Thanks to Murry, it seems a whole new set of cool possibilities
has   arisen for warming up our Wankels.

   It's been a long time since I worked on diesel trucks, so I was'nt
  aware
   of Evans coolants. I just read through a couple long threads on
an RX   forum debating the issue. For more than a year now I have
read this   forum and have not heard of this stuff. If it's true the
pressure   remains low, or even zero, then we should be chasing this
one down in a   hurry. I have used water wetter for a long time in
my porsches and MX   bikes. According to what I have read so far, I
would have saved myself,   and a lot of other people, many headaches
by using Evans coolant   products.

   So what is it? Are the diesel guys wrong, and are the few RX
  enthusiasts
   similarly deluded, by promoting Evans products? Obviously, there
are a   lot of advantages in using a coolant that does not vaporize
within the   passages at or near zero psi; and what sort of pressure
will we see if   we use it in our pressurized systems? If it does'nt
vaporize, or   vaporizes very little, then we have a winner don't we?

   The stuff's not that expensive. Who wants to be the first to try?

   Search for Evans NPG+, on ebay.

   Anyone have a good set of specs on this stuff?

   Ed Carver

   I know people have used it but someone mentioned the heat transfer
   coefficient between coolant and metal is lower than ethylene glycol.
   Evans coolant is mostly propylene glycol.
   In order to properly test it one must have a "cylinder" head temp
   sensor.

   Paul Lamar

  We had many long discussions about it a few years back.  I have tried
  it.  I was using it when I lost all my coolant and landed on a
road in  2006.  You cannot run zero PSI.  All of mine squirted out
past a 7 PSI  cap and that is why I landed on the road.  It is used
in diesel engines  to raise the temp without boiling the coolant.
But we don't need or  want our temps as high as the boiling temp of
regular 50/50 coolant.  At  a given temperature, Evans will not
remove the heat as well as regular  coolant.

  No benefit to our application.

  --
  David Leonard

I guess that means the stuff expanded when it got hot and that was
the end of it. I was wondering about that while reading on the RX
forums as some of the guys ran it at zero psi and never had a leak.
Some of them used 13psi caps, I guess it just expanded and went into
the catch can to be drawn back when it cooled off. I'll sort out the
expansion issue.

It appears a radiator size increase is required in many applications,
cars or trucks.

Seems to me a big advantage to Evans would be the coolant would not boil
around the spark plugs.

Ed Carver



The Evans coolant does not raise the temp itself. It has a higher temp that
the coolant can get to before boiling. It does not allow "nucleate" boiling.
This takes place at hot spots. The bubbles rising from the bottom of a pot of
water is an example. On a diesel engine the liners move out and back on the
major and minor thrust sides as the cylinder fires and the piston is pushed
against the inside. When the outside is pushed out, it moves the coolant away.
Then as the liner returns to shape, the momentum of the coolant causes a
localized low pressure area that allows boiling. Then the bubbles collapse as
the localized area normalizes. As the bubbles collapse and the coolant crashes
back into the liner wall, a bit of the iron is eroded and pits form. Cummins
engines were very prone to this and eventually a leak into the cylinder
develops. Proper cooling maintenance helps prevent this problem. Old coolant
becomes acidic as the additive package is used up. You can measure a voltage
between the coolant and the metal parts when this happens. A litmus paper test
will then confirm.

Dale Davies