Quote:
Originally Posted by wiedemab
Interesting! I remember the discussion about this system in one of the Z28 videos, but I guess I didn't really think through it.
So you are using the engine coolant to cool the trans fluid - typical
You are using the trans fluid to cool the differential - interesting
Are normal manual trans temps that much cooler than a differential or does this only work because the trans fluid is being "pre-cooled" before being sent back to the diff cooler?
I'll bet that adds a lot of capacity to the trans fluid system!
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The system now holds 4.5 quarts of trans fluid I'll need to chech the diff volume but it should be a little more also.
I'll need to look up the kW heat rejection from the trans but it is a lot less than the diff. Off memory the diff needs 3 kW of cooling and the trans needs 1 kW and the oil cooler in the rad rejects 5 kW so the fluid is over cooled at the rad then sent to the diff. The trans fluid leaving the heat exchanger in the diff is still cool enough to cool the trans. We did it this way in production due to the cost of pumps and coolers. The pump in the Tremec trans is relatively cheap compared to a electric pump. We can run a ZL-1 and a Z/28 on track for tank fulls of fuel with no over temp issues. Before we added this cooling loop a ZL-1 would over temp the diff in 5 laps. I think the C-6 Vetts have a similar system.
Since I added diff coolers to my project my ring and pinion life has gone way up. . It also allows only one set of -6 lines to the front of the car. On Red Devil I had -6 AN for the trans and -8 AN for the diff due to the length of the lines and the viscosity of the fluid when it was cold. This system is also lighter that two big Weldon electric pumps. Red Devil still has the original ring and pinion in it from when I built the car and it is quite.
Another side benefit to this set up is it can also pre-warm your diff and trans in the pits. On cold mornings at the track if you let the car idle in natural the trans pump is working moving fluid to the red where it is heated then to the diff and the trans warming them. Nice for 35 degree mornings like at OUSCI.
At 740 HP to the tires diff and trans cooling become real issues.
My trans cooler in my rad is around 10 kw, bigger that the Z/28's, due to my higher output.
Cool oil is happy oil.