[T3] T-4

Jim Adney jadney at vwtype3.org
Sat Dec 10 06:42:28 PST 2011

On 9 Dec 2011 at 23:17, Keith Park wrote:

> I can say that at 12K feet and stock T3 injection the car would be gutless
> but cool oil temps at low RPM even if lugged but if you upshifted for more
> HP and higher RPM the Oil temps would ROCKET upwards....

I assume you meant "downshifted."

Let me offer an alternate explanation to your observation: In the 
high gear and low rpm the oil flow to the hot areas of the engine was 
low, so not much heat got carried away. Those areas got hot, but you 
didn't see it on your gauge because the low flow down the pushrod 
tubes had plenty of the time to shed heat thru the pushrod tube 
walls, and the oil in the pan had lots of time to shed it's heat thru 
the case wall.

Once you downshifted and the RPMs went up, you got lots more oil 
pumped and splashed into areas that were quite hot. That oil carried 
lots more heat down the pushrod tubes, but shed only about the same 
amount of heat in that trip, arriving in the case much hotter. Then 
with the pump running faster, the oil had less "dwell" time in the 
case to cool off, so what you saw was higher oil temps.

I suspect that the hotter oil temps at low RPM actually meant that 
your critical engine parts were now getting better cooling.

It's really easy to forget that there's often more than one way to 
interpret data, and "there's the rub."

Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA

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