Hello, I would love of we could do negative timing maps. I install many vems' on high compression turbo engines. Special in low rpm, or I the area where the cat makes good torque, it is sometimes needed to run fx -5 degrees in timing.
Many stock Volkswagen does this from factory..
Any good idea?
The authority window is 64 crankdeg (63.75 actually) if the trigger is set up to true degrees (not set to camdeg, or something: in that case upto 127.5 crankdeg if primtrig is fed from cam).
63 crankdeg ignmap authority should be enough for normal (or even extreme) ignition MAP (and the ALS, launch, knock, ... retard is applied later, the final ignadv window is 128=64+64 crankdeg).
- Triggertooth / "TDC after trigger" can be cheated if needed:
- eg. 0 can be actual -10 crankdeg (10 after TDC)
- 10 will be 0 (TDC)
- 19 will be 9 (typical cranking ignadv: 9 crankdeg before TDC)
- and 55 will be actual 45 crankdeg ignadv.
- in VT, hacking ini files is possible to make it appear in a non-standard way
- but not recommended, prolly not worths it (the work, and the risk of some unintended/unseen effect)