What is a 2 or 3 bar tune?
2 and 3 bar tunes are actually special operating systems that are speed density and designed for higher horsepower boosted applications which will max out the MAF. These operating systems require the corresponding 2 or 3 bar MAP sensor and allow the PCM to “see” boost (the stock PCM is blind to MAP levels that result from boost) and adjust fueling accordingly. This is particularly important for turbo charged applications which can make boost in many different RPM ranges based on engine load, unlike superchargers whose boost is physically tied to rising engine RPMs.
