Differential cooler sizing question

D

disquek

Well-known member
This is a GTL question.

I installed a diff cooler and the temps dropped some, but not enough.

I have all the data (it might be a bit much for a post) from the temp sensor both before and after I installed the cooler (different tracks).

The question is, is there a good way to figure out how to increase the temperature drop? I'm assuming things like more air or a bigger cooler are the answers, I'm trying to figure out how much.

-Kyle
 
Are you sure that the temps are too high? Full syn oil can take very high temps. 300 will cook seals a little soon but shouldnt bother the hard parts, assuming enough gear size VS torque.
 
Hi Mike,

I'm sure of the temps. I'm measuring them using a proven setup (Autometer sensors into my DAQ) and I've backed that up with TherMax strips. Before I installed the cooler it was seeing almost 300 on a 75 degree day. That's too high.

It's not the seals that I'm most worried about. This is a quick change and it's got an aluminum case. The aluminum starts getting soft when it gets hot. Also, I'm sure the bearings and gears aren't loving the sauna either. The fluid comes out looking great, so I'm within the limits of the fluid. It's everything else that I'm trying to save.

With the cooler it's still seeing 240. That's better, but still not ideal (I'm told ideal is 200). I'm curious if a bigger cooler will make much difference. I'm currently using an Earls cooler thats core is about 6"x6". I could get a bigger one, but I'm not sure if that's the answer or not. I was wondering if there was some math that could use the temperature data graphs to predict the BTUs and figure out the ideal cooler size.

-Kyle
 
The math has to involve the mass of the hard parts , the BTU value of the oil, etc. way too much. IMHo to get a fair estimate.( plus air densisty!) Just copy known good valuesIMHO.
The QC often run up near 280. much more and they leak more. They always leak. It should run cooler if you are using most of the tubes as oil tank. For road racing, we try to keep the oil out of the ends with the double/ triple seals. Put these extra seals out near the ends letting the oil slosh back and forth. Run a fan blowing up into the rear deck area. They cant work without a fan.
have driven most of these rears, for 12 gal runs and have not needed the cooler fan turned on. I am not the fastest anymore, but I have the pedal down most of the time. It is amazing how much hotter the fast guy can get the gearsets. :)
The oil level may be above the fill hole for some housings. Check with the manufacturer, Iknow we had some issues running with ovaltrack rears in the old TA cars.
I would be real happy with 240. I have never seen 200 or less. We heat the drive line to 200 or more to qualify the Busch cars.
GTL has how much power? The QC gives away a lot of power because of all the extra whirly gigs. Less spinning parts= more applied power. maybe 4-6hp loss @ 300.
 
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