Mailbag: Camshaft Lobe Separation, Nitrous Oxide & How They Relate

Got questions?

We’ve got the answers—the Summit Racing tech department tackles your automotive-related conundrums. This week, we examine ideal camshaft lobe separation for nitrous applications.

D.M. Pitman, NJ

Q: Can you shed some light on camshafts made for nitrous engines? Why would they have a lobe separation of 112-114 degrees, versus 106-108 degrees for an otherwise identical cam?

A: Here’s the scoop on nitrous cams. To compensate for the additional fuel being used and the large amount of exhaust gases created in a nitrous-powered vehicle, nitrous-specific camshafts are designed with higher exhaust valve duration and lift. The opens the valves earlier and closes them later.

A cam’s lobe separation determines where and for how long peak torque occurs in an engine’s rpm range. On a tight lobe separation, like 106-108 degrees, the engine will build torque quickly and reach its peak early. Given that nitrous works best in the mid- to upper-rpm range, nitrous-powered engines need a wider lobe separation, like 112-114 degrees. With a nitrous-specific cam, peak torque will be spread out over a broader portion of the basic rpm range, with maximum power up top–where nitrous performs best. Hope that clears things up!