The more air and fuel your Jaguar XJS engine can inhale (within a proper ratio, of course), the better the performance you can expect. A large-bore Jaguar XJS throttle body will help solve half of the equation by allowing much more air into your engine. In some cases, it's a good idea to match the intake manifold bore to the throttle body, and if you're using your factory manifold you may need to purchase or fabricate a throttle body adapter for ease of installation. In either case, a larger throttle body is a great addition to a turbo kit or even a heavy-breathing naturally aspirated setup.

In their simplest form, Jaguar XJS throttle bodies are basically just large butterfly valves that are metered by the engine's ECU, which then decides how much fuel to match up with the amount of air that the throttle body is allowing into the engine. When modifying an engine, however, the standard Jaguar XJS throttle body can sometimes reach a point where it is no longer large enough in diameter to supply a sufficient enough amount of air. An aftermarket Jaguar XJS throttle body can remedy this through its larger-than-stock bore, eliminating the stock unit's bottleneck effect.

Q: What is a throttle body? Why buy a throttle body?
A: Air travels through your intake piping through your throttle body and into the intake manifold. The throttle body, which includes a throttle plate that opens and closes as you press and release the throttle, can be a major bottleneck to air flow on some trucks. A larger throttle body allows more air to pass through, thus creating more power.

Q: How do you install a throttle body?
A: Throttle bodies are easily removed by taking off the factory bolts holding it in place along with all the sensors. Re-connect your sensors to your new throttle body and then install the aftermarket throttle body for power gains.

Q: What is a throttle body? Why buy one?
A: According to wiki, "In a fuel injection engine, the throttle body is the part of the air intake system that controls the amount of air flowing into the engine, in response to driver input. The throttle body is usually located between the air filter box and the intake manifold, and usually attached to, or near, the mass airflow sensor." Aftermarket throttle bodies are designed to let more air through, and simply put more air equals more horsepower. If you want more power, buying a performance throttle body is a great way to go.