Cooling Last Update: May 4, 2009 11:01 PM

The Old Radiator

I had a Flyin' Miata aluminum radiator in the car for my turbo setup. It is bigger than the stock radiator and designed to handle a lot of heat (my exhaust gas temps were close to 1700 degrees max). It is 16x26x2 inches. I was hoping I could re-use it for for the LS1 but turns out I can't. Well atleast not easily and one of the main reason is the location of the inlet and outlet of the radiator in relation to them on the LS1.

In these pictures you can see that fans are off but the stock radiator brackets are on.

If you look carefully, you can see the stock radiator brackets as well as the red capped LS1 coolant inlet and outlet which are both on the passegner side of the engine.

One of the bottom fan bungs hits the crank pulley and leans the top of the radiator back about an inch as is seen in the above pic.

This is the radiator still leaning backwards. You can see the interfering bung.

This is the radiator in the stock location. Thats about a quarter of an inch clearance.

Above you can see the two small heator core connectors (top left), the LS1 inlet (half cutoff middle right), the LS1 outlet (middle left down by the heater core connectors) and the radiator outlet (center bottom). It hard to tell in this picture but the idler pulley is in front of the radiator outlet and thus it is imposible to put a coolant hose on the radiator. This can be solved by moving the radiator forward but you also have to get the radiator inlet all the way over to the passenger side of the car so I am just going to get a double pass radiator so both the inlet and outlet are on the passenger side.

Here you can see the interference that would occur if a coolant hose was on the radiator outlet. It would hit the belt pulley.

The Custom Radiator:

I had a radiator custom made by PRC Inc in Douglassville, Ga. It is 24.5x16x3 and uses the stock radiator bracket holes to attach. You can call Shane at PRC and order my radiator. Racing Concepts is now using this radiator as their kit radiator. He will be making an option to add AC to the kit that will use the miata condenser mounted to this radiator and custom hard lines that will attach to the ls1 compressor. I removed the stock radiator brackets and bent the AC condensor brackets 90 degrees backwards.

The front is right up to the hood latch.

As you can see, all the welds look great and I am very happy with the results.


The Coolant Hoses:

I also had PRC Inc supply the fan and in-line filler. I got the coolant hoses from my local auto parts store. I used trial and error to find ones that would fit. The top hose just needs two 90 degree bends.

This is the hose I used for the bottom. All I had to do was cut an inch or so from the bottom connection (one with label) to make it fit. It does not contact any parts of the car so it should work. NOTE: This hose does not work with the LS1 AC Compressor.

ls1 engine miata

I added some nylon sleeving to protect the heater hose lines from abrasion. Also note the throttle body cam stop modification. It is ground down about 1/8 inch to allow the throttle body plate to go truely parrallel with air flow. Stock it only goes about 78 degrees (rather than the full 90)

The Cooling Fan:

I got the fan from PRC Inc. It is 16 inches in diameter and mounts with platic connectors that go through the radiator.

Its a very tight fit but it does fit. The LS2 crank and water pump pulley have a lower profile and would alott more room but I just stuck with the stock ls1 ones as they do fit its just tight..