Even if you've improved your engine's breathing capability with an intake, cylinder heads, headers, and performance exhaust system, you still won't be getting the full benefit of these mods if the valves don't open and close at the right time, or don't open long enough or far enough to allow the optimal quantity of gases to flow. The camshaft controls valve operation, and few other components have as much impact on engine performance.
OE camshafts are designed for the vehicle's factory configuration, and if you've modified your vehicle and/or have specific performance goals, your engine can produce much more power with an aftermarket performance camshaft. From increased mileage to towing, better street performance and a “lumpy” idle, to all out racing, we have the right grind for every application including hydraulic and solid, flat tappet and roller lifters.
Along with the mods listed above, compression ratio, transmission type, differential gearing, and vehicle weight must be factored in when choosing a cam. Specs will vary, but in general performance camshafts have higher lift to open the valves further, increasing airflow and power. Performance camshafts also typically have longer duration - the valves are open longer, which increases high RPM power. Longer duration is typically accompanied by increased overlap (when both intake and exhaust valves are open), which can enhance cylinder filling at high RPM, but can also result in less vacuum for power accessories at low RPM.
Lobe Separation Angle (LSA), the number of camshaft degrees between the centerlines of the intake and exhaust lobes, is another spec you'll encounter. In general, a camshaft with a tighter (smaller) LSA makes more torque at lower RPM and increases cylinder pressure; valve overlap is increased, with less idle vacuum and a rougher idle. A wider (larger) LSA reduces maximum torque but the power band is widened and peak torque occurs at a higher RPM. There is more vacuum at idle and idle quality is improved. A cam can also be advanced or retarded during installation to alter the RPM where peak power is delivered.
There are flat tappet and roller performance cams and the proper lifters much be used with each kind. Roller cams have much more aggressive ramp rates that would cause a flat tappet lifter to dig into the ramp. These ramp rates allow the valves to open faster and remain at high lift for most of the opening duration, which increases power. Roller cam and lifter kits are available to convert older flat tappet engines. Flat tappet cams should always be purchased in a kit that includes new lifters. As a rule, the entire valvetrain should be upgraded when a performance camshaft is installed, especially the valve springs. |