What creates lope in a cam?
A long-duration cam will only take the engine so far in terms of additional top end power and rpm whenever the engine is rpm-limited by the flow capacity and velocity of flow in the cylinder head ports. Therefore, a long-duration cam will cause rough running at idle (lope) and a loss of low-rpm torque.
What makes a cam more choppy?
LSA (lobe separation angle) determines the choppiness, it has to do with the overlap of when both valves are open, as in when the exhaust valve is closing and the intake valve is opening to pull fresh fuel in on the intake stroke after pushing out the burnt fuel. Most GM cams come on a 112, 114 or 116 LSA.
What is a choppy idle?
A rough idling engine can be caused by spark plugs or spark plug wires. A plug that is damaged or installed incorrectly can result in fuel being burned at an inconsistent rate. If the damage is bad enough, you may also notice your engine running rough while driving.
What does LSA do to a cam?
Airflow and LSA A wider LSA moves intake- and exhaust-valve events farther apart and creates less overlap, which hurts intake-wave tuning. “When you’ve properly tuned a performance motor, you create high- and low-pressure waves in the intake and exhaust that help cylinder filling,” said Comp Cams’ Billy Godbold.
What does lobe separation do for a cam?
The primary function of narrow lobe separation is to impel urgent acceleration off the turns when the throttle is opened. A wider LSA, on the other hand, reduces valve overlap, offering better idle and cruising qualities.
Is idling bad for your engine?
Ten seconds of idling can burn more fuel than turning off and restarting the engine. Plus, excessive idling can damage your engine’s components, including spark plugs, cylinders and exhaust systems. Plus, driving – not idling – is the most effective way to warm up your engine anyway.
What does it mean if your car is loping?
We say an engine “lopes” or “surges” at idle when RPMs cycle unsteadily up and down. For example, a car may surge at idle between 600 and 1000 rpm.