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How a fan upgrade can net you more HP and MPG

By Dan Sanchez

Reduce the weight and gain more power. It’s a common practice in racing and is evident in the fact that NASCAR Cup Series racecars don’t have back seats, carpet or even air conditioning. Although reducing weight is a must for race cars to go faster, does it have any effect on an 8,000 lbs. street-driven diesel pickup truck? Throwing out the back seat and adding a fiberglass hood may not yield any real results on your daily driven truck, but according to Flex-a-lite, removing reciprocating mass at the engine, will make big improvements.

Flex-a-lite, is a manufacturer of automotive aftermarket cooling systems. The company advocates replacing the heavy steel fan and clutch assembly with an electric fan system, in order to gain back horsepower and improve engine efficiency. The company says that some diesel fan and clutch assemblies can weigh 30-lbs or more and by reducing this load on the engine and replacing it with only a 28-32 amp load on the alternator is a good swap. Both independent dyno results and those from Flex-a-lite, have shown that you can gain back as much as 27 horsepower and 37-ft.lbs. of torque in some cases.

An example of this is one of the company’s diesel fan systems for Cummins equipped Dodge Ram pickups. The system consists of two 15-inch, lightweight high-flow fans made from injection molded, glass-reinforced nylon. The two fans sit in an aluminum shroud that is designed to fit in place of the factory unit and flow 5500cfm. The fans are operated from a Variable Speed Control unit that can change the fan’s output from 66 to 100 percent, depending on temperature and A/C use.

Although it’s not a complicated task to replace the clutch fan, it does take some time to accomplish. It’s necessary to drain the radiator fluid so that the top radiator hose can be temporarily removed from the upper portion of the radiator. The factory shroud easily unbolts from mounting tabs on the radiator but the reservoir and overflow tanks must also be removed. Depending on the year of your Dodge, a single bolt holds the fan and clutch assembly on the engine’s drive pulley. This may take a breaker bar with the right size socket to remove but it can be done. Once the fan is out, you will have to remove both the factory fan and shroud together.

Next, the overflow and reservoir tanks are transferred onto the Flex-a-lite aluminum shroud before the entire unit is slipped into position between the radiator and the engine. Moving some of the hoses out of the way, the Flex-a-lite fan system goes in and is bolted in the factory location. The instructions also show you how to wire the Variable Speed Unit, which requires a 12-volt ignition-on source, a ground and a lead that taps into the A/C activation power switch. In all the installation is relatively simple, but takes 4-6 hours, as it is a slow process.

Aside from extra horsepower and torque, Flex-a-lite claims that fuel economy is also improved up to 6 percent, which can equal out to more than one mile per gallon. Furthermore, the dual fan system only draws 28-36 amps and you can also adjust the temperature at which you want the fans to come on automatically.

Flex-a-lite manufactures two fan systems for Dodge Rams, the #262 fits 1994-2002 model pickups, while the Flex-a-lite #264, fits 2003-’08 models. Both systems retail for under $700, which ends up paying for itself in the first year in fuel savings alone. From what we have seen, the system works great and makes a difference in performance you can actually see. Flex-a-lite however, doesn’t recommend using any electric fan if you do lots of heavy-duty towing. The systems aren’t recommended for CGVW (combined gross vehicle weight ) over 18,000 lbs. If however, you use your diesel on the street most of the time and for towing CGVW’s under 18,000 lbs. then the added power and fuel economy is a plus that you can actually pay for itself.

Flex-a-lite Consolidated
7213 45th St Ct E
Fife, WA 98424
Flex-a-lite Consolidated Performance Products

Loosing the weight from your Dodge Cummins’ heavy fan clutch can yield an increase in power and fuel economy.

The Flex-a-lite fan kit #262 fan kit fits 1994-’02 Dodge Ram pickup trucks and includes two 15-inch electric fans, aluminum shroud, Variable Speed Control unit and all of the necessary hardware and instruction for easy installation.

The Flex-a-lite fan kit #264, fits 2003-’08 model Dodge Ram pickups and comes with everything you need for installation in 4-6 hours.

By removing the bolts along the sides of the fan shroud, you can then have better access to remove the clutch fan. Once the fan is loose, both the shroud and fan can be removed from the vehicle.

Drain the radiator and remove the radiator overfill and reservoir tank from the shroud. These transfer over to the new Flex-a-lite aluminum shroud.

The top radiator hose must be disconnected to allow room to slide the Flex-a-lite fan system between the radiator and engine. A buddy can help make the job easier without damaging the radiator or the shroud as it is positioned into place.

It’s a tight fit and you may have to push away some hoses for the Flex-a-lite shroud to fit into position. You will also have to reposition the overflow tank onto the new shroud.

With the Flex-a-lite fan system in place, it simply bolts onto the radiator brackets that held the factory shroud. Reconnect the hoses and refill the radiator.

The Variable Speed Control unit can be adjusted to turn the system on at any temperature setting you choose. It is activated by a temperature probe that fits into the radiator fins and when the A/C is turned on. The instructions detail how the wiring is attached and the kit includes wire loom and all of the necessary terminals.

Once it’s all wired, the truck is switched on and the fans begin to blow. This Dodge saved more than 30 –lbs. and got a 1.1 mile per gallon improvement in fuel economy from this simple upgrade.


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