Sitting between your engine's air filter housing and intake manifold, a throttle body assembly exists for the purpose of controlling how much air enters a fuel-injected engine. Inside the throttle body housing, a butterfly valve (hinged metal plate) determines the airflow rate by rotating open so that more air can pass through when the accelerator pedal is depressed.
As that air passes through a round, tube-shaped section of the housing, information is gathered from various sensors and relayed to the engine's control computer. This data is then used to calculate an ideal fuel mixture for the amount of air flowing in.
Compared to an OE-equivalent throttle body, a performance-oriented throttle body can help your engine create more power (and who doesn't like more power?). In this article, we'll look at 4 ways that performance throttle bodies can benefit any car enthusiast.
For a more detailed look at a typical throttle body layout, function, and installation, we invite you to read our related article What Is A Fuel System Throttle Body?
An engine is really nothing more than a big air pump. Everything else being equal, the more air we can pump through it, the more power it will make. Performance throttle bodies are built with airflow tubes that are larger in diameter than OEM ones. Naturally, this increases airflow. Throttle bodies are given an airflow rating based on the number of cubic feet of air that can pass through in one minute ("CFM" for short). Use this rating as a gauge when making your selection.
Packing more air into your engine allows more fuel to be burned, which creates more power. Because aforementioned sensors measure the airflow rate, the car's engine control computer can take note of this increase and up the amount of fuel delivered to the pre-combustion chamber. Peak air-to-fuel ratio (14 parts air to 1 part fuel) that produces the most complete combustion is maintained, maximizing power gains.
It's important to note that if the air-to-fuel ratio should deviate in either direction, loss occurs. For example, pumping more fuel into an engine without a corresponding increase in air would not produce more power - only unburned fuel going out the exhaust pipes. Likewise, adding air without increasing fuel will cause a "lean" running condition and a noticeable drop in power.
We recommend choosing the largest throttle body sizes only if you've made fuel delivery and high-power modifications to your vehicle. Otherwise, you'll be adding more air than the fuel system can keep up with. Power gains will be disappointing. If your vehicle is stock or "mildly" modified with a cold air intake or a cat-back exhaust, for example, go with a slightly larger increase over OEM size.
Improved Throttle Response
When you consider that a throttle body is just a valve, it's easy to understand how a performance throttle body yields quicker throttle response. Most auto manufacturers measure airflow at peak rpm's, then choose a throttle body diameter to ensure that 50% throttle will produce exactly 50% airflow. This results in a more gradual response that drivers who are NOT interested in performance would value, because they equate it with smooth drivability.
Because the butterfly valve on a typical performance throttle body is designed to open proportionately wider at low rpm's, power is created with less delay. When you combine that steeper response rate with additional torque produced by the engine, you get a sharper bite that's noticeable at low rpm's.
You'll Get More Out Of Other Power Modifications
If you've made engine modifications that produce more power through the use of forced air induction (superchargers and turbochargers), the greater airflow ability of a performance throttle body will really do your engine justice. In effect, an engine that has been modified to breathe better will be looking for more air, and a larger throttle body will deliver exactly what these other mods are looking for.
Other modifications that can see additional gains from performance throttle bodies are exhaust headers, performance air intakes, and even electronic tuners that remap spark timing and fuel delivery.
Throttle Bodies We Offer
We've got a large selection of performance throttle bodies, most of which are crafted from lightweight aluminum. To name just a few for more recent vehicles, the Holley Billet LS Throttle Body covers a number of 1997-on Chevy cars and trucks equipped with LS-series V8 engines. We've also got the BBK Power-Plus Series Throttle Body (wide selection of makes & models) and Jet Powr-Flo Throttle Body (2003-15 GM & Ford) throttle bodies.
If you're looking to upgrade an older vehicle already equipped with fuel injection, we've got the Skunk2 Alpha Series Throttle Body (best value), Pro Series (higher performance) and the Blox Racing aluminum Billet Throttle Body for Honda and Acura engines from the 1980s through today. The Holley Hi-Flow EFI Throttle Body covers assorted Dodge, Ford, and GM V8s from 1986-on, while their 2-Barrel Performance TBI is for GM pickups from 1986-95. The BBK Power-Plus Series Throttle Body covers Chevy and Ford back to 1985, and it's even got a version for 1957-58 Chrysler Imperials with the rare early mechanical fuel injection.
If you'll be upgrading your classic from a carbureted setup to fuel injection, you're going to need a throttle body assembly to replace that carb. Fortunately, we've got throttle bodies from Edelbrock (track use only) and Holley designed with just this adaptive ability to mount on square bore intake manifolds where a carburetor once sat.
For those who wish to maintain the original look of a carburetor, the Holley Terminator Stealth EFI Base Kit even looks like one from the outside!
Think of a performance throttle body as the new-school version of the performance carburetor (you may even recognize some of these brand names if you're old enough to have played with carbs back in the day). On a value-per-dollar basis, a throttle body upgrade delivers a lot of additional fun for your money!