Edelbrock Intake Heater Hose Fitting
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I'm sure the turbo guys will be thrilled to know that they will get improved intercooler performance via cooler intake temps at the manifold if they would just slow down the flow of fluid that is extracting the heat from the intake charge so that IT rises more in temperature between inlet and outlet. 
it’s time over area…I’ve said it before. one day it will sink in . but maybe not with you
Last edited by CANADIANOLDS; Aug 18, 2024 at 02:39 PM.
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Without a pressure differential between one end of a pipe and the other, fluid will not flow. Thus, a cooling system that is the same pressure throughout cannot be flowing fluid. It is the localized pressure differential (created by the pump) that gets the fluid flowing. Thus, localized pressure in a system with flowing fluid may be quite different depending on flow, pressure and restrictions at any given point. A heater core is a substantial restriction in the system, thus is it not hard to create pressures much higher at its inlet than the radiator cap limiter (which is on the suction side of the pump, thus the lowest pressure point in the system).
Think of the cooling system as an electrical circuit. The pump (battery) generates a pressure differential (voltage) across the system (load circuit). Adding a restrictor in the intake manifold fitting that feeds the heater core is like adding a resistor in series with a light-bulb (heater core) that reduces the flow (current) through the heater core. Less coolant flow through the heater core results in less pressure differential between the inlet and outlet (which also goes to the suction side of the pump). I suspect that this restrictor also forces more fluid flow through the passenger side head since there is less flow through the heater core bypassing that critical section of the cooling system.
Think of the cooling system as an electrical circuit. The pump (battery) generates a pressure differential (voltage) across the system (load circuit). Adding a restrictor in the intake manifold fitting that feeds the heater core is like adding a resistor in series with a light-bulb (heater core) that reduces the flow (current) through the heater core. Less coolant flow through the heater core results in less pressure differential between the inlet and outlet (which also goes to the suction side of the pump). I suspect that this restrictor also forces more fluid flow through the passenger side head since there is less flow through the heater core bypassing that critical section of the cooling system.
it moves coolant along like a paddle wheel on a boat. it’s also not rated by head pressure like a typical centrifugal pump because there is basically no head pressure/lift height needed in a car system.
another thing , for all intensive purposes, a liquid can’t be compressed. So in a closed liquid system , pressure is equal everywhere and in all directions.
if the cap is a 16 pound cap, the heater core is at 16 lbs, the rad is at 16 lbs, the heads, block and everything else is at 16lbs. there is flow in the system without the coolant being at different pressures….because,,, you can’t compress a liquid
get it? 😂😂😂😂
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From: Ft. Wayne, IN
Look, I agree that water cannot be compressed. That does not prove in any way that within a given water-filled system that pressure is equal everywhere. For any fluid to flow though a pipe (or hose or head or heater core) with zero pressure difference between inlet and outlet defies the laws of physics. Additionally, your "hypothesis" that slowing the flow of fluid (be it air or water, at a given inlet temperature) on one side of a heat exchanger results in increased energy flow from one side of the heat exchanger to the other also defies the laws of physics. Lets see if your Canadian education was sufficient that it allows you to follow along with this heater core analogy:
If cool air is flowing through a heater core, the temperature increase it experiences is a function of:
1: the net average temperature of the heater core (higher core temp ==>> higher air temp increase)
2: the interacting surface area (pipes and fins) between the two sides of the heater core (more surface area ==>> higher air temp increase)
3: the temperature differential between the inlet air and the interacting surface area (larger temp differential ==>> higher air temp increase)
4: the flow-rate of the air through it (higher flow rate ==>> lower air temp increase)
The air doesn't care how much water is flowing though the other side of the heater core, ONLY the temperature if the interacting surfaces (pipes and fins).
As the hot water flows through the heater core, its energy is spent increasing the temperature of the interacting surfaces (pipes and fins) until the cooling action from the air on the other side causes the system to reach thermal equilibrium. Since the hot water is giving up heat as it travels through the core, the inlet temperature is going to be higher than the outlet temperature. Thus, the net average temperature of the heater core can be approximated by the average of the inlet and outlet water temps.
So if the flow rate of the hot water is decreased, do you think the water outlet temp will increase of decrease? Since the water spends more time giving up its heat as it travels more slowly though the core, the outlet temp will decrease. This will cause the temperature at the outlet end of the heat exchanger to also decrease. Well guess what, that causes the net average temp of the heater core to decrease, which will cause the temperature of the air exiting the other side of the core to also decrease. This is the opposite of your "hypothesis":
The factory restrictor fitting is to slow down the flow through the hearted core ..that’s it. it’s meant to allow the fan to have better heat transfer across the heater core.
the main reason is when testing was done, the temp drop across the heater core was not sufficient to provide the desired heat for the interior. So instead of designing a bunch of different heater cores, they used a reducer to slow down the flow to allow the coolant to stay in the core longer, that provides a higher temp drop..not pressure drop …which means more heat to the interior.
Last edited by JohnnyBs68S; Aug 23, 2024 at 01:41 PM.
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