in output shaft speed versus actual road speed, (which would be a very important formula to have actually.) It could be useful to people contemplating major gearing changes using pre electronic autos, so they can retain a decent shift point etc, especially going from a higher revving engine to a slow revving diesel for example. Might take him up on this IF I EVER GET TIME!!!
Will keep all up to date as things progress.
JC
I ran the truck up a long hill, about 110KPH all the way up, stayed in 4th lock up all the way, and auto trans temp 76DEG. I haven't tried it off road or slogging through peak hour traffic yet, but the temp so far looks encouraging. The result of the low stall converter, about 200 to 300 rpm lower, is that the off line acceleration is the same as a V8, AND must be contributing to the cooler running temps also. The engine braking issue in 1st low seems to be fantastic so far, but the only prob I have is the vehicle wants to drive off through the brakes idling in low drive/ first gear... torque monster that it is.
I will try to get some dyno figures one day, It feels monstrously torquey at 2000 rpm and lower, and with the boost wound up to 15psi was obviously enough to break the last 'box.
All in all It is going well, but I want to bring the lock up engagement speed down from 90 to about 80. Because I'm using bigger tyre diameters, I need to trick the gearbox into thinking the car is going faster than it is, so the governer weight will need increasing I guess, but how much I don't know just yet. My cousin suggested writing a mathematical thesis on calculating the required change in governor weight to compensate for the change in output shaft speed versus actual road speed, (which would be a very important formula to have actually.) It could be useful to people contemplating major gearing changes using pre electronic autos, so they can retain a decent shift point etc, especially going from a higher revving engine to a slow revving diesel for example. Might take him up on this IF I EVER GET TIME!!!
Will keep all up to date as things progress.
JC
