spud 57 (2/10/2018)
Thanks Ted. I have now used an off set key. Much closer to Lunati specs. My concern is that it ran well at 102. Can you think of any reason it was set there? thanks.
Knowing what the ‘as ground’ lobe centers are would give an idea of the actual amount of advance or retard for the numbers you have posted which I would assume to be intake lobe centerline values. Also knowing the duration at both 0.020” and 0.050” along with the static compression ratio would be beneficial as that's a player in where you might want to install the camshaft. Being as this is in a supercharged street engine, it’s typically normal to have a camshaft ground lobe centers as small as 110° to retain some kind of low end torque when not in ‘boost’ mode. Because the compression ratio is typically lower in a supercharged engine, then a given amount of cam advance would be necessary to give a shot in the arm to the low end torque numbers. In a racing environment, the camshaft would be ground with upwards of 114° lobe centers or more to minimize blow through of the boost out the exhaust during the overlap cycle.
I have by design installed camshafts with as much as eight degrees advance in those applications that would benefit from that. It’s not unusual to have to move a camshaft as much as 4° one direction or the other to get a significant change in performance. Just doing 2° sometimes doesn’t pick up much change. I’ve found drag race engines that were responsive to retarding the camshaft to make more power. As a general rule, if having to advance the camshaft a bunch to improve the performance, the camshaft is too big. Likewise, if having to retard the camshaft to get a gain in performance, then the camshaft is too small.