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  • Better Breathing: More Power and Better Fuel Economy For Our 2009 Ford F-150

Better Breathing: More Power and Better Fuel Economy For Our 2009 Ford F-150

Mark Williams
Oct 7, 2009
If we've learned anything from recent history, it's that there aren't a lot of people interested in buying new pickups or full-size SUVs. Although that's bad news for Ford, Chevy, Toyota, and others, companies that make products to improve efficiency and fuel economy are doing quite well.
Photo 2/22   |   1. Our '09 F-150 has Ford's three-valve 5.4-liter V-8, factory rated at 310 horsepower and 365 pound-feet of torque. Much of the engine compartment is filled with the air box (bottom) and the resonator chambers on the intake tube, both of which get streamlined with the K&N Intake Kit.
There are plenty of simple ways to improve the fuel economy of your truck, but some of the easiest have to do with improving efficiency. In fact, one of the simplest ways to improve any big V-8 is to make it a better breather. Substantial gains can be made by swapping out the (in most cases) restrictive factory air intake setup, with its multiple resonator-chambered tubing and low-flow paper filter, and substitute a higher air flow, reuseable air filter, like those offered by K&N, AEM, aFe, Bully Dog, and others. We like the idea of saving money on air filters as well as the promise of more power so we decided to take a closer look. For this scientific endeavor we enlisted our 2009 Motor Trend Truck of the Year long-termer Ford F-150 and asked the tech guys at K&N to give us exact before-and-after dyno numbers. We'd be doing some further road testing on our own.
At this point, it's worth noting that all new truck manufacturers do a pretty good job tuning their engines with equal emphasis on power and quietness. However, with so much attention to reduced interior cabin noise by new vehicle buyers, powertrain engineers work long and hard at getting as much noise reduction from the engine as possible. The results on the intake side of the engine have resulted in numerous, bulb-like chambers typically branch off the main intake runner from the filter box, designed specifically to isolate and cancel various sounds generated by the rushing and sucking air as it channels through the filter and toward the combustion chamber.
We found, once the K&N High-Flow Intake kit was installed, the engine noise levels were slightly louder and more pronounced during hard and moderate accelerations; however, idle and cruising speeds showed no noticeable changes. As a side note, our guess is that many enthusiasts may like the more throaty and raspy noise the engine makes when pushed a bit, as it gives the impression there may be more under the hood that one might suspect. We didn't find the throatier sound unpleasant at all, and appreciated the tone difference when we pulled up alongside another '09 F-150.
Photo 3/22   |   2. The factory paper filter is as large as a college textbook. Air is sucked from the driver-side fenderwell, through the paper filter, and then drawn into the throttle body. Our filter (changed just 2000 miles ago) is quite dirty, making it difficult for our pickup to get big gulps of air when needed. We would have shelled out about $15 at the local autoparts store for a new one pretty quick.
Additionally, we found a slightly quicker throttle response after installing the kit; we assume a direct result of the reduced restriction and smoothed air running from filter to combustion chamber.
On a SuperFlow rear-wheel dyno, our stock 5.4L F-150 maxed out at 241 horsepower at 4700 rpm, with 272 pound-feet of torque at 4600 rpm. Post intake kit install, we upped the horsepower to 261 and torque to 292 pound-feet, a boost of 20 in both cases. Although this might not sound like much, from behind the wheel we noticed the added power and growl. Additionally, we wanted to know how this might affect our fuel economy, as we've reports in both good and bad directions. For our test, we mapped out a 52-mile mountain loop outside Los Angeles with various stretches of two-lane highway, some freeway, a stretch of tight twisties, ending with a series of gentle curves, ranging in elevation from 1800 feet to 4200 feet above sea level. Our before and after runs were done just several days apart with an average speed within 4/10th of a mph of each other, with very similar temperature and road conditions. According to the on-board computer on our F-150 that can calculate instant and average mpg data (reset at the beginning of each of our runs, right after we topped off the tank), we averaged close to 10-percent-better fuel economy with the K&N Intake Kit, improving from 19.2 mpg to 21.0 mpg.
Photo 4/22   |   3. We showed up at the K&N headquarters and pulled onto their state-of-the art SuperFlow dyno to get some before-and-after test numbers, then we'd hit the road for our own evaluation.
The results? During our test, we got somewhere between seven- and eight-percent-better power, a stronger sounding engine, almost 10-percent-better fuel economy, all for around $350. By our calculations (15K miles/year, $3/gal fuel), with the gas savings alone, the intake kit pays for itself in 16 months. Then, if you add in the money saved by never having to buy an air filter again for as long as you own your truck, that number probably gets underneath a year. Of course, there are drawbacks. You will get a different sound from your engine you may not like, and there are certain rules you need to follow when washing and reoiling your filter (K&N sells the cleaning recharger kit separately for about $15). With all that said, making a small investment now for better breathing could be the first step in getting your truck to save you money at the gas pump. Here are some of the highlights to our install on the '09 F-150.
4. The chassis dyno measures the amount of power produced by the truck to spin the liquid-filled cylinders. The data is sent to a computer where the information can be instantly shown and saved in graph form.
Photo 5/22   |   4 Dybo Liquid Filled Cylinders

5. A simple PC computer uses WinDyn (Windows Dynamometer) V2.7 software to collect and display the collected data. Our dyno bay also had an overhead monitor and remote controller so technicians could start and view the dyno runs from the comfort of the driver's seat.
Photo 6/22   |   5 Test Computer

6. Test Bay
Photo 7/22   |   6 Test Bay

7. Data Screen
Photo 8/22   |   7 Data Screen
8. The Intake Kit for just about any half-ton pickup truck is pretty much the same--lifetime conical filter, heat-shielded filter box, intake tube, and all the adaptors, clamps, and hardware you might need. Additionally, K&N kits include any specialty tools. Figure the cost to be about $350.
Photo 9/22   |   8 K And N Intake Kit

9. The factory air intake tube is specially designed with several sound-deadening chambers off the main intake path. These chambers are intended to silence any intake noise from the engine during idle, mid-range use, or wide open throttle. Yes, they serve a purpose, but they sure are ugly.
Photo 10/22   |   9 2009 Ford F 150 Factory Air Intake Tube

10. The first step is to unclip the wiring for the Mass Air Flow Sensor on the intake tube just behind the air box. Removing the factory intake tube is as easy as loosening two hose clamps—one attaching the box; the other at the throttle body inlet tube.
Photo 11/22   |   10 Unclip The Wiring For The Mass Air Flow Sensor

11. Next, unsnap the three metal latches securing the upper air box housing to the lower air box housing. Remove the factory paper filter as well. The intake tube, upper air box, and filter will be replaced.
Photo 12/22   |   11 Unsnaping Three Metal Latches

12. After just a few minutes work, this is what you should have—a lot of open space. Be sure not to allow any debris inside the throttle body. The F-150 Intake Kit uses the existing lower air box and fender intake to draw cooler air from outside.
Photo 13/22   |   12 Open Space In Engine

13. Comparing the two filters (old on the left; new on the right) should give you a pretty good idea about size and capability. We're guessing the factory filter could flow about 500 cubic feet per minute, while the re-useable, conical filter can easily flow more than double that amount.
Photo 14/22   |   13 Comparing The Two Filters

14. Install the silicone hose onto the throttle body inlet tube. The tools necessary for the job include a flathead screwdriver and crescent wrench.
Photo 15/22   |   14 Install The Silicone Hose

15. The Mass Air sensor measures air density so the computer can mix the right amounts of fuel and air inside the engine. K&N requires the factory sensor be removed from the existing unit and reinstalled into the Intake Kit tube. An adaptor and gasket are included. If you over-oil your replaceable filter, this sensor will likely trigger a “check engine” light.
Photo 16/22   |   15 2009 Ford F 150 Mass Air Sensor

16. A special Torx wrench is included with the kit to install the Mass Air sensor. Make sure the open end of the sensor is pointed toward the filter.
Photo 17/22   |   16 Torx Wrench

17. A tube bracket and saddle clamp is included with the kit to locate and stabilize the intake tube. The locating bracket mounts to an existing bolt on the timing cover. A crescent wrench will secure the nut and bolt.
Photo 18/22   |   17 Tube Bracket And Saddle Clamp

18. The top end of the filter box secures to the existing lower air box with two of the three latch clamps. You can remove the center latch. A hose clamp slides over the intake tube and marries the saddle clamp to the tube, giving it support. The silicone hose and clamp attach the filter to the intake tube that runs inside the air box.
Photo 19/22   |   18 Top End Of The Filter Box

19. Trim pieces surround the top of the air box to create a seal against the closed hood. Likewise, trim pieces locate the intake tube through the air box wall. The final step is to the reconnect the Mass Air sensor electrical connection.
Photo 20/22   |   19 Trim Pieces

20. The before and after shots don't look much different, but our postinstall testing showed better horsepower and torque (see sidebar), a more powerful sound, and better fuel economy. . . and we'll never have to buy another air filter for our truck again.
Photo 21/22   |   20 After Shots

21. These are the exact before (blue) and after (red) results of just putting a new intake kit on our '09 F-150 half-ton. And we're told similar results are predicted for other half-ton sold in the U.S. (see box).
Photo 22/22   |   21 Dyno Chart
Small things can add up
Beyond swapping in a smaller engine, there are a few simple things you can do to improve your truck's overall fuel economy. Make one or two of these changes and you can expect to see small gains immediately. Do several of them, and they'll compound. Of course, some of the advice we offer will cost some money, but when calculated over the life of your vehicle, it's likely the up-front investment will end up paying for itself in savings. Here's our top seven. Maybe you have a few to add.
1) Dump Weight: Get rid of all the tools and gear you don't need on a regular basis. Take an inventory and be very guarded about exactly what you need for your next trip. If you don't need it, don't bring it. Check your bed, behind the seats, the door cubbies, even the glovebox. Additionally (but a more expensive proposition), consider aluminum wheels; it could save you as much as 20 pounds per wheel in unsprung and overall weight.
2) Get Lubed: Synthetic oils are slipperier and typically have longer lives. Both will save you money in the long run. Engine, transfer case, transmission, and differential synthetic oil will cost more, but they can each deliver as much as one-percent added mpg benefit when replacing petroleum-based lubes.
3) Compound Interest: We all know tire inflation is critical for peak mpg performance, but also consider researching what types of chemicals are in your tires. More and more tire makers are beginning to produce stiffer and harder compounds to get better fuel economy. Be aware of the tradeoffs—they're likely to cost a little more, have street treads, ride quieter, and have different braking characteristics than traditional truck tires.
4) Cold Charge: There are several companies making cold air boxes specifically designed to reduce the intake air temperature, thus producing a denser air/fuel mixture, which will make a more efficient and powerful combustion chamber burn.
5) Smooth Wins: Be aware of your driving habits and try to smooth out your stops and starts. The worst thing you can do is not pay attention when slowing down and taking off from a start. Most of your mpg wins and losses are decided by how aggressive you are in these two common driving situations.
6) Injector Inspector: We'll assume you keep your vehicle in good health with regular filter and oil changes, but going one step deeper into the injectors and spark plugs can also help a great deal. Check the plugs once a year to make sure you're getting a clean burn. Excess carbon buildup could mean a spitting injector. Likewise, clean injectors will mean a more efficient burn.
7) Breaking Wind: As any over-the-road trucker will tell you, streamlining your aero is critical. Take a look at your truck as if you are the wind. What can the wind grab onto? Lightbars, storage racks, and spot-lights might look good and be functional but it creates mpg-robbing turbulence behind your vehicle. Additionally, OEs have spent a lot of money testing in wind tunnels to measure how your pickup cuts through the wind--keep your tailgates up.
More Power with an Intake Kit
Although exact pricing will vary and each installation kit is slightly different, expect to pay around $350 for a half-ton K&N Intake Kit, with the average install time (assuming you have all the needed tools) ranging from 15 to 45 minutes. Below are the K&N recorded results from their own horsepower before-and-after tests.
Toyota Tundra 5.7L V-8 -- +14 hp
Chevy Silverado 6.0L V-8 -- +18 hp
Ford F-150 5.4L V-8 -- +16 hp
Nissan Titan 5.6L V-8 -- + 14 hp
Dodge Ram 5.7L V-8 -- +11 hp
GMC Sierra 5.3L V-8 -- +17 hp
By the Numbers (box)
Stock F-150 Peak Horsepower 241.4 @ 4700
Stock F-150 Peak Torque 272.1 @ 4600
Stock F-150 Fuel Economy 19.2 mpg
Intake Kit F-150 Horsepower 260.8 @ 4700
Intake Kit F-150 Torque 291.8 @ 4600
Intake Kit F-150 Fuel Economy 21.0 mpg
Horsepower Increase 8.5%
Torque Increase 7.3%
Fuel Economy Increase 9.4%

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