>From herbie ford-trucks.com Thu Oct 1 06:10:47 1998
Date: Thu, 1 Oct 1998 06:10:47 -0400 (EDT)
From: owner-perf-list-digest ford-trucks.com (perf-list-digest)
To: perf-list-digest ford-trucks.com
Subject: perf-list-digest V1 #105
Reply-To: perf-list ford-trucks.com
Sender: owner-perf-list-digest ford-trucks.com


perf-list-digest Thursday, October 1 1998 Volume 01 : Number 105



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Ford Truck Enthusiasts - Performance
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In this issue:

FTE Perf - Long cooling ramble
Re: FTE Perf - Long cooling ramble
RE: FTE Perf - Long cooling ramble
FTE Perf - Cheap 100 horsepower for a 1996 2x2 f-150 w/302 and auto trans w/3.55 ratio?
FTE Perf - Model TT dump truck
FTE Perf - ADMIN: Your story in a Ford truck book

=======================================================================

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Date: Wed, 30 Sep 1998 09:42:02 -0700
From: "Chris Samuel"
Subject: FTE Perf - Long cooling ramble

"Technically, as long as the water is in contact with the block heat
transfer is happening at the same rate regardless of water speed but the
speed causes more turbulence and I think it's the turbulence that causes the
problem not speed by itself. Technically, more speed means more
cooling......IF the radiator can dispose of it."

Said Gary.

This thread is just too much fun and causing me to read too much!

The thermal transfer between any material and water happens at a rate of "X"
time/Thickness/in.sq.to raise water temperature 1 degree F. So as you can
see there is a time differential to this equation. To achieve maximum
cooling the goal is to remove maximum heat from the engine, so the coolant
should be as hot as it can be when it gets to the radiator. Or stated
another way the Delta T between the inlet water and the outlet water should
be as high as possible with in the design limits of the system.
This is going to happen only if there is enough time to fully BTU load the
coolant.
The issue of turbulence is one where turbulence is actually desirable and
the properties of laminar flow will in-fact reduce cooling.

"Put a big enough radiator on it, take out the thermostat and run enough
volume past the surfaces in the engine and it will run COLD not hot from a
physics stand point but as you said the turbulence causes areas where there
are lots of restrictions and turns to actually cavitate which is what is the
real culprit IMHO."

Gary said.

But in the real world this is often only what appears to be happening. In
reality there can be a wonderful amount of flow and yet the engine
overheats. The key is a mixture of both flow and pressure and time; not just
one of these.

"Heat moves from the block to the coolant at the same speed or rate no
matter what based on only two things I know of: Temp difference between
the two mediums and time. If the water moves too slowly the temp difference
will diminish causing a loss in efficiency but if the coolant is separated
from the walls for an instant here and there then the time element is
compromised which is what turbulence does."

Quoting Gary again.

The rate of transfer is not constant as I understand it. Not because the
rate that the metal gives up heat changes but because colder water accepts
heat at a slower rate then hotter water. Ok we are splitting hairs but...
If the water moves too slowly then the water will boil and yes that is a bad
thing. The turbulence issue is not true up to a point. Picture this if you
will: The flow of water out of a hose. If viewed as a cross section The
walls of the hose being the water jacket. If the temperature of the water is
measured the boundary layer will be higher then the center temperature. The
observation also correlates that the flow will be slower at the outside then
the center.
If the flow is increased to some point the center will simply not change
temperature as it is moving too fast, while the outside may boil. What we
want is to have turbulence so that we get the center of the flow to deflect
and scour the boundary layer off the walls, and the hot boundary layer is in
the center so to speak. Yes too much turbulence is a bad thing but it is
fairly hard to do with OEM pieces. And again the flow rate is designed to
have a t/stat restricting it.


Again Gary said:

"I'm sure most OEM cooling systems are perfected through trial and error
based on these phenomena. Run it too fast and you get good transfer but
may cavitate some areas of the heads causing hot spots and "after boil" on
shut down etc.. Run it too slow and you will have even cooling but may not
be enough transfer to keep the engine cool enough."

This has been a topic that is so misunderstood and difficult to grasp as to
drive one knutz!
Slowing the water in the block and heads is deliberate. This is because you
are not "Cooling the engine" by putting cold water in. You are cooling the
engine by taking heat out. A small difference in wording but all important.
The temperature of the water is not important up to a point.
The temperature of the engine metal is important.
The amount of heat that is removed by the water is important.
The amount of heat dissipated by the radiator is vary important.
The physics of the model are that you want to be able to remove enough heat
from the engine to hold it at a specified or design temperature; no more no
less.
The easiest way to do this is to size the system so that it is capable of
holding the engine operating at maximum design output for a designed amount
of time, at a designed temperature, on an "Air Standard Day".
The inlet and outlet temperatures need to reflect the coolant picking up a
full BTU load in the engine and a full reduction across the radiator. Here
you have two time factors, and yes flow rates. The thermostat is the method
that is used to regulate the temperature when operating at less then maximum
output and to give quick warm times, or operate on other then standard days.

The Cooling system is something that I am still grappling with. I am sure
that I do not understand it completely. What I do understand is that almost
all of my preconceived notions were wrong. I do want to say that I am in no
way picking on Gary, he/you simply and eloquently stated everything that I
used to believe and understand; 4 years ago I would have agreed totally!)

Here is one for you. 5.0L w/GT 40 heads making say 350HP appeared to be ok
but there were issues with Pre IGN/ detonation. Increase the HP and suddenly
the metal overheats, head gaskets "fail", water in the oil. Cool the engine
and no leaks. Yet the water temp was ok until after the damage was done!
Everyone in these racing classes is failing engines; Gee I wonder why!!!
What this shows is exactly what I was saying above. But in examining the
problem Gary was right too as the water jackets in this head simply put
SUCK. Ford FUBAR big time! The passages are way too small and convoluted to
be effective on anything other then a low power output street engine, they
do not have adequate flow! So the water can reach temperature saturation and
flash to steam. The pressures locally go way high, steam finds any way out
and so leaks past the gasket into the valley. Cool it down and the steam
goes away the gasket re-seals and the problem appears to go away. The temp
of the water may not rise because the total of the water flow temp. didn't
it only overheated in the heads. So you might not understand why you are
having IGN problems and you might not see the water in the oil as it would
evaporate perhaps before you next changed it. The problem would be blamed on
the IGN or fuel systems.
So what we have is a case where the coolant did not pick up its BTU load due
to the pressure in the head overriding the water pressure. In this instance
the problem is as Gary said the flow is incorrect. But not due to the t/stat
but due to the shear stupidity of Ford. The t/stat FWIW has no effect on
this problem.
Cooling systems gotta love them. Make or break any engine. More critical
then they have been credited for by a vary long shot!

Later
Chris


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------------------------------

Date: Wed, 30 Sep 1998 13:52:40 +0000
From: "Gary, 78 BBB"
Subject: Re: FTE Perf - Long cooling ramble

From: "Chris Samuel"
Subject: FTE Perf - Long cooling ramble
Date sent: Wed, 30 Sep 1998 09:42:02 -0700

> instance the problem is as Gary said the flow is incorrect. But not due to
> the t/stat but due to the shear stupidity of Ford. The t/stat FWIW has no
> effect on this problem. Cooling systems gotta love them. Make or break any
> engine. More critical then they have been credited for by a vary long
> shot!

Run a 351C engine with no thermostat housing restrictor and tell me what
happens? I don't know why it happens but I know it happens, virtually every
time, why?

A son-in-law only takes part of a daughter away,
Dad keeps the best part :-)

- -- Gary --


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------------------------------

Date: Wed, 30 Sep 1998 14:02:25 -0400
From: Sleddog
Subject: RE: FTE Perf - Long cooling ramble

chris posted-

The thermal transfer between any material and water happens at a rate of
"X"
time/Thickness/in.sq.to raise water temperature 1 degree F. So as you can
see there is a time differential to this equation. To achieve maximum
cooling the goal is to remove maximum heat from the engine, so the coolant
should be as hot as it can be when it gets to the radiator. Or stated
another way the Delta T between the inlet water and the outlet water should
be as high as possible with in the design limits of the system.
This is going to happen only if there is enough time to fully BTU load the
coolant.
The issue of turbulence is one where turbulence is actually desirable and
the properties of laminar flow will in-fact reduce cooling.

i say: that is one aspect i was trying to say. though i feel too much
turbulance is too bad (because of cavitation). laminar flow and turbulant
flow also may co-exist in irregular and strange shaped passages such as
water jackets in an engine. i have no evidance for this other than my
education and imagination. lmainar flow does exist in turbulant flow, next
to the boundry up until sufficiently large reynold's numbers. the
thickness is irrelevant. the solid (head, cylinder) is assumed a constant
temperature becasue the resistance to heat flow is less here, than in the
solid to fluid boubary, where it is *much* larger. same applies to water
jacket thickness as long as total available water volume is sufficiant. it
is this boundary that is the biggest restriction to heat flow. therefore
the conditions here are most important inside the h20 jacketing, and the
radiater itself.

chris posted-

"Heat moves from the block to the coolant at the same speed or rate no
matter what based on only two things I know of: Temp difference between
the two mediums and time

i say: i'd like to add, that the heat transfer equations are different for
laminar and turbulant flow as far as i can remember. my old heat transfer
book is behind me on the shelf, but i know if i open it i'll spend 3 hours
reading and writing up another post. no time for that now! also different
eqauitions apply for different situations and the relavance of all of the
forms of heat transfer such as radiation, convection, conduction.

as i remember it, the greater temperature difference can be likened to
having higher voltage in a curcuit. it is a higher potential for energy
transfer.

also, the thermostat creates a genreally open/closed system, not a constant
flow system thru the radiater as one would expect. put a t-stat in water
on the stove with a thermometer. watch it. it opens/close fully and
(relativly) quickly, never staying at any partially open state.

restrictor plates BTW create a more stable cooling system when properly
done because of this.

pressure helps prevent steam pockets and cavitation, also increases the
actual btu each unit of water can "hold", but mostly does the first 2
things. it only increases actual btu ability at boiling point, by, you
guessed it, raising the boiling point over that of atmoshperic pressure.

on a side note: i feel that a head temperature gauge stuck into the water
jacketing would be a better indication of actual engine temp, than a
regular place in the front of the engine.

sleddog



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------------------------------

Date: Wed, 30 Sep 1998 14:29:43 -0500
From: "palspaugh"
Subject: FTE Perf - Cheap 100 horsepower for a 1996 2x2 f-150 w/302 and auto trans w/3.55 ratio?

I am in the market for a cheap route to giving my truck at least 100 more
horsepower without nitrus. Does anybody have any suggestions? Also I would
like advice on doing a suspension lift, like what products to use and also
tire sizes. I have heard that maybe the Twin I-beams would have to be
replaced, is this true?

- -
Regards,

Peter Alspaugh
alspaugh_p metairie.whlinder.com

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------------------------------

Date: Wed, 30 Sep 1998 21:57:01 -0400
From: Ken Payne
Subject: FTE Perf - Model TT dump truck

If anyone is interested, there is a Model TT dump truck
for sale for $4100 obo on the web site. Its on the main
classifieds page, scroll to the bottom and you'll see
a picture of it. The owner is about to retire to Florida
and asked me to announce it to the group. Given the fact
that they need to get rid of it, the price is probably
pretty flexible.

Ken Payne
== FTE: Uns*bscribe and posting info www.ford-trucks.com/faq.html

------------------------------

Date: Wed, 30 Sep 1998 22:41:30 -0400
From: Ken Payne
Subject: FTE Perf - ADMIN: Your story in a Ford truck book

Hi everyone, I receive the following email from someone. I thought
it would be a good idea to pass it on to the lists. Contact Judy
about this (address below), not me.

Ken Payne
CoAdmin, Ford Truck Enthusiasts

>>From jcscott ican.net
>Reply-To:
>From: "judy scott"
>To:
>Subject: Tough Tales
>X-MSMail-Priority: Normal
>
>Hi Webmaster,
>
>You and your members can see their name in print and
>get a Free copy of Tough Tales (working title). Here's
>how. I have a contract to publish a book comprised of
>a brief history of the F-series trucks, a glance at their
>ads, and STORIES BY OWNERS OF F-SERIES TRUCKS.
>The latter is where you and your members can
>contribute. All owners whose stories are published will
>see their name in print and receive a FREE copy of
>Tough Tales. THe kind of stories I need will tell about
>my love affair with my Ford truck, why I love my
>Ford, how I got my very first Ford truck, my grandma's
>ole Ford, I'll never forget the day/night....,etc.
>
>Tough Tales is the people side of the awesome F-series
>trucks. I'm ready to roll with it but need more stories.
>Would you consider publishing my request on your
>site?
>
>Look forward to your response.
>
>Judy Scott : )
>
>PS: I have subscribed to the 1997 and up digest and....


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