Odd fire 90,150,90,150,90,150 degree V6
Common denominator is 30 deg, which suggests 12 teeth on crank (also called 24+1 pattern with Tools/Play-trigger type c024)
Using per cylinder spark delay: Base setup/Cyl separated spark delay: see bench tested configs for
We continue to find other solutions and support more triggers (including Maserati).
Reftooth-based solution would be cleaner. WARNING: not yet passed testing
- alternatively 12-1 teeth on crank is another rational pattern (3,5,3,5,3,5 differences in reftooth because tooth width=30 degrees).
- or 36-1 (9,15,9,15,9,15 differences in reftooth because tooth width=10 degrees)
- or 60-2 (15,25,15,25,15,25 differences in reftooth because tooth width=6 deg) also makes sense.
As you see, that method is about
- the reftooth table.
- obviously the secondary trigger must be enabled as camsync
- also, enabling the odd-fire bit might be needed so the RPM does not fluctuate up/down according to 90/150 degree time, but measures every second event (240 degrees)
- maybe some cheating with the cyl number also needed to show correct RPM (the cyl number has no other effect currently)
However, different trigger pattern than listed above requires other tricks (or perhaps firmware mod).
Page needs to be cleaned up
- also we'll make index page to different odd fire engines (and some generic instructions).
- Generic information will come to this page, and specific to the Maserati biturbo goes to MembersPage/FPhil (started with very similar content)
Maserati factory trigger setup
[Maserati biturbo .wav] made by Phil.
- this has an uneven primtrig pattern 30,90,30,90,30,90, 30,90,30,90,30,90
- the only possible way to get 1.1.x working on this trigger is using divby2 with the "auditrigger" (because that is a pre-divider: divides before the pulses are considered giving 120,120,120,120,120,120 pattern). But than quite extreme per-cylinder ignition trimming (60 deg delay every 2nd cyl) is needed for the 90,150,90,150,90,150 result.
- as 1.1.x firmware tries to time from the last tooth and expects constant spacing between teeth (except at the missing tooth, or missing teeth). The InputTrigger/SubaruThirtySixMinusTwoMinusTwoMinusTwo and the uneven old-lancia/fiat and subaru has separate implementation in 1.1.x (while the maserati still does not have a dedicated handler)
- with 1.0.x the effective spark-tooth is "frozen" (not trying to time from the last possible tooth)
The solution to set 30 crankdegree teeth on the crank pulley was also recommended by Matthias on [Vems uk]
This is the reply I have posted
"The sensors are VR but it is not a big problem to make a Hall signal from them"
- indeed, there is also a VR=>HALL (LM1815 based) converter in DSUB9 housing now (with divider option for multitooth ABS sensors).
I can filter out one of the crank trigger or even I can divide the triggers by two to make 2 x (1cam trig +3 crank trig) each for one even fire 3 cylinders, for respectively the left bank and the right bank of the engine . But in this last case I need 2 GenBoards !!!
This is what Maserati has done for the late biturbos: 2 triggers + one ecu (ignition+injection) for each bank
The 30,90,30,90,30,90, 30,90,30,90,30,90 arranged according to ign events, trigger tooth marked bold:
- 30, 90, 30
- 90
- 30, 90, (next crankrot: ) 30
- 90
- 30, 90, 30,
- 90
The good news is that if firmware userspace "triggertooth" calculation can be tought about the uneven tooth-times (modifying the userspace easier than the interrupt timing code state machine), that might provide a simple 1.1.x solution.
- config:
- coil-type
- odd-fire bit enabled
- toothwidth=30 deg
- AND nr of tooth=6 (not 12 !)... this special value together with toothwidth=30 could mark this Maserati trigger for now.