Hot Cams Builder Series camshafts
Hot Cams Builder Series camshafts are offered to provide additional choices to engine builders and race teams. This allows engine builders to maximize the power output of their engine package within the RPM range that they prefer. The following is a basic guide for engine builders to use when choosing cams for their engines. Builders should always try stage 1 or 2 cam sets first as they may work the best for your engine package.
Intake Cams will have the most noticeable effect on engine performance.
Intake Lift determines how much area is available for the incoming air/fuel mixture. Cams with lower lift will allow larger throttle opening amounts at lower RPM without the dreaded Bog (as will cam sets with a less amount of overlap). As intake lift increases, peak torque and mid-high RPM horsepower will increase as long as the other engine settings can sustain more intake volume.
Intake Duration determines how much time the engine has to take a breath of fresh air/fuel. In general, shorter duration will increase low RPM torque and longer duration will increase high RPM horsepower. Always choose the shortest duration possible for your desired power curve as long duration kills low RPM throttle response.
Intake centerline (lobe center) will move the torque curve up or down in the RPM range. Each crankshaft degree of change will move the torque peak by 100-200 RPM. Larger numbers after top dead center (ATDC) will produce higher RPM. Small amounts can be gained by “fine-tuning” the lobe center, but it is the last thing to worry about during testing. All Hot Cams are tested to determine the best centerline and it will be very close to optimal for all engine specs.
Exhaust Cams have a less noticeable effect on performance but they must be matched to the intake cam for optimal power output.
Exhaust Lift determines how much area is available for combustion waste to escape the engine. As exhaust lift increases from an inadequate amount, low RPM torque and peak torque will increase. Once the lift number is greater than the engine package requires, peak torque will drop and high RPM torque will increase slightly.
Exhaust Duration has the same effect as intake duration, but the results are more dramatic. The ranges of duration numbers that provide optimal performance for the engine package are quite narrow. Short duration helps low RPM torque and allows the engine to accept full throttle at low RPM and “chug” along. The correct duration for your engine package will provide the best peak torque and a balanced torque curve. Long duration will reduce low RPM and peak torque. The only benefit to long duration is that it allows the engine to carry out further past the horsepower peak, (although not necessarily making any more power).
Exhaust centerline (lobe center) will move the torque curve up or down in the RPM range. Although the result is not to the extent that is produced by the intake cam. Larger numbers before top dead center (BTDC) will produce higher RPM. Small amounts can be gained by “fine-tuning” the lobe center, but it is the last thing to worry about during testing. All Hot Cams are tested to determine the best centerline and it will be very close to optimal for all engine specs.