REFLECTOR:Re: NPG+

Wed, 21 Apr 2004 12:48:32 -0500

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I'm doing my first annual and don't have time to get into details on
NPG+, but I didn't want to be silent and imply I concur with your
comments.  The temp gauge on my '96 chevy p/u typically runs at 180 F
which is where auto thermostats have controlled it for years.  I realize
that there are periods during engine operation where the pressure will
reach the cap limit and coolant will run to the reservoir, but I believe
that for most of the time there will be little pressure on the system.
However it matters little if there is pressure or not.  The bottom line
is that a non-boiling coolant will greatly increase the engine temp, by
several 10s if not a few 100s F.
Racing engines are not a good comparison, because engine longevity is
not as important as power and fuel economy, so you can bet that
longevity will be compromised.
Automakers have been under pressure for many years now to increase gas
mileage and I can't imagine any design engineer that doesn't understand
that higher engine temp = higher efficiency.  So why haven't they
increased the engine temps?  My guess is that longevity/reliability
suffers too much.  Whatever the reason, auto engines were designed for a
specific temp and to significantly increase that temp is an experient
that is best done on the ground.

John

Alex Balic wrote:

>  You should check that John, Most systems run with several pounds of
> pressure- past that, the cap will open and allow the excess coolant to
> run to the reservoir (boil over condition) the cap will also open when
> the system is warming to allow the expanding coolant to leave. If you
> want to run hot for better power then you need a higher pressure cap
> to prevent boiling. Typically engines will run at 220-230 which is
> above the 212 that water boils - adding glycol does not suppress this
> point. Have you ever seen someone make the mistake of removing the cap
> on a warmed up engine- you only make that mistake one time- the water
> boils instantly when the pressure is removed and departs the radiator
> like a shaken can of beer.  Racing engine systems will typically run a
> few pounds higher than passenger cars to allow a higher operating
> temp- going to 100% non aqueous coolant will also allow this since
> these liquids are designed to boil at at higher temperature and do not
> require the higher pressures inside of the system which is usually
> limited by the strength of the radiator and seals at the water
> pump.Alex

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I'm doing my first annual and don't have time to get into details on NPG+,
but I didn't want to be silent and imply I concur with your comments.&nbsp;
The temp gauge on my '96 chevy p/u typically runs at 180 F which is where
auto thermostats have controlled it for years.&nbsp; I realize that there
are periods during engine operation where the pressure will reach the cap
limit and coolant will run to the reservoir, but I believe that for most
of the time there will be little pressure on the system.&nbsp; However
it matters little if there is pressure or not.&nbsp; The bottom line is
that a non-boiling coolant will greatly increase the engine temp, by several
10s if not a few 100s F.
 Racing engines are not a good comparison, because engine longevity
is not as important as power and fuel economy, so you can bet that longevity
will be compromised.
 Automakers have been under pressure for many years now to increase
gas mileage and I can't imagine any design engineer that doesn't understand
that higher engine temp = higher efficiency.&nbsp; So why haven't they
increased the engine temps?&nbsp; My guess is that longevity/reliability
suffers too much.&nbsp; Whatever the reason, auto engines were designed
for a specific temp and to significantly increase that temp is an experient
that is best done on the ground.
John
Alex Balic wrote:
<blockquote TYPE=CITE>&nbsp;You should check
that John,&nbsp;Most systems run
with several pounds of pressure- past that, the cap will open and allow
the excess coolant to run to the reservoir (boil over condition) the cap
will also open when the system is warming to allow the expanding coolant
to leave. If you want to run hot for better power then you need a higher
pressure cap to prevent boiling. Typically engines will run at 220-230
which is above the 212 that water boils - adding glycol does not suppress
this point. Have you ever seen someone make the mistake of removing the
cap on a warmed up engine- you only make that mistake one time- the water
boils instantly when the pressure is removed and departs the radiator like
a shaken can of beer.&nbsp; Racing engine systems will typically run a
few pounds higher than passenger cars to allow a higher operating temp-
going to 100% non aqueous coolant will also allow this since these liquids
are designed to boil at at higher temperature and do not require the higher
pressures inside of the system which is usually limited by the strength
of the radiator and seals at the water pump.Alex</blockquote>

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