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I have mentioned several times in discussions regarding
the EVANS coolant
that to really gain benefits from its use that the coolant
flow would have to be increased to ensure the removal of adequate heat from the
engine. The fact that the EVANS has a 300F+ boiling point may delay "boil
over" but it does little to protect our rotary's because they are cooked long
before that point is reached. In fact, the 250F boil over of the 50/50
mixture pretty much ensures that if you reach those temps you have probably
cooked your engine. However, preventing Boil-over (as Al Wick has
mentioned) is a worthwhile consideration.
But, all that aside, my point was that give the lower
specific heat and the fact that the rotary engine is more constrained
temperature wise- means that to flow the same amount of heat out of
your engine per unit time with Evans - you MUST increase the coolant flow
rate. IF you do increase the flow rate with Evans to the point that the
coolant temperatures are within the limits for the rotary then you stand a much
better chance of benefiting from using EVANS.
I happen to notice in reading material on the EVANS
coolant, that the above point is also made by them: This is a direct quote
from material on their web site.
"THE EVANS SYSTEM
Since the Evans coolant possesses different flow and thermal
characteristics than normal EGW, some changes are in order.
First, there is no need to use a pressurized cooling system, but an overflow
bottle is necessary due to the expansion rate of the coolant. Evans markets 0-
and 4-lb. caps for most radiators. The low-pressure cap is used to keep coolant
loss in check on late-model engines. To totally
optimize this system, a high-flow
Evans water pump, thermostat and radiator should be installed.
Working with data from the field, most late-model
performance cars, unless approaching the 650-hp level, can reap
substantial performance gains with just the installation of the
Evans coolant and high-flow
thermostat. Realizing the huge potential for power generation
through the use of this coolant, Evans has designed many ancillary components to
maximize the potential for late-model fuel-injected
engines. Pulleys to increase stock
water pump speeds, water pump application for TPl, 5.0s and
Buick GNs along with radiators. "
Note the reference to late-model performance cars is a
reference to the fact that these newer engines are designed for and
operate at higher coolant temperatures (more fuel efficiency) than
previous engines (or our rotary engines).
The point is as EVANS points out - there are some definite
benefits to EVANs. However to gain the maximum benefit and given our
rotary's lower temperature limits, I personally believe these changes
are essential if you want a system that keeps you engine within safe
limits.
The changes Evan's mentions include high flow pumps,
pulleys for faster flow, high flow thermostat and high flow radiators.
This implies (to me at least) that if you are going to use Evans then you need
to design your coolant system for its use from the git-go.
My trouble-making 0.02 {:>)
Ed
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