A cammed car is one that has been fitted with an aftermarket performance camshaft, or "cam." This modification changes the engine's valve timing and lift, which is the distance the valves open. The primary goal is to increase airflow into and out of the combustion chambers, allowing the engine to burn more fuel and air to produce significantly more power, particularly at high RPMs.
However, this power boost comes with significant trade-offs. A performance camshaft alters the engine's idle quality, often causing it to have a choppy, loping sound that is highly sought after in muscle car and hot rod cultures. More importantly, it shifts the engine's power band higher up in the RPM range. This means the engine will feel sluggish and lack low-end torque, making daily driving in stop-and-go traffic more challenging. It can also lead to reduced fuel economy and increased emissions, potentially making it difficult to pass mandatory emissions tests in some states.
The table below outlines typical changes when installing an aggressive performance cam compared to a stock camshaft:
| Performance Characteristic | Stock Camshaft | Performance "Cammed" Camshaft |
|---|
| Peak Horsepower | Optimized for balance | Increases significantly (e.g., +50-100+ HP) |
| Low-End Torque | Strong and immediate | Often reduced or "soft" |
| Idle Quality | Smooth and steady | Choppy and lumpy |
| Power Band (RPM Range) | Broad and low-to-mid range | Narrowed and shifted to high RPM |
| Fuel Economy | Better | Worse, especially under normal driving |
| Emissions Compliance | Meets standards | Often fails without supporting mods |
Installing a cam is a serious modification that usually requires supporting upgrades like high-flow exhausts, tuned engine computers (ECU), and sometimes stronger internal engine components. It's a modification best suited for dedicated performance vehicles rather than daily drivers.
