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Originally Posted by Dragoneye
I just saw this statement...what do you mean by "engine tuning"? i assume it's not just bolt 'n drive, huh?
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Ahh. Well, the way fule injection works, is that the computer is monitoring the amount of air that comes into the engine, most commonly via a sensor known as the MAF (Mass Air-Flow)...sometimes cars use MAP instead, but it's the same in principal. The computer is already programmed from the factory with equations and algorithms that compute the amount of fuel applied to each cycle of the fuel injectors by modifying the flow rate, pressure (sometimes), duty cycle (how long it sprays), etc of each injector.
The computer monitors that air sensor, PLUS the throttle level (via a sensor knows as the TPS..throttle-position sensor), PLUS the feedback from the circuit of O2 sensors (monitoring how much fuel was left in the burnt exhaust), PLUS engine temperature, PLUS knock sensor....there's more I'm sure that I'm leaving out...anyway, it takes ALL OF THIS information and adjusts the air/fuel mixture accordingly. The GM Factory programmed your run-of-the-mill LS2 (for example) to run N/A (naturally aspirated...no boost). So if you start FORCING more air into the mixture, without telling the computer about it, then you have a serious danger of not adding enough fuel to compensate for the extra air...and you will very quickly have yourself in a LEAN condition. This is why you really want a competent tuner to re-program your car's ECU (or aftermarket system) when making a major change like adding forced induction (turbo/super).
Contrary to what I thought before I started playing with turbos...having more AIR in the mix is more dangerous than more FUEL. The FUEL actually cools the mixture down, an engine running rich (overabundance of fuel in the mix) will be sluggish and boggy. The more fuel you remove (or air you add) the hotter the explosion will be, and more heat/explosions means more power. The trick is to get the mixture as LEAN as possible without damaging things...when you start pre-detonation/pinging you know you've gone past the point of making the most power safely and need to add more fuel back into the mix.
Sorry, I write novels...I just love this shit.
