Ken Powell wrote:

Paul,
   The stock oil cooler is 19.625 * 4.5 * 2 for an area of
176.625 sq. inches.  It appears that this cools fine up to 185
HP (Tracy), but the duct needs to be correct.  Note that some
parts of the country have 100 degree days in the summer and
Arkansas is one of those so I am anticipating cooling problems
just like everyone else.

   If the oil provides 1/3 of the cooling in a rotary, and we
are saying that you need 500 to 1000 sq in for water cooling, it
is no wonder that we are having lots of oil cooling problems due
to the small size of the stock cooler.  Why does the stock oil
cooler seem work so well despite it's small size????  It is
built very rugged, but does not seem special from a cooling
perspective.  Most importantly, do you believe that the stock
oil cooler will be enough to handle from 200 to 240 HP?  I'm
worried about not being able to cool our PP engine.  I realize
that Fred Morino's work shows us that the larger the radiator
the lower the drag, all other variables being equal.

Ken Powell

It has these trick turbulators inside the oil tubes I think.
I am prepared to go with something else if it does not work.
IMHO I have yet to see a perfect oil cooler duct however.

Paul Lamar

Hans Conser wrote:

Don't forget that the 3rd generation RX-7 R1 model had *TWO* oil coolers, even
though it had the same power output as the others (255 HP), these models all had 3
inline catalytic converters, BTW, which provided quite a bit of back pressure
reducing power.

Hans Conser

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