Selecting Radiator Fan Type, Size, Cooling Capacity and Mounting Options
Using an electrical fan provides some definite advantages over your typical belt-driven engine fan so if you are considering fitting one to your vehicle then here are few pointers to help you choose the right fan for your application.
Firstly as a belt driven fan is only going to spin as fast as your engine low end rpm cooling abilities so is not quite as good as it would be with an electric fan where the airflow is more consistent. Another big advantage of electric fans is that you won’t see any horsepower drain because these are electrically powered as opposed to being driven off your engine power you're not going to lose any HP as the fan spins. You can use these fans as primary or auxiliary coolant sources as they can fit a little bit more easily into your engine bay depending on the available space.
A few things to consider when you're choosing an electric fan, to start with there are different styles these are:
- Pusher
- Puller
- Push / puller or reversible fans (SPAL fans are not reversible)
On SPAL fans the last letter of the part number denotes if the fan is a pusher (blowing) or puller (suction):
The pusher style mounts on the front of the radiator toward the front of the vehicle and pushes air flow back into the radiator. Puller style mounts on the backside of the radiator and draws air through the radiator core. The push/pull or reversible style obviously gives you the option of going either way so you can either use the pusher setup or puller setup.
So which is better for your application, well most cooling system manufacturers or radiator manufacturers will tell you that puller styles offer a little more efficiency, so if possible go with the puller style especially if that's your primary coolant source. If you're adding an electric fan as an auxiliary cooling source you can use a pusher style.
You can also run a shroud on the pusher side as this will reduce the amount of radiator core that has the airflow pushed onto it but the shroud may actually get a little bit in the way. One other exception on the puller style electric fan if you have a like a four row radiator a real thick core radiator a lot of companies recommend you don't use the puller style. As this may be too much of a struggle to draw that air through because of the thicker core. In which case you may want to consider going to push style in those applications.
Once you've decided on a style of electric fan (push, pull or reversible) there are a couple other considerations. Perhaps the most important among them is airflow or how much air you're going to push or pull through your radiator measured by CFM (Cubic Feet per Minute). There are a few rules of thumb for a 4-cylinder engine, ideally you should be looking at a fan that's going to deliver between 1300 and 1600 CFM. If you have a 6-cylinder engine then you’ll need to be up in the 2,000 CFM range and for v8 engines, if you have a smaller cubic inch v8 2800 to 3000 CFM. For larger cubic inch of v8 engine you're going to be looking at 4500 CFM range, it can go up from there depending on the size of your engine.
Lastly the most important consideration is going to be the size you have to work with in the vehicle or the size of the electric fan and how it all fits together. One of the advantages of electric fans is they come in all kinds of different sizes from slimmer profiles to those with different widths and heights. You’ll need to match the fan up to the space you're working with but again as a general rule of thumb you want to make sure that you have about 70 percent coverage of your radiator core with the fan.
Another consideration for people who may be concerned with excessive fan noise is the blade shape, this is where s-blade electric fans come in compared with straight bladed fans. It is debatable as some customers don't notice the difference but typically some manufacturers push s-blade fans as being a little bit quieter when they are being used, so if noise is a consideration you might want to consider one of those.
We can supply a wide range of quality SPAL axial cooling fans, centrifugal blowers and associated accessories at competitive prices all available with worldwide delivery.