Quote:
Originally Posted by DFW1LE
Right, tighter lsa moves torque to lower RPM, but with big duration, I believe it would shift torque curve in the other direction. Any how if its working well for you on the track that all that matters.
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So, in reality, a tighter LSA advances the exhaust valve events while leaving the intake events in the same place. Moving the exhaust events to open earlier and close earlier, in turn, will bring the peak torque down the scale. Lots of people think that LSA 115+3 would mean an LSA of 112. But that's not correct. the +X number will tell you exactly what your ICL (intake centerline) is. So if you ever had a cam that said LSA115+0 or had no advance, the ICL will be 115.
Its all a relation of air mass that you are trying to move. The higher rpm all motor engines we build typically have an LSA around 117 and the ICL is around 114-118. The reason is so the exhaust opens later. The goal is to use all of the combustion energy that you can before opening the valve. Blower cars like an even later opening event. Nitrous engines like an early exhaust valve open event. N/A falls in the middle of nitrous and blower. It doesn't have the violent fast flame that nitrous does and it doesn't have the big volume of air and fuel that forced induction has.