Quote:
Originally Posted by Tapani
Update:
Drove the SVX first time after the q-panel and tranny cooler cooler work....
The distance required for the TCC to lock is now half of what is used to be.... 9 km instead of 17-18km, so the original cooling setup was too much under these conditions anyway.
I monitored the fluid temp with a lap top. The Marshall temp gauge is still being shipped from California... The temp never got above 171F in the pan. The conditions were the easiest possible, though. Mostly just cruising and 32F ambient. The car was garaged at room temp (as always), so I did not start at freezing point  .
The opening temp for the bypass is 180F so I guess the flow never reached the cooler this morning.
/T |
Interesting to see how it performs without any sort of device in the cooling circuit. I would be curious to see if the transmission would be able to maintain temp at speed with TC locked. When I had the old cooler without a fan mounted in front of the radiator, it would overcool the fluid and the TC would actually unlock on the freeway. At that time I was driving on a relatively flat road where the car would cruise in 4th lockup for 100 miles. It was even more annoying than usual then as it would lock and unlock every few minutes. I even had it come out of 4th one time when it was close to 0f outside with a headwind.
Let us know if you can perform a similar experiment. I do not know if they have stretches of road like that where you are or if you drive the car on them. I would theorize that the radiator adds a small amount of heat to the ATF (enough to keep it above 100) as I don't see the heat generated by the pump and friction, transferred to the metal pieces of the transmission from the engine, etc. to be able to keep the fluid warm enough.
In a nutshell, I am curious to know under which circumstances the heat transferred to the ATF by the coolant in the radiator (call it x) is of a value greater than the capacity of the heat exchanger portion that will cool it back down (Y).
Seems to me that the system would be designed to have the following properties:
Rough assumptions for ATFT (Z), assuming AMB temp is 0-100f, ECT 195-212f
System as designed:
X+Y=Z+ such that Z<100
X+Y=Z such that 150<Z<178
X+Y=Z- such that Z>178
Obviously such calculations cannot even be attempted without a set ambient temperature at the least, but since ATF dexron II/III is not much sensitive to temperature in the -50 to 280 ish it doesn't matter much.
This would beg the question as to why even heat the ATF at all, which is asked frequently. My main response to that question is that the fluid is designed to operate in the range of 150-200 and that is not crucial but in a transmission such as the 4EAT it is important to have "all hands on deck" as far as helping that high clutch stay lubricated, sticky, and applied.