Which LSA for a....
Im no expert but thats pretty much how i understand it so far.
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You do not want a 114 lsa TV3 in a stock cube unless you are ready to rev to the moon. 111 will benefit the Auto powerband better but it will take some good tuning.
Also does anyone have a cam like this? a lot of cams have negative overlap.. every car out of the factory has negative overlap. Lots of turbo and FI cars have negative overlap.
If you are running a Forced Induction car, you want to keep overlap in the very low positive, zero, or even negative range.
Overlap is the amount of time in crankshaft degrees that both the exhaust and intake valves are open for a given cylinder. Overlap allows a cylinder to draw air from not just the intake manifold, but also the one in overlap. At low speeds, the cylinder drawing the air "chokes" on the exhaust drawn from the overlapped cylinder, hence why you hear a choppy idle. The car WANTS to die. At higher speed, the exhaust system has created enough air velocity to "suck" the exhaust air out of the cylinder in overlap, and the cylinder drawing from it will draw clean air from another intake runner. This is great in an NA situation. It's not so great for Forced Induction. The pressure inside the intake manifold, under boost, will blow it's pressure through the intake valve, and right out of the exhaust valve that is open during overlap. A little bit of overlap here CAN be good, as it blows some of the "dirty" air from the exhaust into the headers. This is also where backpressure comes in, but that's another story. Negative overlap here "seals" the intake stroke so that all of the boost pressure is going right into cylinder and nowhere else. Less overlap also provides more vacuum and a better idle.


