Clear this up for me please

[dabouncerx24]

Something about NA and FI setups. When your boosting and aiming for a high HP output, you need to "rebuild" your engine to support the high boost. But when your going NA and also aiming for a high HP output, once again your "rebuilding" your engine so the motor itself can produce the power. Whats the difference?

[IALuder]

the amount of power you push threw the motor.

[pdiggitydogg]

Its not really so much so the engine can produce power (minus cams and dome pistons). Rebuilds are done to ensure that the engine is in top shape and, with better parts, it can support the power without blowing up.

If youre asking why rebuild when going from one to the other, most NA setups are high compression, most boosted setups are low compression.

[thermal]

Building NA and FI motors are not exactly alike. The process of installing parts and component might be similar to some extent but the parts being used are different. You aim for a linear power for both, but NA cars have the advantage. As an example, If you compare the pistons that you typically use for both build-ups, you'll notice that NA cars have more angle on the piston tops. This is to allow expanding gases to exit the combustion chamber sooner and at the same time introduce fresh air.

On boosted application, you'd want a more flat surface pistons to allow more volume or increase the area of combustion through FI.

There are more variable to this. I've never built an N/A motor but I have a few friends who have. To me, it is actually a lot more complicated cuz the geometry has to be carefully calculated. I'm not saying that FI applications is any different. But when building N/A motors for street or weekend warrior purposes, you have to focus on everything such as drivetrain, valve train, head work, compression, rod stroke, blah blah blah... whereas FI, your main focus is to first make power.

Check this out: A 250whp NA vs 250whp FI is totally different. Providing that this is installed on the same car, I can guarantee that the NA 250whp will spank the crap out of a 250whp FI... hands down. I saw a 410whp NA hatcback ran only 12.5 while a 240whp NA ran 12.00.