Jim the Cooling Guy's ears perked up on this one...
On Date: Sat, 15 Jun 2002 20:38:23 -0500, "Eric Linnhoff"
<knuckledragger@kcweb.net> typed thusly:
>Howdy all, was at Advance Auto (used to be Western Auto) this afternoon
>picking up some plugs and brake fluid and saw a display with gallon
>containers of this ProBlend brand radiator cooler stuff. It's supposed to
>make your coolant run "up to 28 degrees cooler".
Uh-oh. Huge, largely unsubstantiated claims rarely stand up...
>The only reference to ingredients I could find on the container was
>"contains petroleum distillates". The instructions said to pour the whole
>gallon in ($15) and add another gallon of distilled water to end up with
>what they called a "summer blend of 80% water and 20% ethylene glycol".
Petroleum distallates? Well, ethylene glycol is a petroleum distallate, or
parts of it started out as such, whatever.
>Is this basically just a surfactant like Redline's Water Wetter or is it
>something totally different?
I'm not at all sure what it is -- the Pro-Blend website
(http://www.pro-blend.com) isn't terribly informative as to what their "40
Below" coolant additive really is. I'm guessing you ran across a "premix"
version of 40 Below that comes mixed in with ethylene glycol coolant
(possibly dilute) -- the website instructions are for the "blend it
yourself" version.
>Is there any truth to their 80/20% "summer blend" claim? Should I not be
>running a 50/50 mix of water and coolant in the summer months? Next weekend
>I'm due to fly around Blackhawk Farms for a day and would like to have my
>cooling system working at peak efficiency. The coolant that's in there now
>is just over a year old with about 24K miles on it.
For starters, these guys are from Texas and spend a couple weeks each
summer getting their brainpans fried on the Bonneville salt. Yes, you can
run an 20EG/80W "summer blend" coolant. Whether it's really 20/80 depends
on whether your cooling system volume is the same as their assumption that
"Most vehicle cooling systems hold 3-1/2 to 4 gallons of liquid". If yours
holds more (or less), the proportions are going to be off. For that
matter, if their proportions are based on a 3.5 gallon system, if it's a 4
gallon system, the proportions will be off.
Interesting cautions -- don't use 100% water, don't use "synthetic" (huh?
EG is EG regardless of whether it's made from dino juice or designer
molecules. Maybe they're referring to the newer OAT and HOAT coolant
additive packages -- GM's DexCool is OAT and the G-05 used by a lot of
European cars, a few Fords, and an ever-increasing number of DCX products
is HOAT) or "environmental" (they mean the Sierra propylene glycol stuff.
Ask me off-list about what THAT stuff is a bad idea and why their
advertising claims got them whacked by the FTC a couple years back)
coolants. Don't use any sealers or Stop Leak or other additives.
They *claim* that "antifreeze absorbs heat and holds it". Well, okay, it
does, in the hot engine when it's colder than its surroundings... but IT'S
SUPPOSED TO DO THAT! You see, when it then gets to the radiator (and/or
heater core), when the coolant is hotter than its surroundings, it GIVES UP
THAT HEAT. That's why we say your engine is "liquid cooled". It uses a
flowing liquid as a heat transfer medium. Even plain water acts this way
when used in a similar fashion. The air the VW and Porsche air-cooled guys
blow over their engines performs the same purpose -- absorb heat from
engine, hold on to it while flowing elsewhere, then release said heat to
atmosphere.
Okay, let's talk real quick about heat capacity. Plain water has a
specific heat that's mighty tough to beat amongst
readily-useable-in-a-cooling-system liquids. In fact, it's the reference
other substances' heat capacities are compared to to generate a "specific
heat" number. Water's specific heat is 1. One. Unity. Other substances
with heat capacities less than that of plain water have a specific heat
less than one. It's a percentage, a ratio, a fraction, however you want to
call it. Think of it as a PAX index for heat absorbtion/release rates for
various substances, with plain water as A Modified.
All that said, EG has a specific heat that is less than one. So, yeah,
plain water (with Water Wetter or some sort of corrosion-prevention
additive package added) will work somewhat better -- and many sanctioning
bodies require it in racing or even open-track use because EG spills are
slicker than oil spills and harder to clean up. But for most of the world,
a 50/50 mix is a Good Thing. Every car I've had some sort of part of in
the last 12 years has had its cooling system sized with a 50/50 EG/W mix in
mind. We'll test with other mixes (typically ranging from 60/40 to 40/60
EG/W) to make sure it's "tolerant" of other coolant blends, etc.
The only way I can think of for this bundle of petroleum products calling
itself 40 Below to work is if they're fairly light fractions and thus
*evaporate* in the engine, condensing again in the radiator or even just
while still in the coolant jacket on their way out of the engine. Heat of
vaporization is a Very Big Deal Indeed and if you can pull off a working,
stable 2-phase (in this case, liquid and vapor) cooling system, Heat of
Vaporization is your friend. Any time you do a phase change (from solid to
liquid, or liquid to vapor), the medium can absorb a tremendous amount of
heat energy *without changing temperature*. If you've got an engine
running in a steady-state environment (stationary power such as a
generator, aircraft, marine, or, and this is relevant given the hobbies of
the Pro-Blend principal, a 5-mile-long WFO run on the salt flats of
Bonneville), you have a much better chance of being able to get a 2-phase
cooling system to work. For most of the rest of us, the transient nature
of the speed/load curve in our street and race cars makes it considerably
harder to pull off in a stable fashion.
For my money, I'd seriously consider running plain water with a basic
additive package (anti-corrosion, anti-foam, some surfactants) for track
use and run good ol' 50/50 on the street. I can't say I'd spend the bux on
Pro-Blend's "40 Below" without a whole lot more information than the
Pro-Blend folks have forthcoming. I'm going to see what I can do to get
some more info, will report back to the list once I find out.
Jim Crider
autojim@att.net
/// unsubscribe/change address requests to majordomo@autox.team.net or try
/// http://www.team.net/mailman/listinfo
/// Partial archives at http://www.team.net/archive
|