Cam guru required
Discussion
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I'm not into cams as such and haven't done any back to back testing with them, because with cam in block engines it's just too much of an effort, but I was going to say that historically people have run a narrow lsa to improve the midrange but cams like that tend to fall off after peak power quickly. A wider lsa helps spread the power out over a wider rev band, but might ultimately make less peak midrange.
Also because of the nature of your install (centrifugal supercharger) you have an inlet port which is effectively seeing higher flows than normally aspirated with rising revs. On overlap this pushes some of the fresh charge straight through the exhaust port..
the upshot is that if you are chasing the numbers then i would definitely go with a wider lsa than you have now. If it were my engine and I was starting from a blank sheet regarding cams (you have a minority install, you're the only person i know with exactly that spec) I would go for something over 115deg lsa .. and to be honest I'd probably push for something like 120. Because you have a roller cam the manufacturer has presumably pushed for very rapid opening and closing actions (otherwise why use one?) so with a tight LSA you will have a lot of lift on overlap, so spreading the lsa would be surely the first priority ?
But as I say .. i'm not big into cams and typically use the accepted industry standard cams for normally aspirated engines .. centrifugal chargers is something i know little about, I'm just telling it as if i were building your engine.
Also because of the nature of your install (centrifugal supercharger) you have an inlet port which is effectively seeing higher flows than normally aspirated with rising revs. On overlap this pushes some of the fresh charge straight through the exhaust port..
the upshot is that if you are chasing the numbers then i would definitely go with a wider lsa than you have now. If it were my engine and I was starting from a blank sheet regarding cams (you have a minority install, you're the only person i know with exactly that spec) I would go for something over 115deg lsa .. and to be honest I'd probably push for something like 120. Because you have a roller cam the manufacturer has presumably pushed for very rapid opening and closing actions (otherwise why use one?) so with a tight LSA you will have a lot of lift on overlap, so spreading the lsa would be surely the first priority ?
But as I say .. i'm not big into cams and typically use the accepted industry standard cams for normally aspirated engines .. centrifugal chargers is something i know little about, I'm just telling it as if i were building your engine.
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