F150 Throttle Bodies Explained

The job of the throttle body found on your F150 is quite simple. It allows air to pass from the intake tube into the intake manifold. Basically a cylindrical bore with a plate, a throttle body regulates the amount of air flowing into your engine, and thus, regulates at what speed your engine is turning.

Early model 1997-2004 F150 pickups had mechanical throttle bodies, connected and controlled via a cable between the accelerator pedal and the throttle unit itself. Newer F150 pickups, 2005 and later, have a fly-by-wire system, wherein instead of a direct connection between the pedal and the throttle body, a computer receives input from the accelerator pedal and sends a corresponding signal to an actuator installed on the throttle body in order to move the throttle blade.

Realistically speaking, there isn’t anything inherently wrong with the factory throttle bodies. Well, actually, there was that whole extended warranty/recall ordeal in regards to premature failure, but that was centralized on other Ford and Mercury vehicles and not the F150.

The issue with the stock throttle body is a question of efficiency, a question of restriction. As is always the case, Ford must consider many variables (not only performance) when designing a component for any vehicle. Things like reliability, economy, cross-compatibility and cost to manufacture are major concerns that result in a throttle body, while effective, may not be completely optimized in terms of raw performance. 

Aftermarket throttle bodies are typically larger than their OEM counterpart. The idea behind this is with a larger throttle body, there ​will be more flow and volume capacity entering the intake manifold (and subsequently the combustion chamber), and therefore your F150 will see an increase in horsepower and torque.

• What you will get: Upgrading your F150 with a larger than stock throttle body will boost throttle response across the RPM range and will net a small power gain (5-7 horsepower) at higher RPM due to better flow at these levels. Moreover, a larger aftermarket throttle body will support more horsepower (via other mods) via increased flow capacity. It is a base modification needed to support heavy modifications that produce gobs of horsepower. In the case of an F150 – something like a supercharger. Combining an upgraded throttle body with an aftermarket tune will yield better results than just slapping on the throttle body itself. In the case of the latter, a combined yield of 10-15 horsepower can be expected.

• What you won’t get: Outfitting your F150 with a larger throttle body and expecting a massive increase in torque and horsepower is only setting yourself up for disappointment. As explained above, throttle bodies don’t work like this. They support horsepower – not make it.

One other thing to mention in regards to an aftermarket throttle body is the sound. Akin to throttle body spacers, some throttle bodies may produce a more noticeable sound as the air passes through, perhaps even whistling lightly. Some people love this kind of sound, whereas others find it more annoying. Food for thought.

Just like exhaust size, throttle body size is important too. Too small and your F150 will choke. Too large and the flow velocity will be too low causing lazy response. So how do you find that sweet spot? Well it depends. For stock engines that intend to remain stock, one size bigger than OEM will suffice.

For example, both 4.6L and 5.4L V8 engines are equipped with a 70 mm throttle body from the factory. Both engines will be equally responsive to a 75 mm throttle body, with an emphasis on the 5.4L as it has an extra 0.8L of displacement over the 4.6 yet still uses the same OEM 70 mm throttle body. It is not farfetched to think the stock 70 mm on the 5.4L is acting as a restriction point.

The 3.5L EcoBoost is also equipped with a 70 mm throttle body (NOT the same part # as the Triton V8s – they do not interchange) and aftermarket support has seemed to fixate on a mild increase to around 73 mm.

With the 5.0L Coyote V8, there is more choice. Rolling out the assembly plant with an 80 mm throttle body, aftermarket 85 mm and 95 mm throttle body units are available for Coyote powered F150 pickups. The former, at 85 mm, is a solid choice for stock to moderately modified trucks. The second option, at 95 mm, is more suited for F150s that have extensive modifications, such as cylinder head work or supplementary forced induction.

Can you install a larger throttle body on your bone stock F150? Absolutely! And you’ll reap the rewards of better throttle response, perhaps a more intoxicating intake sound and an extra 5-7 ponies in the upper part of the RPM band. There isn’t really a downside unless you woefully oversize the throttle body in relation to your engine, which, realistically speaking is difficult to do because apart from the 5.0L Coyote, there are only one or two sizes available for the EcoBoost and Triton engine families.

Truth be told, the power of an aftermarket throttle body lies in combination with other parts. The potential of a larger, more responsive throttle body is really only realized when installed with power adding parts such as a new exhaust system (headers included), cold air intake, and a tune. Together, these modifications make an upgraded throttle body well worth it and can easily add over 30 horsepower to the wheels.