Airaid Intake Install on our Diesel F-250

We have all heard the claims, “Gain 20-30 horsepower just by bolting on our doo-dad” or “Increase your fuel economy with the latest in nano-technology, it plugs into your cigarette lighter…” but how often have you seen real-world proof of these claims from an independent source? Well, here you go – we recently had a 2000 Ford F-250 in the shop getting a tune-up and had a brand-new AIRAID intake system too, which lead to us thinking, “Wouldn’t it be nice to put this on the dyno and see if this really works?”, so we put it to the test.

The key to this system is removing restrictions. In order for an engine to operate, it needs three things – fuel, air and a spark. Inhibiting or restricting any one of these parameters always ends up costing power and fuel economy. Increasing one or more of these parameters is how you gain horsepower.

The F-250’s factory airbox and air tube are functional, but they could be better. The flex tube that connects the airbox to the throttle body has corrugations that cause turbulence in the air stream, which hurt air flow. This needs to go.


The factories engineer the stock intake system for maximum sound reduction and by doing so reduces airflow.

The factory air box and tube are less than optimum, the air filter is certainly capable of cleaning the incoming air, but the corrugated air tube creates unwanted turbulence in the airstream that reduces the incoming air velocity. The airbox itself is also part of the problem, limiting the potential volume for the engine right from the start. ”The factories engineer the stock intake system for maximum sound reduction and by doing so reduces airflow,” said Chris Thomson of AIRAID.  Opening up the airbox and converting to a more free-flowing air cleaner can do wonders for helping an engine breathe.

AIRAID Improves on the Stock Intake Design

AIRAID Ford F-250 7.3L Diesel Air Intake PN# 401-246


• Synthemax Dry High Performance Filter
• Comes complete with new Urethane Battery tray
• Increases performance and mileage
• Easy to install with simple hand tool

The AIRAID systems use computer modeling to test the air flow characteristics to maximize performance. When asked about the how they design a system, Thomson told us, “On mass air-controlled vehicles we put a lot of effort in finding the ‘Sweet Spot’ to locate the sensors at. This is critical for maximum, trouble free performance. On average it takes four to six weeks from the initial design to a system in the box.” Once designed, the R&D team builds and installs a system which is then dyno tested and tuned for efficiency. This yields a fit and finish that looks factory installed, but with all the performance benefits of the aftermarket. The kits also come with a lifetime warranty, which means they stand behind their products.

Straddling a better-flowing airbox and tube with a cheap filter is not a good idea. AIRAID includes a premium filter with each system to ensure your system performs as stated. These filters are quite nice, with a pliable urethane body and a special filter material combined with cotton gauze layers. The best part is that you only have to buy one, as the filters are washable, you just need a simple cleaning kit. Cleaning the filter is super easy, it only take a few minutes to renew its performance. “We offer both oiled (SynthaFlow) and non-oiled  (SynthaMax) filter media that is backed up with a lifetime warranty,” said Thomson.

The AIRAID website features customer testimonials that share stories of increased power and better fuel economy, some sound crazy. One customer that claims his fuel economy went from 17.5 to 25 MPGs, all from just installing a new air filter and inlet tube. AIRAID tests each system on their in-house Mustang Dynamometer to validate the actual performance of each system.

Installation and Dyno

First the top of the airbox and the air tube were removed. Don’t trash it. You might want to disconnect the battery cables too. Next, the battery cover comes off. That is a serious battery hold down. The battery tray is actually part of the airbox. The 4 bolts in the bottom of the airbox have to come out so that the battery tray/airbox assembly can come out.

Comparing the original assembly to the new one, you can see some big differences. Besides the janky plastic the factory piece is made of, the Ford assembly loses some potential air volume. The AIRAID assembly is made of light-gauge steel and is more open, taking advantage of the thinner (and stronger) material to make room for more volume. AIRAID calls this assembly the CAD (Cool Air Dam)

This is why you don’t junk the stock stuff. The original air temp sensor was transferred to the new assembly. We dropped the CAD into the truck and threaded in the bolts, leaving them loose for final adjustment. The engine bay is already looking better with the CAD in place. Note that the CAD still uses the factory inlet on the radiator core support. This means you still get fresh cool air into the engine, unlike some other kits that allow hot engine-bay air get into the filter.

Next, we installed the new throttle body air tube, with the factory filter minder swapped over, and set in place. The AIRAID filter mounts in the air box to the air tube.

We installed the battery using the more convenient hold down bar supplied in the kit. Other than the AIRAID decal, this looks like it could be factory. There is a rubber trim piece that seals the airbox against the hood. This keeps the hot engine-bay air out and the cool air in.


Enough about the system, the real story is: does it perform like they say? Is it easy to install? Does it really make more power with just a simple bolt-on air filter? We dyno’d the 2000 Ford F250 on a Dynojet chassis dyno to get a solid baseline. In stock form, the F-250 made 204 hp and 424 ft lbs of torque. Then we installed the kit and with no other changes, the truck made 17 more horsepower and 19 ft lbs of torque.

While that is a pretty good gain from a simple swap, what makes it more interesting is that the gains are not just at the top, they are across the entire RPM range, and the top end shifted up about 500 RPM. Both measurements not only increased, but also flattened out a little, so they continue to make power longer before dropping off. In fact, at the tail end of the power curve, there is almost a 50 horsepower difference between the before and after, and you will certainly notice that kind of change. Regardless if you needed the extra power to pull your race trailer or just to hot rod around town, AIRAID gives you an easy to install and affordable solution to the horsepower bug!

Article Sources

About the author

Jefferson Bryant

It is almost terrifying the breadth of Jefferson's technical abilities. A fabricator, master technician, engine builder, paint and body guy, dirt track racer, road course driver, or a glossy magazine reporter, Jefferson can do it all. Oh yeah, he's also a YouTube hero.
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