LT-1 Plumbing Info...
Throttle Body... 3 fittings on the passenger side, one on the drivers side, should be plumbed as follows...
...Passenger Side Top ... breather tube to passenger valve cover.
...Passenger Side Middle... air in from EVAP cannister.
...Passenger Side Bottom (3/8)... water in from back of heads (steam tube).
...Driver's Side (3/4)... water out to top of radiator (can T into upper rad hose).
Water Pump... 2 large fittings on top for rad hoses, 1 smaller 5/8 fitting on upper passenger side, 1 smaller 3/4 fitting on lower
passenger side, 1 smaller 3/4 fitting on lower passenger side. They should be plumbed as follows...
...Passenger Side Large Upper (1-1/2)... water in from bottom of radiator.
...Driver's Side Large Upper (1-1/2)... water out to top of radiator.
...Upper Passenger Side Smaller(5/8)... water out to heater core.
...Lower Passenger Side Smaller (3/4)... water in from heater core.
...Lower Passenger Side Smaller (3/4)... cap end of hose above head level. Use for bleeding air.
Intake Plenum... 1 fitting on driver side. Plumb to brake booster. Be sure a check valve is inline.
Carbureted "off road" applications (no way smog legal)...If you are using a carburetor with your conversion, a fuel supply loop should be plumbed in to make the hi-pressure RX-7 fuel pump compatible with the low pressure / volume requirements of your carburetor. The RX-7 fuel pump must have a constantly circulating fuel flow through it for cooling purposes. To make both the carburetor and fuel pump happy, we install a T into the fuel line, connecting the pressure and return lines together, to form a path for the fuel to circulate back to the fuel tank. The 3rd leg of the T should go to a fuel pressure regulator (available at any auto parts store), then on to the carburetor. Plumbed like this, fuel will just return to the tank through the return line without building any pressure for the carburetor. In order to get the 4-6 psi pressure recommended for the carburetor, some restriction is needed in the return line. An easy way to get this restriction is to use a pair of Vice Grip type pliers, and slowly and incrementally crimp the steel section of the return line until there is about 8-10 psi before the pressure regulator. After this is achieved, the regulator can be adjusted to further drop that pressure to 4-6 psi for the carburetor.
Port Injected applications...The stock RX-7 fuel pump is compatible in both pressure and volume for all but the most modified TPI & LT-1 fuel injected V-8 engines (injected RX-7s typically run about 45 psi of fuel pressure at the injector). Since the pressure regulator is located on the end of the engine's fuel rail, fuel pressure is automatically adjusted to the requirements of the engine.
LS1 Fuel Sytem...
The Camaro/Firebird LS1 fuel systems feature an in-tank Fuel Pressure Regulator (FPR) and require only a single fuel supply line to the engine's fuel rail, and no fuel return line. Here are a few ways to make the RX-7 compatible with the LS1...
Option 1- Install LS1 Fuel Pump & Regulator in RX-7 Fuel Tank...This option is likely to be smog legal anywhere, as long as the LS1 fuel tank pressure sensor is installed as well. Requires removing the fuel tank access plate.
Option 2- Install a Rear Mounted External Fuel Pressure Regulator...This requires using a stand alone regulator mounted just outside the RX-7 fuel tank, with the bypass/return line plumbed back into the RX-7 tank's return port. While not technically smog legal, it is easier and does the job just as well, but the non-approved part of the fuel system is hidden and not likely to be spotted by the smog referee.
Option 3- Install Corvette FPR in Engine Compartment...The Corvette LS1 uses an engine compartment located FPR with a return line. The problem is that we are not using a Corvette engine configuration, so this FPR is not technically smog legal. Since it's mounted under the hood, it's very easy to install, but also easier to recognize as a non-legal part.
Option 4- Install Aftermarket Return-Style FPR...No-way smog legal. For the big-horsepower applications. Here you are installing much larger pressure and return lines and need to use parts that have a much higher flow capacity.
Re-plumbing the RX-7's AC system is easier than one might think. We suggest that you re-use the OEM hose fittings/pipes from the RX-7 at the firewall, condensor, and drier. Re-use the OEM hose fittings for the compressor that you are using. Salvaging these fittings will not only save you money, but it will insure that you have the correct fittings for your application. The salvaged fittings will be fitted with new hose and crimp sleeves, and hose length and fitting angle can be adjusted to your exact requirements. The AC system plumbing should be routed as follows...
...large firewall fitting connects to the compressor suction port.
...small firewall fitting connects to the reciever/drier outlet port.
...compressor pressure port connects to top of the condensor core.
...condensor core bottom connects to the reciever/drier inlet port.
After the hose lengths and fitting direction are tailored to your application, return to the hose shop to have your new crimp sleeves crimped onto your new hoses permanantly.
After the hoses are attached, you can take your car to the AC shop to evacuate and charge the system.
If your completed AC system is operating under severe conditions, a small 10" fan can be attached to the condensor core to boost performance.
The electrical part of your engine conversion for the AC system is covered in the electrical section.
2....Considerations & Requirements....
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....