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Old 10-20-2008, 08:45 PM   #43
Opie
 
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Name: Opie
Title: Ingenuity Director
Status: Not Here
Join Date: Apr 2006
Location: Federal Way, WA
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Posts: 363
I have taken several phone calls asking what I feel the correct coolant pressure should be set at idle. Lets just lay it out here, my system does not alter coolant pressure until after 2000 rpm. There is a weep hole that keeps that basically enhances regulator flow but that really does not alter below 2000 rpm any different than stock.
It seems wrong to lower coolant pressure at rpms lower than 2000rpm range. At idle there is only 8 –10 psi and while it does increase with rpms most trucks are not over 20 psi until 1800 rpm. After 2000 rpm is when the pump pressure starts increasing rapidly. All of the other systems out right now do alter the lower rpm coolant pressures.
If one wanted to lower lower rpm pressure why not just alter the water pump fins with a couple holes of grind/blend them down or easier yet under drive the pulley? I am totally against all them ideas myself, lowering the lower rpm coolant pressure is the wrong logic IMHO. Everyone has their beliefs and people will sell you about anything these days. Again, I feel the only true way to find out what system is best is to monitor temps and a pressure gauge in the cab while testing in various load/rpm scenarios.

Running an electric pump is fine for quarter mile passes but not the right answers for the greater majority of trucks as they just don’t offer enough flow/pressure for prolonged loads. Not to mention all 12VDC electric have a record of failure and if it does so there would be very little warning and ton$ of risk to engine damage. There are very good reasons why the factory engineers use a mechanical water pump.

Interested reading from the internet:
Mechanical energy
drives the pump; this can be taken right off the crank
with a belt as is done with a mechanical pump. In
the case of an electric pump, the power comes from
the alternator, which is driven from the crank.
Rather than the crank directly driving the pump, the
mechanical energy is changed into electrical energy
by the alternator, then the electric motor on the
pump changes it back into mechanical energy to
turn the pump. Since electric motors and alternator
are not 100% efficient, power is lost in this process.
So why do we see a little more power when
switching to an electric pump when they are less
efficient? The answer is simple; they do not pump
as much. The average electric pump flows under
35gph, where the average mechanical pump flows
twice as much.
If an electric pump flows enough for the
application, it can be an advantage. The biggest
advantage of an electric pump is that it can be left
4
running with the engine off to cool it off better
between rounds. If you have a really good electric
pump that can out flow the stock pump at low engine
speeds, then you’ll have a big advantage in stop and
go traffic. I have yet to see any electric pump out
flow a stock pump at higher rpm. If you plan doing
any road racing, where the rpm stays up for
extended periods, a mechanical pump is the only
choice. Drag racing is a different animal altogether.
You may only see 9 seconds of wide open throttle,
heat may build quickly, but an electric pump and
fans can run between rounds to cool everything
down. Remember, not everything you see on race
cars means it’s better for your street car.


Anyhow, after enough required pressure is being maintained for a safe boiling point temp, with my bypass coolant flow through the engine more than doubles at higher rpms. Which is great for cooling, keeping even temp across the engine, the water pump as it works less than half as hard freeing up some power and reduces steam pockets.

So now we will probably read somewhere that if coolant flows too fast it will not have time to pick up the heat. Sorry but that statement is not true as long as there is coolant contact the rate of heat transfer is the same.

The internet covers this point as well,

Nucleate Cooling Phase:
As coolant flows through the system it
absorbs heat from the engine parts that it comes in
contact with. As it does this some of the coolant will
boil and form tiny steam bubbles (absorbing a lot of
heat in the process) on the internal engine surfaces.
When these bubbles get larger they become a flow
restriction and the flowing fluid pushes them away
from the surface and that process starts over again.
The process is called the Nucleate Cooling
Phase. When the coolant boiling point is too low or
the flow rate is too slow, these bubbles can become
too large and form steam pockets that insulate that
surface from being cooled. This usually happens
around the combustion chambers, the hottest parts
of the engine. Once the steam pocket forms the
surface will rise in temperature (even though the
coolant is not overheating) and cause that part to
overheat, which can cause detonation and / or other
problems.


Hopefully this post has given the answers to most peoples questions on this coolant bypass.

Just like all the other improvements made for our trucks it’s just a matter of time before we see other kits come out using information from above, but… You read it here first!
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