Hot Rod - - The Evolution Continues -

Among the most dom­i­nant GEN4 fea­tures is its ca­pac­ity for mul­ti­ple map­ping. While there are per­haps hun­dreds of sce­nar­ios in which this is pos­si­ble, Meaney of­fered this by way of ex­pla­na­tion. Let’s say we have a tur­bocharged V8 with a four-speed trans­mis­sion; with a sin­gle map lim­ited to even some­thing as large as a 32x32 grid, there are still res­o­lu­tion lim­i­ta­tions when deal­ing with an en­gine that can run to 8,500 rpm and boost rang­ing from 10 to 40 psi.

The GEN4 of­fers the abil­ity to use a set of five maps per gear. Each set in­cludes the fuel, spark, lambda, in­di­vid­ual cylin­der spark (ICS), and in­di­vid­ual cylin­der fuel (ICF) cor­rec­tions. For turbo cars, an­other com­plete set of maps is used just to help bring the en­gine on boost when the three-step/tran­sbrake is en­abled.

Here’s how this works. In First gear, even with the po­ten­tial for 40 psi of boost, the car can only re­ally use 10 psi be­fore in­duc­ing tire spin. The ini­tial 24x24 map en­com­passes the 0- to 8,500-rpm range and the -15 to 40 psi load range. Once the car shifts into Sec­ond gear, Map 2 is en­abled. How­ever, its rpm range now could be from 6,000 to 8,500 and the boost range from 10 to 20 psi. By de­creas­ing the range of both the rpm and boost, we still have the 24 break points each, which will now pro­vide much higher res­o­lu­tion and con­trol. The 2,500-rpm span (6,000 to 8,500) is now di­vided into 24 col­umns and the 10 psi range (10 to 20 psi) into 24 rows. In Third gear, the boost now tra­verses be­tween 20 and 30 psi and will use Map 3. Once in Fourth gear, maps of­fer­ing con­trol be­tween 30 and 40 psi will use Map 4. In each gear, the tuner has the op­por­tu­nity to ad­just within the map with suf­fi­cient res­o­lu­tion so that over­lap­ping com­pro­mises are a thing of the past.

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