DeTomaso Mailing List: July 2001, Message #70

I agree, every manufacturer would add a baffle to the radiator design
rather than installing a larger radiator for the "heavy duty cooling system"
option.  I will also add that my mercedes uses the AC system to cool the
fuel going to the engine.  Mercedes goes to all kinds of design extremes and
they have a single pass radiator.   If a double bypass was better I believe
at least some cars like Mercedes they would do it.
I have calculated the headlosses in the pantera cooling system and I changed
my radiator from a bypass system to make inlet and outlet tubes on the
opposite side of the radiator with no baffles.  My opinion is that by making
the water go through the radiator twice might slightly help the radiator
cool at idle but drastically increases the headloss at higher engine rpm's.
This headloss reduces the flow and thus the  cooling system capacity.
Rich
----- Original Message -----
From: "Guy Dellavecchia" <guido_detomaso@prodigy.net>
To: "Multiple recipients of list" <detomaso@realbig.com>
Sent: Wednesday, July 04, 2001 8:20 AM
Subject: Re: radiator


> Richard,
>
> Where'd you come up with this:
>
> > Whatever you do, don't turn it into a single pass radiator (by hooking
> > up to the other tank) as the reduced flow velocity (~ 1/4 the speed)
> > will greatly reduce the heat transfer due to lower turbulence. >
>
> First, if the radiator was evenly divided in half, which it's not on the
> stock radiator by the way, the flow would double, not go up by 4X.
>
> But more significantly, this turbulence fixation, if it had any validity,
> runs counter to the overwhelming majority of everyday experience.  Why
does
> every other car and truck on the road, with the tiny exception of
Pantera's
> and similar, use a "single pass" radiator?  I cannot think of any other
> brand with this inlet and outlet on the same side thing going on.
>
> Plus do you or anyone else really believe it "will greatly reduce the heat
> transfer"?  This would require both the surface temperature of the
radiator
> and hence the temperature of the heated air coming out of the radiator to
be
> "greatly reduced".  I cannot picture that anyone ever put their hand on a
> flaming hot single pass radiator and said "See, the skin isn't burning off
> my hand because the water isn't turbulent enough".  Nor has anyone likely
> said "I converted my heater core to a turbulating multi-pass arrangement,
> and now I can light a cigarette off the dash vents".
>
> Like the guy with the thick accent at the LV tech talk said, the metal to
> water resistance to heat exchange is trivial compared to the metal to air
> resistance.  It just makes sense and parallels the reality of the huge
> majority of cars and trucks on the road now.
>
> Guy D.
>
>
>
>