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

MERLINS RALLIART & EVOLUTION-X TUNING GUIDE5.06-IGNITION TUNING – ASSESSING KNOCKYou need to get a number of wide open throttle logs, where the engine was runthrough the gears and some part throttle logs where the engine was run up throughthe gears. When you have these, if any knock is showing, you need to make anassessment as to why the engine is exhibiting knock.Start by closely examining your log to see where the knock occurs and if the knockis random or repetitive and predictable. Check the relationship with gear-shiftevents, the engine will often show some degree of knock when shifting gears,especially as the boost level is raised. Frequently, when an engine starts knockingat a gear up-shift, it will carry-on knocking for a while. Confirm that other logsshow the engine pulling cleanly through the affected area if there is no gear shift.Vehicles with automatic transmissions can be particularly susceptible to shift knock,the SST equipped EvoX-MR and RALLIART are no exception.If you have DET-CANS, use them to help confirm suspected real detonation. Itshould be pointed out however that as the ECU aggressively fights to reducedetonation, you may only fleetingly hear the event. This can be a real problem inidentifying knock if there is a lot of other engine related noise. On the other hand,DET-CANS will allow you to easily identify noise from the hydraulic lifters or failedcrankshaft or piston rod bearings. Not so easy to determine is piston slap noisefrom forged pistons, which usually run higher clearances. Experienced tuners canusually pick this though.One of the best ways to identify real knock is using EvoScan to log KNOCKBASEand KNOCKFILTADC, see the graph shown. In that graph, you can see thatKNOCKBASE in yellow is relatively consistent, but KNOCK FILTADV is a seeminglymess of noise, except where it solidly spikes over the KNOCKBASE line. This clearspike is real knock. If you see the KNOCK FILTADC (knock voltage) constantlyhitting the KNOCKBASE line in a messy way, not clearly spiking through the line,then this is noise and can be tuned out by adjusting the KNOCK MULTIPLIER value.REV: 0.K merlin@three.com.au Page 50 of 134