Throttle body basics
Like the carburetors of old, a throttle body acts as the link to your ride’s motor by metering how much air enters the engine. You press the gas pedal, and it pulls a cable that’s attached to the throttle body’s moveable plates, which are known as “butterflies.” In newer cars, the cable has been replaced by a potentiometer on the gas pedal and an electric motor on the throttle body. This is called “drive-by-wire.”
No matter what throttle input style your car has, as you open and close the butterflies in the throttle body, you’ll change your engine’s airflow, and as a result, its power output. But, in some cases, your car’s throttle body can be too small to satisfy the engine’s demand for fresh air — even with the butterflies fully opened.
How to shop for a performance throttle body
The solution to uncorking your restricted ride is to bolt on a performance throttle body with a larger internal bore. This allows more air to pass through and your engine to generate more horsepower. Now before you grab the biggest throttle body you can, keep in mind — airflow isn’t the only factor in generating horsepower. A balance of air volume, velocity and turbulence in the engine must be maintained or you’ll lose horsepower. That’s because vastly increasing the potential of one aspect decreases the other two factors.
In some cases, you’ll notice several different throttle body sizes available, and in your choice of millimeters. This is the internal bore size of the throttle body and will have a different impact on what RPM your ride will make its maximum horsepower. Generally, the bigger you go, the higher you’ll have to rev the engine to notice a difference in power. And, if you bolt on a throttle body that’s too big, your ride will feel sluggish at low RPMs and will take off like a missile as soon as the engine’s airflow demand matches the size of the throttle body.
That being said, unless you’ve bolted on a bunch of mods to boost your ride’s horsepower and how much air it truly needs, going with a slightly larger throttle body is your best bet. This gives you the extra performance you want, without any trade-offs like sluggish acceleration. Here are a few key points to remember when shopping for a performance throttle body.
- Make sure the throttle body you’re looking to purchase is emissions-legal in your state.
- Be conservative when choosing a throttle body. If you plan on keeping your car near-stock, go with an only slightly larger throttle body. Bigger isn’t always better.
- Plan your future mods before ordering a new throttle body. Some mods like a supercharger will need a larger throttle body to work properly. So, if you’re going to add serious, power-building mods to your ride in the future, give yourself some wiggle room when it comes to potential airflow and grab a bigger throttle body to begin with.
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