Let me add that what constitutes an LSA being considered "wide" is relative to the rest of the camshaft specs, (especially the [email protected]
numbers). For instance: all of us tend to consider a "tight" LSA as being a 106, or a 108 LSA, but that mostly applies to street/strip camshafts with [email protected]
numbers in the 230-260 degree or even 270 degree range. But take a look at really big cams with lift specs in the .800+ or .900" lift range, and [email protected]
numbers in the 285-290+ degree range. You'll see that ALL of the cams that are that big have LSA numbers of 114, 116, and even 118. And even cams that big with a 118 LSA still create lots of valve overlap.
So in a certain sense,(at least as far as valve overlap is concerned anyway) cams with durations that are that long in essence can be considered having a "tight" LSA if it's 114, as opposed to a 118 LSA. Why is that you say? Because there's only so much valve overlap that can be designed into the cam before the engine just wouldn't run right at any RPM, and a camshaft with a [email protected]
duration with a 114 LSA will usually have as much valve overlap, (if not more) as a cam with a 260 [email protected]
with a 106 or 108 LSA will. Because with a lobe that has a 290 [email protected]
it's holding the valve open so long, much more valve overlap is unavoidable.
That's why you'll never see a cam with a 290+ [email protected]
with a 106 LSA or even a 108 LSA. It would be pretty close to physically impossible if you don't want the engine to run terrible at all RPM ranges, due to having waaaaay too much overlap between the intake opening and the exhast valve closing. You can only hold both the intake and the exhaust valves open simultaneously for so long. After a certain point, if you hold them both open for any longer, engine function begins to go south and performance suffers big time