SVTP E-fan Install – Reducing Weight and Recovering Power
Imagine the following scenario:
You have a nice shiny 2004 Lightning. Since you bought your truck you have steadily added mods to it. You have a Kenne Bell supercharger, BilletFlow throttle body and 2.73 upper pulley, JLP cold air intake and upper plenum, Afco dual pass heat exchanger with fans, P-Fab intercooler coolant reservoir, and full Dynatech exhaust system with high flow cats. With this combination you have made well over 450hp to the wheels. You realize that you are already beyond the safe limit of what your stock engine should be able to withstand.
With that in mind, what do you do when you want some new engine mods? Since you’ve ran out of safety margin for adding “big power” mods where is the next place to look? This is the exact situation I faced a little over a year ago. I came to the conclusion that the next task I should turn my attention to was increasing the efficiency of the drivetrain.
With the Lightning there is definitely room for improvement when it comes to drivetrain efficiency. Due to the sporty nature of the vehicle it is sometimes easy to forget that it’s a truck. As such, the Lightning shares many heavily built components that were designed with durability and longevity in mind more so than sportiness.
Two of the easiest places to see this overbuilt philosophy in action on a Lightning are the cooling fan and lower supercharger pulley. First, the stock mechanical fan is rather large and heavy, and it is driven by the engine. Forcing the engine to turn the fan introduces parasitic drag into the drivetrain. Second, the stock lower supercharger pulley is a heavy beast. Like the fan, it leads to parasitic loss through its significant mass being translated into rotating mass.
With these inefficiencies in mind, I made a call to Lightning Force Performance to obtain one of there well know electric fan kits. A second call was then made to Metco Motorsports for an interchangeable lower pulley kit with a stock sized (7.5 inch) ring. With these parts in hand I headed down to Anderson, SC to Amazon Tuning Solution’s facilities to measure the effectiveness of these mods on their Mustang chassis dynamometer.
When setting up the parameters for this test Rick Erdman of Amazon Tuning and my self attempted to maintain the test conditions as consistent as possible. We tried to make sure the engine coolant temperatures and intake air temperatures were the same for every run we made. This was a very difficult goal to reach, but we did get fairly close to achieving it.
First, we made a baseline run on the dyno. The results are as follows:
Stock
Eng Temp----150
IAT 1 --------88
IAT 2--------102
HP-----------474
TQ-----------514
Second, we removed the stock lower pulley and replaced it with Metco’s machined aluminum system. The Metco kit was very complete (even so much as coming with flywheel lock tool) and machined in the same high quality manner I have come to expect from all Metco products. During the replacement procedure we weighed the stock pulley and the Metco ring and hub assembly. The weights are:
Stock Lower Pulley and Cage Assembly – 10.0 lbs
Metco Pulley Assembly – 4.0 lbs
While the full weight of the stock unit is not seen by the engine as rotating mass, the cage portion of the assembly is merely static weight, there is still a 6.0 lb net reduction of weight.
Pulley Run 1
Eng Temp----160
IAT 1 --------92
IAT 2--------118
HP-----------463
TQ-----------500
Pulley Run 2
Eng Temp----168
IAT 1 --------90
IAT 2--------108
HP-----------473
TQ-----------510
We did two separate runs with just the pulley because we saw a loss in power during the first run. This was most likely due to heat soak. So we allowed the truck to cool down and made a second run. The result was that we lost 1 hp and 4 ft/lbs of torque. Again this was probably due to heat soak, but it also demonstrates that the gain, if any, from the pulley by itself is likely so small that it can not be accurately measured on the dyno.
Finally, we installed the LFP electric fan kit. LFP's fan kit includes genuine Ford parts such as a new F150 shroud and 18" dual speed fan. This, combined with the factory style weather proof wiring harness, allows the kit to have a very stock appearance. This kit is very complete and relatively easy to install with the supplied instructions. One other feature about the LFP kit that is worth noting is that it includes a toggle switch that allows the user to control the functions of the fan. This is significant to drag racers who wish to speed the engine cool down process between runs at the track. The most difficult part of the installation is removing the stock fan. After getting the assembly bolted up we ran the truck again.
Fan + Pulley
Eng Temp----158
IAT 1 --------94
IAT 2--------104
HP-----------480
TQ-----------518
This run gave use a total increase over the base line of 6 hp and 4 ft/lbs of torque. The IATs and engine temperatures were substantially similar to those of the baseline run. Therefore, this would appear to be the difference in power that can be seen with a lightweight lower pulley and electric fan kit may add. One thing that should be noted is that during each of the runs we never got the engine hot enough to activate either the electric fan or the clutch on the mechanical fan. Had the clutch on the stock fan been operating during the baseline run the difference in power would likely have been greater.
The stock fan assembly weighs in at 7.4 lbs. This weight was completely removed from the engine. Combining both of these mods also gives a total reduction of 13.4 lbs. This total loss of weight is very welcome on the Lightning because not only is the Lightning a heavy vehicle but it carries most of its mass over its front wheels. These mods remove weight exactly where it’s needed. Removing 13.4 lbs may not produce a change that can be felt in the seat of the pants, but every little bit helps.
It should also be noted that removing the electric fan gives you an opportunity to replace the stock cast iron water pump. I replaced mine with a Navigator unit, which is constructed of aluminum, purchased from Tousley Ford. The stock pump weights 8 lbs versus the Navigator unit at 4 lbs. This allowed me to move a total of 17.4 lbs from the front of my truck. Again, not a huge gain in power or loss of weight, but every little bit helps.
Finally, I would like to mention that there is likely a gain in fuel mileage that could be seen by installing the LFP electric fan kit. When cruising at highway speed in moderate temperatures the electric fan typically remains inactive. Conversely, the stock fan spins continuously while the engine is running. This should allow for better mileage. However, at this time I have not gathered enough empirical data to make a definitive determination concerning this hypothesis.
- SID297
