[DeTomaso] To thermostat or not to thermostat

[Will Kooiman]

Jim,

Yes, I've heard the argument about slowing the water down so it can absorb
more heat.  I don't agree, though.

That's like telling someone to eat more if they want to lose weight.  If
they eat more, it'll pass through their system faster, so it'll have less
time to be absorbed.  Right?

Think about how a thermostat works.

If the engine starts getting cooler, the thermostat starts to close.  Less
water flows and the engine gets hotter.

If the engine starts getting hotter, the thermostat starts to open.  More
water flows and the engine gets cooler.

That's very simple to me.  More water flow = cooler.  Less water flow =
hotter.

Don - Maybe it's the turbulent vs. non-turbulent flow.  It doesn't matter to
me.  The important thing is that more flow = more cooling - otherwise
thermostats wouldn't work.

Hey - that could be a new diet.

Patient: Why am I overweight?
Dr.    : You're eating too slowly.
Patient: What?
Dr.    : It gives the food too much time to be absorbed.
Patient: What should I do?
Dr.    : We need to put golf dimples on your intestines in order to create
turbulent flow so the food does not separate from laminar to non-laminar at
the boundary layer.
Patient:  Say what?
Dr.    :  I said, you need to start working out.
Patient:  Oh, okay.

Will.

-----Original Message-----
From: detomaso-bounces at realbig.com [mailto:detomaso-bounces at realbig.com] On
Behalf Of Don Thomas
Sent: Wednesday, May 21, 2008 12:00 AM
To: Jim Gray
Cc: Will Kooiman; DeTomaso List
Subject: Re: [DeTomaso] To thermostat or not to thermostat

Here is the engineering explanation that I got from my friend (the
engineer's engineer and rocket scientist) at Boeing who deals with
thermodynamics everyday.

"Turbulent heat transfer (flux) coefficient (Nusselt number
http://en.wikipedia.org/wiki/Nusselt_number ) is linearly proportional to
the Reynolds number.  The Reynolds number itself is linearly proportional to
velocity.  Don't feel bad - this wasn't covered in your basic engineering
thermo class.  It's in the realm of convective heat transfer. "

Which what he is basically saying... you want high rate of flow in order to
induce turbulence to transfer heat more efficiently.

This is also mentioned on the Stewart components website at the bottom of
one of their tech tips page. i.e.:

"Metal temperatures always increase when you slow the water pump down."

http://www.stewartcomponents.com/tech_tips/Tech_Tips_6.htm

So if someone tells you slower is better... that isn't true for cooling.

I hope that helps.

-dt





> Thanks, Will.
>
> I think the idea is that if the water flows through the system too quickly
> it can't absorb the heat properly.
>
> My Robert Shaw thermostat didn't perform any better than the lesser priced
> NAPA 197.  Just my experience.
>
> Jim Gray
>
> -----Original Message-----
> From: detomaso-bounces at realbig.com [mailto:detomaso-bounces at realbig.com]On
> Behalf Of Will Kooiman
> Sent: Tuesday, May 20, 2008 9:57 PM
> To: detomaso at realbig.com
> Subject: Re: [DeTomaso] To thermostat or not to thermostat
>
> I agree with Mikey about running the Robert Shaw 333-180 thermostat.
There
> aren't any downsides to running a thermostat - unless you get a cheapo
> thermostat - which the Robert Shaw is not.
>
> I don't buy the idea that you have to slow down the water or it won't cool
> enough.  It makes more sense to me that if you don't restrict the water,
> it'll cool too much.  So, in other words, if you're not running a
> thermostat, and the engine is running too cool, put a smaller restrictor
in
> place.  This only makes sense in a controlled environment - like dirt
track
> racing.
>
> This is one of those topics that, in my opinion, we over analyze.  Use a
> proper thermostat so it'll stay hot enough.  Get rid of the air in the
> system.  Make sure the fans are working properly.  That's all it takes.
Oh
> yeah, stainless pipes/tanks and green stripe hoses, but that's more for
> corrosion/leak protection - not cooling.
>
> By the way, I haven't had a high pressure/swirl tank in over 4 years.  I
> haven't put many miles on my car the last year (mostly due to traveling
for
> work), but before that I drove it 1,000 miles a month.  The only time it
> overheated was when the fans stopped working - and that was in 100+ degree
> weather in stop/go traffic, up hill, with no shoes on.
>
> Will.
>
>
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