Merlins Ralliart and EvoX TUNING GUIDE Version K.pdf - EvoScan

MERLINS RALLIART & EVOLUTION-X TUNING GUIDE9.04-BOOST CONTROL - RPM/MPH CROSSOVERThe BOOST CONTROL RPM/MPH CROSSOVER parameter is a very important item ifyou wish to modify the stock boost control for two boost levels, based on the gearselection.When the rpm/mph is less than the crossover point, the ECU uses all the controltables labeled #1, ie BDEL#1 and WGDC#1. When the rpm/mph is more than thecrossover point BDEL#2 and WGDC#2 are used.Most examined ECUs have had the value set to 145rpm/mph, resulting in acrossover between 1 st and 2 nd gear. This parameter is fair game for tuning though,typically tuners will set it to crossover between 3 rd and 4 th gears.Figure 53:BOOST TUNING – tuned BOOST CONTROL RPM/MPH CROSSOVERThe table below shows the rpm/mph approximate values for GSR and MR variants.Thus, with a value of 105 rpm/mph, (as shown above) where the crossover is sethalfway between 2 nd and 3 rd gear, the ECU will use the second set of tables for 1 stand 2 nd gear. Instant gear based boost control!Table 4RPM per MPH GuideGEAR 2008 Evo X GSR 2008 Evo X MRGear rpm/mph Crossover Gear rpm/mph CrossoverRatioRatio1 st 2.857 175 1 st -2 nd = 145 3.655 194 1 st -2 nd = 1452 nd 1.950 119 2 nd -3 rd = 105 2.368 126 2 nd -3 rd = 1103 rd 1.444 88 3 rd -4 th = 75 1.754 93 3 rd -4 th = 804 th 1.096 67 4 th -5 th = 57 1.322 70 4 th -5 th = 625 th 0.761 47 1.008 54 5 th -6 th = 476th 0.775 41If you want to have all this as rpm/kph, then the factor in the scaling has to bechanged from 22.6 (mph) to 37.7 (kph).REV: 0.K merlin@three.com.au Page 79 of 134