Aftermarket radiator fans

[NigelC]

I was thinking of replacing the stock fan with a SPAL 9" thermo fan in my 1979 GTV (Group S) to increase the airflow through my radiator and I was wondering if anyone else has done similar.  Can you fit the fan to the exisiting shroud?

Any advice would be gladly recieved.

[Typhoon90]

I've found the cheaper brands of fans work just as well as the super expensive ones. As an example, I cool my modified Volvo 740 Turbo with a $50 "16" fan. The blade shape is important, the "schitmar" shaped blades are way, way more efficient than straight blades. Also, compare fans on cfm AND motor size, the larger the diameter of the motor, the more torque it produces, all esle being equal.
When I had my ROver P6, I ran two small 10" fans diagonally across teh core and that also worked very well. Again, just cheap fans. It should be noted the fan in my Volvo is now four years old, so no longevity issues.
I also control my fan with the Jaycar controller, I've built three before this one and they are really reliable units.

Regards, Andrew.

[MD]

NigelC,

What ever fan you decide to install, it should be one with a shroud which makes them more efficient.To eliminate blow by around the circumference of the shroud where it is close to the radiator fins, install some door seal rubber. It seals against the fins forcing all the drawn air to come through the radiator.

These fans are on a home made rack.

[djm411]

Are you having cooling problems while racing or while driving around the pits?

[NigelC]

Just about to re-build engine, expected to get a significant increase in power and torque but will also produce a lot more heat.   I turn the fan off when racing.

I have also bought (but not yet fitted) a 3-core 18fpi radiator core, so I will have no dramas while racing but it also requires a fair bit of effort to get air flowing past the core when in the pits or on the dummy grid.

[MD]

3 core rads work well on 12-13 FPI. More than that, they only work well on the move.

[John A Pucak]

Hello Nigel,been there with overheating engines ,  I think you might need a 3 core radiator / high flow or what ever they call them. The fan is only good for the pits or whilst driving on the road (like my Alfetta). you might want to try a late series fan and shroud , they aren't as thick and do the trick

John

[djm411]

Nigel,
On radiators, as MD said, seal around the radiator and fan shroud to ensure that any air that comes in the front of the car goes through the radiator. On fan sizing in a race car, i personally would avoid using a bigger fan as that may restrict air flowing through it on the track, I'd be going for a smaller fan that still pulls in large volumes of air when puttering round the pits

It would be a good idea to also look into a good sized oil cooler as this will assist the radiator in removing heat from the engine. and always allow enough space either side of the oil cooler to allow flow, if you have it hard up against the radiator then you transfer heat to and from the radiator and also restrict air flow through the cooler. An oil cooler can also help prevent lower oil pressure problems when idling round the pits as it helps reduce the thinning of the engine oil.

[NigelC]

Thank you all for the advice.  I settled on a 9" straight blade Craig Davies fan and (with a little modification) was able to use the existing shroud.

Nigel