This minimizes pumping losses once the piston begins its upward movement on the exhaust stroke.
The term “pumping losses” describes negative work, or horsepower the engine must use to pump exhaust gas out of the cylinder.
The performance key is the huge torque gain that comes from a given amount of nitrous added to the engine.
For example, most nitrous companies using a 0.063-inch nitrous jet for a single-stage system will rate the package at 150 hp at 6,000 rpm.
If an engine is capable of making 400 lb-ft, add the squeeze and the twist jumps to 625 lb-ft, which is monstrous torque at that engine speed.
We talked with Comp Cams cam designer Billy Godbold, and his contention was that since nitrous already adds a ton of torque, why not improve the cam to make more horsepower as well?
Nitrous Cams`The buzz is all about whether those nitrous camshafts are worth the effort.
As overlap increases, it tends to improve midrange and top-end power by starting the intake process sooner.
As a result, the engine does not need the help of an earlier-opening intake valve (longer duration) to fill the cylinder. So we can delay the opening of the intake side using the wider angle, which also reduces overlap.
In addition, nitrous tends to create a very high initial cylinder pressure spike, which means the mixture burns more quickly.
The problem with lots of overlap when using nitrous is that the additional air and fuel is often lost since some of what is pushed into the cylinder immediately exits past the exhaust valve.
One way to prevent this situation is to widen the cam’s lobe-separation angle, which decreases the amount of overlap.