[LMSRACER]

This is for Information Purposes Only. These Calculations are based on a Consistent Discharge Coefficient for the Various Orifices Listed.

I've been mentioned here recently and therefore felt compelled to provide some technical information that may be of help to those interested.

I have stopped posting on this topic because, since we do make parts for pontiacs, I didn't want the Performance Years Police to punish me.

>> Here's what needs to be considered: (Initially)
1) Water Pump Flow Capacity in Gallons Per Minute.
2) Water Pump Inlet, Inside Diameter/Area.
(Should Always be Larger than the Outlet to Avoid Water Pump Cavitation.)
3) Cooling System Outlet Hose/Line Inside Diameter/Area.
(This is the Actual Orifice/Inside Diameter/Area Calculation of the Engine's Coolant Outlet.)
4) Coolant Line/Hose Routing.
(Keep in Mind that "Unrestricted" Coolant Flow Always Flows through the Path of Least Resistance.)
5) Individual Coolant Line/Hose I.D. and how it relates to the Velocity & Pressure of the Coolant.
(Actually, the I.D. of the Fitting Utilized is what's Important because the I.D. of the Fitting is Always Smaller than the I.D. of the Hose.)
6) Coolant Passage Holes/Orifices in the Cylinder Head's and Engine Block's, Deck Surfaces.
(Very Important when Adding or Plugging Holes in the Deck Surface.)

O.K., to be clear, if you are using a "Stock Block", the sizes and quantity of holes in the deck surfaces are equal to the "Approximate" flow capacity of a 1.705" Hole/Orifice.
>> Calculated from 5 x 5/16", 1 x 3/8", 3 x 7/16" and 1 x 1/2" hole per Deck Surface. <<

Therefore a "Stock Block" Deck Surface allows more than ample coolant flow and will not be the restriction to coolant flow. In fact the I.D. of a "Stock Thermostat Housing" Outlet is Approximately 1.300". That's Approximately 42% Less Flow than the Flow Capacity through both Deck Surfaces.

Here's some pertinent information relating to "AN Fitting" dimensions.
>> Necessaary for Flow Volume Calculations. <<
-8 AN = 0.390" Orifice = .11946 sq.in. Area.
-10 AN = 0.480" Orifice = .18096 sq.in. Area.
-12 AN = 0.610" Orifice = 0.29224 sq.in. Area.

Therefore:
2 x -8 AN = .23892 sq.in. Area = .5515454" Hole/Orifice (35/64" - Closest 1/64")
4 x -8 AN = .47784 sq.in. Area = .7800031" Hole/Orifice (25/32" - Closest 1/64")
2 x -10 AN = .36192 sq.in. Area = .6788305" Hole/Orifice (43/64" - Closest 1/64")
4 x -10 AN = .72384 sq.in. Area = .9600114" Hole/Orifice (31/32" - Closest 1/64")
2 x -12 AN = .58448 sq.in. Area = .86266.5" Hole/Orifice (55/64" - Closest 1/64")
4 x -12 AN = 1.16896 sq.in. Area = 1.2199862" Hole/Orifice (1-7/32" - Closest 1/64")

Therefore: (Coolant Velocity Calculations.)
>> Knowing that the Water Pump is Rated @ 30 Gallons Per Minute in this Example. <<
2 x -8 AN Fittings = 40.281 ft./sec.
4 x -8 AN Fittings = 20.141 ft./sec.
2 x -10 AN Fittings = 26.592 ft./sec.
4 x -10 AN Fittings = 13.296 ft./sec.
2 x -12 AN Fittings = 16.466 ft./sec.
4 x -12 AN Fittings = 8.233 ft./sec.

O.K., So here's what you need to consider:
1) As the velocity in the Hoses/Lines Increases, the Positive Pressure Created by the Water Pump in the Engine's Coolant Passages also Increases.
2) Positive Pressure in the Engine's Coolant Passages that is Created by the Water Pump is a "Good Thing". Not at all the same thing as "Coolant System Pressure" created by Engine Heat or by the Formation of Steam Pockets.
* NOTE: "Excessive" Positive Pressure slows the Water Pump and can Actually Damage the Pump's Electric Motor.
3) Whenever the Water Pump is Capable of Creating a "Positive Presure" in the Engine's Coolant Passages, it is of Benefit. The Idea is that the Coolant Passages are full of Pockets and Cavities that can be Difficult for the Coolant to Reach and for the Air to Escape. These pockets are Steam Traps. Temperatures in Steam Pockets Sky Rocket and can be Disasterous. The Positive Pressure Created by the Water Pump Aids in Forcing Coolant into these Areas and Forcing the Air out.
4) Never Run the Engine without the Water Pump Running. Once a Steam Pocket begins to Form it Pressurizes that Area and it then becomes very difficult to Quench that Area once the Water Pump begins to Run. Picture what happens when you pour cold water into a Hot "Cast Iron" Skillet. Now picture that same water cooling the skillet before it gets hot. One way it cools the skillet easily and the other way it's a losing battle.
5) Fabricate and Install Coolant Lines from the Rear of the Cylinder Head Outlets at the Intake Flange Surface (Factory Heater Hose Outlet Area.) to the Thermostat/Water Outlet Housing Area. Preferrably above the Restrictor that you would run in place of the Thermostat. The Restrictor's Size should be Utilized to Control the Flow of Coolant from the Front of the Engine Only.
>> If you haven't already done this, you should. <<
6) If your Engine is a "Serious Race Effort" then adding additional lines from the Center of the Heads, at the Intake Flange Area, to the Thermostat/Water Outlet Housing Area is also a must.
>> If your Heads don't have the Outlets already, then add them. <<
7) In Extreme Effort Applications, some folks, such as Scott Rex, John Langer and John Marcella are actually "Injecting Cold Coolant" through the Cylinder Head and onto the Deck Surface between the Center Two Exhaust Ports to keep the Head from getting Soft and Warping.

Here's where it gets tricky. Everyone asks, What Size Lines and How Many?
The answer relates to the Water Pump Flow, the Engine's Power Output, the Fuel being Utilized and the Plumbing Configuration.

Here's some "Basic Recommendations":
1) Belt Driven Pumps and Mechanical Pumps with the Moroso Water Pump Drive.
>> Bare Minimum = 4 x -8AN Hoses. Two from the Front and Two from the Rear. <<
(This Calculated Volume is Slightly Greater than Running a Single 3/4" Restrictor in Place of the Thermostat.)
2) 30 GPM Electric Pumps.
>> Most Racing Applications = 4 x -10 AN Hoses. Two from the Front and Two from the Rear.
(This Calculated Volume is Slightly Less than Running a Single 1" Restrictor in Place of the Thermostat.)
>> Optional = 2 x -10 AN Hoses Front. 2 x -10 AN Hoses from the Rear coming off of a "Y" Fitting where Two -8 AN Hoses are Plumbed to the Rear of the Heads and 2 x -6 AN Hoses are Plumbed to the Center of the Heads.
3) Inline Water Pumps and High Volume Electric Pumps above 30 G.P.M..
>> Three -10 AN Lines Per Cylinder Head for a Total of Six. These Six Lines Plumbed into a Coolant/Water Outlet Manifold like the One Offered by John Marcella and CSR to just Name a Couple.
4) Extreme Effort Applications = Whatever it Takes... LOL.....

For the Guys looking to keep a more "Stock Appearance", Reduce the Number of Coolant Lines and keep their Cost down, we offer components that can maintain the factory water crossover manifold in the front of the engine and the factory water outlet/thermostat housing. They're engineered so that the flow volumes are correct and the appearance is much more factory without so many hoses, fittings and exotic fabricated manifolds. They're also designed to control the coolant flow from the front and rear of the engine seperately, much the way that varying the individual hose sizes does.

One Last Note:
Configurations differ and although alot are the same, some can be exotic. I can help you with your set-up if you want me to. Shoot me a PM or an E-Mail @ oprecisionautom@carolina.rr.com...

Thanks for Listening.. Back to Work,
Larry S.