Miatapower List Archive

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Mail From: (email redacted)


From: "Mel Hoagland" <(email redacted)>

>Next will come a set of SPAL dual high performance
>fans. ... My view is that the air flow
>needs to be increased through the radiator (no matter what radiator you
>have). There was a posting (don't remember who from) a few months ago
>describing a "barrier" of air that forms in front of the radiator (due to
>the restriction of the passages), when the car is moving at high speeds,
>which actually reduces the flow of air through the radiator. Made sense to
>me.

That was me. AG Bell's Book "Modern Engine Tuning" also says that for optimal
cooling at high speed, the fin count should be more like 10 fins per inch rather
than 14 fins per inch. There is a tradeoff between surface area of the fins and
flow resistance presented to the moving air. At work, in designing heatsinks
for power electronics, too many fins indeed means higher temperatures.

What's the fin count of the various hi-perf rads out there?

I also suggested making the transition from mouth to rad streamlined. That is,
create some ductwork from mouth to rad in a sort of truncated cone shape, with
all escape paths for the air sealed.

The book also says that what makes aluminum radiators superior is that Al is
stiffer, so that the tubes thru which the water passes (the holes you see
looking thru the opened radiator filler neck) can be made longer, so there's
more surface area to transfer heat to the fins.

-Jason

This read-only message was archived from a public mail list.
Mail From: "Mel Hoagland" <(email redacted)>


Do you (or anyone) have any numbers regarding the flow rate of the factory
fan?

TIA

Mel
------------------------------------------------------------
Mel Hoagland ((email redacted))
"Wheezy" black 96 FMII vrrooommmm

----- Original Message -----
From: <(email redacted)>
To: <(email redacted)>
Sent: Thursday, January 06, 2000 7:34 AM
Subject: Re: Heat Core help please! / Engine Coolers and Al rads


>
> From: "Mel Hoagland" <(email redacted)>
>
> >Next will come a set of SPAL dual high performance
> >fans. ... My view is that the air flow
> >needs to be increased through the radiator (no matter what radiator you
> >have). There was a posting (don't remember who from) a few months ago
> >describing a "barrier" of air that forms in front of the radiator (due to
> >the restriction of the passages), when the car is moving at high speeds,
> >which actually reduces the flow of air through the radiator. Made sense
to
> >me.
>
> That was me. AG Bell's Book "Modern Engine Tuning" also says that for
optimal
> cooling at high speed, the fin count should be more like 10 fins per inch
rather
> than 14 fins per inch. There is a tradeoff between surface area of the
fins and
> flow resistance presented to the moving air. At work, in designing
heatsinks
> for power electronics, too many fins indeed means higher temperatures.
>
> What's the fin count of the various hi-perf rads out there?
>
> I also suggested making the transition from mouth to rad streamlined.
That is,
> create some ductwork from mouth to rad in a sort of truncated cone shape,
with
> all escape paths for the air sealed.
>
> The book also says that what makes aluminum radiators superior is that Al
is
> stiffer, so that the tubes thru which the water passes (the holes you see
> looking thru the opened radiator filler neck) can be made longer, so
there's
> more surface area to transfer heat to the fins.
>
> -Jason
>