[DeTomaso] Anyone with Experience with Evans NPG Propylene glycol Coolant
GW
gow2 at rc-tech.net
Mon Feb 14 12:32:48 EST 2011
Agreed. With a thermostat controlled cooling system cooling observations
don't mean anything unless your cooling system can not keep up. That is
where I was. Going back to regular coolant my cooling system was far
more able to keep up. While I did not measure input and exit temps the
difference quantifiable. Also, changes I made were individual one at a
time changes so I could evaluate each change individually.
I would be concerned about a 260 degree exit temp for normal cars.
Especially knowing areas of the engine are above that temp. The babbot
on melts around 350 and I don't think they would be happy at 300.
If it is say a drag racer whose engines are tore down every run, every
couple runs, may be a different story.
Suffice to say if the cooling system can't keep up it won't keep up with
Evans.
G
Ken Green wrote:
> Gary,
>
> If you measure the exit temperature of the coolant it seems like
> it will always be higher with Evans coolant because about a 60% higher
> delta temp between entering and leaving the engine is required to
> remove the same amount of heat. I think the meaning of engine temp
> needs to be defined better.
>
> Some of the people posting to forums seem to think 260 deg exit
> temp for this stuff is fine. That seams really hot, but they were
> fine with it. They seem to think that the temp is not as important as
> if the coolant is boiling. There was at least one guy who collected
> ping data and said the Evans collant made a measurable difference and
> allowed running a more aggressive advance curve.
>
> It appears that Rotax specifies Evans coolant for their aircraft
> engines:
>
> http://www.rotaxservice.com/rotax_tips/rotax_feed4.htm
>
> (near the bottom)
>
> Ken
>
>
> --- On *Mon, 2/14/11, GW /<gow2 at rc-tech.net>/* wrote:
>
>
> From: GW <gow2 at rc-tech.net>
> Subject: Re: [DeTomaso] Anyone with Experience with Evans NPG
> Propylene glycol Coolant
> To: JDeRyke at aol.com
> Cc: detomaso at realbig.com
> Date: Monday, February 14, 2011, 4:40 AM
>
> I have played with Evans coolant and know some others who have as
> well.
> There are some advantages and disadvantages.
>
> Advantages
> 1. There is no and can be no water in the system. The boiling
> point of
> the fluid is increased dramatically. This is advantages if you
> have an
> engine with hot spots. It is good to run an engine in the 190-210
> degree
> range. Metallurgy likes it and it keeps moisture out of the oil
> during
> operation. However with a water temp of 200, areas in the
> cylinders are
> hotter. A hot spot can develop which boils the water and creates a
> vapor
> pocket. Once the vapor pocket emerges, the hot spot gets hotter
> and the
> vapor pocket gets hotter. This leads to detonation and other.
>
> http://www.rc-tech.net/cars2/hs.jpg
>
> With Evans and the higher boiling point, there is no hot spot.
>
> 2. Running Evans coolant, the system is an unpressurized system. I
> know
> some one running a radical engine and this has stopped head gasket
> failures.
>
> Disadvantage
> 1. It simply does not cool as well as water and traditional
> coolant. If
> you have a more then adequate cooling system, it is no big deal.
> If your
> cooling system is borderline it will begin to raise temps when it
> can't
> keep up.
>
> I tried it for a while in my MG. I was having some cooling issues
> with a
> new crate engine and not enough baffling. My thermostat was not
> keeping
> up. When I changed from Evans back to traditional coolant I saw a
> significant drop. My engine was almost able to keep up; at least a 10
> degree drop over all for the same situations and temps. After
> putting in
> an oil cooler I have never had a cooling issue since under any
> situation.
>
> 2. If you have problems on the road there is only one fluid you
> can use
> as a substitute (I forget which one). You can't use most of the
> coolants
> on the market; if you do you wreck the fluid. This can be very
> inconvenient.
>
> 3. It's very expensive. If you do ANY cooling system work on the
> car you
> will need to find
> a way to reclaim the fluid. It is too expensive to drain off.
>
> 4. Here is the worst thing; its flammable! I read about a race
> some time
> ago where the driver was severely burned; not by gas but by burning
> coolant!
>
> That's what I learned from it.
>
> Gary
>
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