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

MERLINS RALLIART & EVOLUTION-X TUNING GUIDEHow do we log fuel trims? This is when you use evo4mad’s EvoScan.We start with the LTFT Mid. You must drive the car at a steady speed for at least 16minutes. Why? The fuel trims cycle approximately every 4 minutes. You will need tohave them cycle multiple times until they settle on a number in your log. 16minutes will allow your trims to cycle 4 times. That will give them ample time tosettle.Let us take my example above. We had the scaling at 552 for the PTE680ccinjectors. We cruised at a steady speed of 60mph / 100kph for 16 to 20 minutes.We found that the trims went way negative and hit -10%. So we pulled over andincremented the injector scaling from 552 to 573 (+3.5%). Flash the new numbersinto the ECU and then log again for another 16 minutes.The trims are still going negative but not as much as before. This time our trims hit-8%. We now know that we are on the right track. But we are nowhere near the±5% that we would like to hit. So we increment the injector scaling from 572 to597 (+4.2%). The new scaling is flashed into the ECU and another 16 minute logrecorded.The numbers in the log are now much better, with the LTFT Mid logged at -3%.Increment the injector scaling again to 609 (+1.9%). Flash the new numbers intothe ECU and then log again for another 16 minutes. The log reported a LTFT Mid of-1.86%. Increment the scaling again 622 (+2.1%). We have now dialed the LTFTMid to as close to zero as possible. This is because the data conversion formula willonly allow specific numbers to be entered. Pressing the [ key decrements the value,while the ] key increments the value. Thus for this example the only valid entriesare 552, 562, 573, 585, 597, 609, 622 and 636. In this case, the value 622 gavethe smallest trim error.Also note that the total of the increments, when added was 3.5 + 4.2 + 1.9 +2.1=12.7%. This is almost a perfect match for the initial trim error of -10%. Note alsothat the majority of tuners using these injectors finally settled on a scaling of 622!REV: 0.K merlin@three.com.au Page 93 of 134