Troubleshooting the Cooling System...

Air Flow Control...Whatever radiator you decide on, if you live in one of the warmer climates such as Arizona or Florida, you will need to pay extra attention to directing every last bit of air drawn in by the fan THROUGH the radiator, instead of around it. This means sealing off all the paths above, below, and around the rad with sheetmetal, cardboard, or foam. The main objective of airflow control is to MAXIMIZE the pressure differential between the front of the radiator (you want it as HIGH as possible) to the area in back of the radiator (you want it as LOW as possible) to maximize airflow thru the radiator core. A key component vital to accomplishing this goal is to seal the radiator so that the core opening is the ONLY way for air to flow from the front to the back side of the radiator. Any other openings will allow air to pass around the core and will bleed off the pressure differential and ultimatly hurt airflow thru your radiator core. Look for alternate flow path above, below, or around your radiator. This is very important for cooling at ALL speeds, and should not be overlooked. REMEMBER...the RX-7 has a small engine compartment with minimal exit paths for the hot air to escape from. If the air canít get out fast enough from the rear and bottom of the engine compartment, it will simply go around the rad or fan to the low pressure area in front, reducing the amount of fresh cool air drawn in. Our radiator kits use the largest possible radiator without requiring major modifications, and our radiator brackets are engineered to seal off the paths around the rad without further fabrication.

Thermostat...Be sure to use a new high quality thermostat that features a balanced design. One almost necessary modification to your new thermostat is that a 1/8Ē diameter hole should be drilled thru the flat area of the disc to allow more thorough purging of any air bubbles when adding coolant. This mod also makes the process much faster, as the bubbles can now travel thru the closed thermostat into the upper radiator hose.

Hood weather-stripping...another exit path for the hot underhood air is at the rear of the underside of the hood. The weather-stripping there can be removed, allowing some of the hot underhood air to escape upward during slow speeds in stop and go traffic. WARNING... although this mod will result in additional removal of hot underhood air, this path will also allow underhood substances a direct path to the surface of your windshield. Oil film or steam from a blown hose could result is severely reduced visibility. Remember...this modification is only effective at low speed "stop-n-go" conditions. At higher speeds, it can work against you, as hi-speed aerodynamics cause pressure to build up at the base of the windshield, which will cause air to flow BACKWARDS into the area under the hood, pressurizing the engine compartment, causing reduced airflow thru the radiator core.

Bleeding Air From The Coolant...It is VERY important to bleed ALL air from the cooling system. This often means searching out any internal high spots that are likely to collect air, forming pockets. It is also important to have an effective coolant recovery tank to collect excess coolant as it comes up to operating temperature, and return liquid coolant to the system as it cools off and contracts after shutdown. The pressure cap is a vital component here, forcing expanding coolant to build pressure but relieving excess pressure to the recovery tank. The cap also has to have an effective secondary seal to the upper part of the radiator neck so that the contracting coolant in the system can siphon make-up from the expansion tank instead of air from the outside. If air gets in the system, the expansion of the coolant will not build up much pressure (remember that air is compressible), resulting in a lowered boiling point. Pressure from liquid coolant expanding up to the releif pressure of the radiator cap is a good thing. Pressure from low pressure coolant flashing to steam results in a downward spiral that can only be stopped by shutting off the engine. Aviod air in the system at all costs.

Chin Spoiler or Air Dam...in addition to the tips on airflow control above, an effective "chin spoiler" or "air dam" is an important tool to help maximize the radiator core's front-to-back pressure differential. The main advantage here is that the spoiler or dam keeps air in front of the car, increasing pressure to the front side of the radiator. It also keeps air from getting under the car, where it could pressurize the engine compartment and kill airflow thru the radiator core.

Next page....

1....Introduction....

2....Considerations & Requirements....

3....Getting Started....

4....Engine / Transmission Installation....

5....Exhaust / Throttle Cable / Accessory Drive / Pulleys....

6....Cooling / Fuel Systems....

7....RX-7 Wiring Harness Connector ID and Circuit Locations....

8....Electrical System Modifications By Circuit....

9....Start-up / Troubleshooting....

10....Upgrades....

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