Why does my car lope at idle?

If an engine is not getting enough fuel (this is called “running lean”), due to fuel pressure (regulated by the fuel pump and regulator), restricted fuel injectors, a vacuum leak or really anything that throws off the fuel mixture going in to the engine, this can cause the surge.

Why do big cams sound 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.

Why do cammed cars sound choppy?

Generally its because the aftermarket camshaft (s) are lobed to change the power band of the engine. Valves may stay open longer, close quicker than the stock cam was designed for. This is why idle may sound “choppier” and run rough at idle.

Why do race engines lope?

A compression leak may come from a cylinder head gasket and cause the engine to lope sometimes. This usually happens because the engine has high mileage, or a particular failure, like overheating, caused the gasket to blow. To check for a leaking head gasket, do a cylinder compression test using a vacuum gauge.

What is considered a high duration camshaft?

A 280-degree-duration cam holds the valves open longer than a 260-degree-duration cam. Holding the valves open longer allows more air and fuel into the engine and also allows more to get out through the exhaust. Longer duration (higher number) improves top-end power but almost always sacrifices low-end torque.

What is a cam lobe?

Cams located on the camshaft that open and close the intake and exhaust valves in time with the motion of the piston. Cam lobes control the valve lift, and there is a direct relationship between the shape of the cam lobes and the way the engine performs in different speed ranges.

What is a Stage 3 camshaft?

The Stage 3 cam is designed to work with some larger valves, port work, and upgraded carburetor or EFI system. This cam starts moving the power band a little higher in the RPM range (2500-6000). This is the biggest cam we recommend for a street application. It is used commonly in the race and hot street applications.

Is camming your car illegal?

yes, unless it comes with a CARB certification number. Any modification is illegal (even just changing the mufflers) unless it’s certified by CARB.