I don't recall how much more flow the Edelbrock pump claims. They did have
some graphs either in their catalog on online, that compared their pumps to
other "hi performance" pumps. The pumps were flowing around 45 cfm at 5krpm
IIRC.
I read that article in the Cat notes a while back. It made no sense then,
and it really makes no sense now, in light of my experiences. I think you
are right on in your thinking, slower flow means more chance for the water
in the block to heat up. The faster you push the water thru the system, the
more BTU's you can reject. And getting rid of heat is the bottom line,
Temp is just how you keep score.
Now lets talk about thermostats for a moment.
I fooled around with one on the stove a few months ago. I found that the
thermostat would start to open at the temp labeled on the thermostat.
It required about 15 degrees higher temp to reach full open
A 160 would crack at 160 and not be wide open until 175.
A 180 would not be wide open until 195.
So if your temp is in that window the thermostat is controlling flow rate to
keep temp in range.
Before I replaced the pump, I was using a 160 F thermostat. In easy driving
in the mornings the car would warm up and run right at 170 degrees. It was
stable and very consistent. It could never really run less than 170.
After the pump was replaced, the car would run at 161 or 162 degrees under
the same conditions. What is going on? My explanation is that the old pump
required the thermostat to be wider open to get enough flow to reach
equilibrium. The new pump is capable of generating much more pressure and
hence flow. The new pump could find equilibrium with the thermostat more
fully closed. The new pump was pushing more water thru the system with the
thermostat more fully closed than the old pump was capable of doing.
I have learned that the Tiger requires a complete cooling system to keep its
cool. All the pieces must work together. I had all the mods that everybody
says are necessary for a cool cat, and I still overheated on the freeway.
Then I changed the pump and BANG, cool cat. My experience does not match
the comments made in the TE/AE article on cooling. They found the water pump
was not a big player in cooling off a tiger. That article is part of what
kept me from playing with the pump for a long time. Maybe the pump that was
in my car was just worn out or defective in some way. Maybe I could have
solved the problem with just a stock water pump replacement. I don't know.
Erich
----- Original Message -----
From: "Tom Witt" <wittsend@jps.net>
To: <tigers@autox.team.net>; "Kathy and Erich Coiner" <kathy.coiner@gte.net>
Sent: Tuesday, August 12, 2003 9:13 AM
Subject: Re: Cooling System Acid Test
> Erich,
> Sounds like you got the job done with the desired results! I am curious
> about the water pump. Do you know how much more the Edelbrock flows than a
> stock pump (percentage or volume wise). There is interesting information
in
> the CAT Shop notes that regards using a pump with less impeller blades to
> slow down the rate the coolant flows through the radiator. The thought is
> that the coolant doesn't get enough time to loose it's heat because it is
> going through the radiator too fast and returns to the engine. I have
always
> considered the thinking ("slow flow") suspect because the rest of the
"slow
> coolant" is in the block/heads etc. just getting hotter! Your results
would
> seem to rebuke the thinking behind the "slow flow" position, hence, my
> curiosity about the flow rates of the stock vs Edelbrock water pumps.
Though
> even there, regardless of the flow rates, I would think that the
thermostat
> opening (or actually restriction there of) might negate any flow increase
> with a higher volume pump. I'm probably just thinking too much and should
> let real world results speak for themselves, but when I try to follow this
> to a logical conclusion I just ......... . Perhaps there are just too many
> variables (coolant flow rate, radiator size and ability to disipate heat,
> air circulation through the radiator etc.) and any one improvement (in you
> case coolent flow) might be capable to compensate for a deficientcy in the
> others.
> Regards, Tom Witt B9470101
>
> ----- Original Message -----
> From: Kathy and Erich Coiner <kathy.coiner@gte.net>
> To: Tiger List <tigers@autox.team.net>
> Sent: Sunday, August 10, 2003 3:03 PM
> Subject: Cooling System Acid Test
>
>
> > Today was a nice hot day in Poway CA (96 F on my patio)
> > I took the Tiger out for a spin with my son. When we got back I left the
> car
> > idling in the garage. After 20 minutes the temp was 201; after 30
minutes
> > it was 205.
> >
> > When the test started the garage was 96F, when it was over the temp was
up
> > to 100F. Yes the door was open, and the tail of the car was outside in
> the
> > sun.
> >
> > I then drove it around the neighborhood for a few minutes and it cooled
> > right down. Less than 3 miles of 25-35 mph with stops had the car back
at
> > 185.
> >
> > I have a thermocouple mounted in the hot tank of the radiator. That is
the
> > source of my readings. It also confirms that my dash gauge is way more
> > accurate than I would ever expect.
> >
> > I am declaring victory in my battle against tiger overheating. (I have
> owned
> > the car for 22 months. So it did not give in easy)
> >
> > Now I need to train myself to watch the scenery and not the temp gauge.
> >
> > The combo that is working for me is:
> >
> > Near stock 260 with 4 barrell and headers.
> >
> > 3 row radiator with surge tank connected to the cold tank on the
radiator.
> > (Available from list member Rob Guera)
> > Stock Tiger radiator shroud
> > Derale rigid fan 17515
> > Water pump pulley from Ford Fairmont. (smaller in diameter, runs fan and
> > pump faster)
> >
> > LAT hood
> > Edelbrock hi flow water pump
> > Horn block off plates
> > water pipe insulation jacket stuffed between radiator bottom and cross
> > member (stops a lot of the hot air that recirculates thru the radiator
at
> > idle)
> >
> > Cut out sheet metal strip that blocks off about 4 rows of the radiator.
> >
> > Aluminum air ducting between lower valance and radiator core support. I
> > followed the instructions in Steve Laifman's "Cool it Buddy" article.
> > This ducting ensures that any air that enters the front of the car can
> only
> > go thru the radiator core. It also means that any warm air that wants
to
> > recirculate into the radiator must travel forward to the inlets in the
> > valance and not just curl around the bottom of the radiator.
> >
> > I can say that the water pump change made the most dramatic difference
in
> my
> > car. Without the pump the car would overheat on the freeway and run
warm
> in
> > stop and go traffic. The pump was the last thing I did, so I cannot
> comment
> > on how important all the other pieces of the sytem are. Without the
pump
> > nothing works. With the pump and everything else, I have the problem
> > nailed. I leave it to somebody else to figure out if anything I did is
not
> > worth much.
> >
> > Erich
> > getting cocky and thinking about A/C
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