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Down Flow Radiator

The Torana down flow core is approximately W 650 mm x H 360 mm (2340 cm2). This means you are limited to twin 12” ( 300 mm ) fans or a single 14" ( 350 mm ) fan if you want to stay within the core boundary. A 16” ( 400 mm ) fan can be fitted but it will overhang the core. If you have a manual then you could line the 16" ( 400 mm ) fan up with the top of the core and let it overhang at the bottom of the radiator. This may not be an option with an internal transmission cooler as the fan may foul on the transmission cooler lines.

Cross Flow Radiator

The Torana cross flow core is approximately W 470 mm x H 520 mm (2444 cm2). Twin 12" ( 300 mm ) fans will overhang the tanks and not cover the core effectively. A single 16" ( 400 mm ) fan will fit nicely on a cross flow core, this in my opinion is the main reason to fit a cross flow radiator in a Torana. However the cross flow design does not expose as much core area to direct airflow as the down flow design in a Torana.

The main advantage of a cross flow radiator verses a down flow radiator in terms of design is that the radiator cap on a cross flow radiator is located on the low pressure (suction) side of the system, so it is unaffected by the pressure generated by the water pump.

Airflow

There is considerable debate as to how much airflow is required. Engine modifications, automatic transmissions, hi-stall convertors, transmission coolers, oil coolers and A/C evaporators all add to the load. The local climate must also be considered. In Perth I would consider 2300 cfm a good starting point.

As a general rule of thumb it appears that an 12 volt electric fan can produce between 100 and 150 cfm per 1 amp current draw. Zirgo claim their 16” fans produces 3000 cfm and draws 10 amps. SPAL claim their high performance 16” fan produces around 3000 cfm and draws 20 amps. I find the Zirgo cfm claim dubious.

Typically the alternator will need to be upgraded to a minimum of 85 amps to handle the load created by the cooling fans.

SPAL 16" on a cross flow radiator

There are several 16" SPAL fans rated between 2350 cfm and the extreme which is rated at around 3000 cfm. The SPAL extreme does not have a sealed motor and is not recommended for street use.

AU Falcon fans on a down flow radiator

The best value for money option is AU Falcon fans. Unfortunately the lip near the chassis rail needs to be trimmed to make them fit. I have also heard of people squashing the shroud between the lips on the chassis rails and trimming the blades of the fans so they do not touch the shroud. I have been told that each AU fan is rated around 1900 cfm and draw 20 amps. The AU fans cost around $250 for factory original. There are cheaper copies available however they are not as powerful. The brackets are cut off the fan shroud and 12 mm is trimmed from the depth of the shroud to move the fans closer to the radiator. The fans are mounted upside down on a V8 Holden radiator and the right way up on a Chev radiator.

Ford Mondeo fans on a down flow radiator

The Ford Mondeo fans will fit without modification to the chassis rail lips. They are more expensive than AU fans and not as powerful. I have seen Ford Mondeo fans being sold on eBay as "Twin Shrouded Thermo Fan" recently for between $150 and $200. They may just be copies with inferior fans like the AU Falcon copies or the could be OEM.

Twin Derale 16926 on a down flow radiator

I have twin Derale 16926 fans on an aluminium shroud. Each fan is rated at 2200 cfm and draws 23.4 amps. The Derale fans appear to use the same motor as the AU fan (Bosch) and a similar blade design.

SPAL Fan Controller

The SPAL fan controller FAN-PWM-V3 can be used to control one or two fans. It has an input that can be connected to an A/C circuit to trigger the fans when the A/C compressor is running. The fan controller can read some factory temperature senders or use its own sender. You can configure low and high temperature settings in the controller. When the low temperature is reached the main fan is switched on at low speed. If the temperature continues to rise the fan speed is increased. Once the high temperature setting is reached the main fan is at full speed and the secondary fan relay is triggered.

Transmission Coolers

There are four basic options for transmission coolers.

1. Internal transmission cooler mounted in the bottom tank for the radiator. This is the simplest method and requires the least space. It is typically not considered suitable for towing or high stall torque convertors. The major downside is that if the internal cooler ruptures then coolant will mix with transmission fluid and destroy the transmission.
2. External booster cooler. The internal transmission cooler is used in conjunction with a small external cooler. Factory towing packs will typically include an external transmission cooler to be used in conjunction with the standard internal cooler.
3. Stand alone external cooler.
4. Stand alone external cooler with thermostatically controlled fan. This is the Ultimate solution as the transmission fluid is maintained at optimum temperature however they are bulky when compared with other methods. B&M 70297

Coolant Filters

If you have a iron block then a radiator filter is a must.

Clean Flow Radiator Filter Sock

Tefba Radiator Filter

Radiator Links

Stewart Components Tech Tips 1-5

Aluminium vs. Copper Radiators

Top Ten Cooling Suggestions For Your Rod