Both present in internal combustion engines, carburetors and fuel injection systems accomplish similar tasks. However, when comparing carburetors vs fuel injection, it is important to note the two function differently. Carburetors may be a thing of the past, but many people still prefer the more traditional method of powering an engine. In comparison, fuel injection is a newer technology, one that eventually replaced carburetors and made them obsolete in modern vehicles.

The simple design of a throttle body spacer coupled with the promise of big performance boosts makes this tiny mod seem almost too good to be true. Here’s how throttle body spacers work, and which cars are likely to see the biggest gains.