LSA Question
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Launching!
Joined: Jun 2002
Posts: 286
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From: Abilene, Tx
LSA Question Okay I'm still pretty new at this. So, my question is where exactly does the LSA come into play as in where the power starts or stops? (ie a 224/224 114 compared to a 224/224 112) Where and how exactly would be the start and stop of the powerband with each? Any help would be greatly appreciated! 
Re: LSA Question The best way to look at LSA is it changes the shape of the power curve. With a narrow LSA the curve will be more peaky with the high and low ends points closer together. As a result of this the idle will be rougher and the highest useable rpm will be lower as well as the peak power rpm. A cam can be designed with a longer duration to increase power output, but the engine will peak at a higher rpm, so most long duration cams are ground on a tight LSA to bring the peak down a little. The peak rpm point can quickly get out of range for the engine. But another way to bring the peak lower is to advance the cam (4 degrees is common.) The TR224 114 is designed this way. For cams that don't have advance designed in, you can install them advanced by using an adjustable timing set. The down side is a slight power loss. A cam ground on a 112 LSA should peak about 200 rpm lower than one on 114 degrees, but will idle slightly rougher and be harder to pass emissions due to idle missfire.
Cal 
