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VVT Retrofit Tuning?
- Thread starter bradsm87
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monstar
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Sure you can build main HO spark to follow cam if cam phasing was finite along one fixed path only. However whether cam remains parked and amount of phase varies outside one load / RPM table.
Baro is a modifier for example, this 3rd dimension has three discrete tables of load / RPM phaser movement.
Combustion phasing vs cam phasing - spark needs to be applied to phaser movement else you end up with woefully retarded combustion (heat, economy, torque) or dangerously advanced (knock, economy, torque). The finer you try and dial in the tune the more this works against you so you end up not far off where you started.
e38 VVT OS uses the torque model for combustion phasing, on top of GenIV's VVE. GenV tuning is nearly exclusively via the torque model.
So yeah wiring into pinout and sensors / oil control valve solenoid did work flagging in non VVT OS tune same like flex sensor. Programming phaser movement in the tables is not rocket science either, but there are continuously variable conditions for movment so you can't simply build a static spark path overlaid to main HO LO tables.
Getting independent spark vs movement (programmable combustion phasing) requires more than enabling a checkbox.
Switch to EFIlive and I'll do you a deal to run through it with you blokes, really takes our two valve wedge lightyears ahead.
Baro is a modifier for example, this 3rd dimension has three discrete tables of load / RPM phaser movement.
Combustion phasing vs cam phasing - spark needs to be applied to phaser movement else you end up with woefully retarded combustion (heat, economy, torque) or dangerously advanced (knock, economy, torque). The finer you try and dial in the tune the more this works against you so you end up not far off where you started.
e38 VVT OS uses the torque model for combustion phasing, on top of GenIV's VVE. GenV tuning is nearly exclusively via the torque model.
So yeah wiring into pinout and sensors / oil control valve solenoid did work flagging in non VVT OS tune same like flex sensor. Programming phaser movement in the tables is not rocket science either, but there are continuously variable conditions for movment so you can't simply build a static spark path overlaid to main HO LO tables.
Getting independent spark vs movement (programmable combustion phasing) requires more than enabling a checkbox.
Switch to EFIlive and I'll do you a deal to run through it with you blokes, really takes our two valve wedge lightyears ahead.
Last edited:
monstar
Naturally as-pirated
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- Peugeot 207 GTi
As mentioned before there are software challenges to consider (before tackling hardware integration) - phaser movement Actual vs Commanded, and e38 VVT OS compatibility.
I'm not confident that the different oil pump, variable hydraulic pressure of LS3 vs the different 'normalised' AFM circuit designed for VVT delivers same type and scale of oil control. I think you could tune around that with some work but perhaps not with accuracy per commanded.
Compatibility - US auto trans VVT OS and the manual AU non VVT OS may not communicate with external modules same, underlying (hidden) parameters, calcs and tables are different for likes of Comms errors to transmission, speed control, ABS and FPCM because firmware or part is different.
I'm not confident that the different oil pump, variable hydraulic pressure of LS3 vs the different 'normalised' AFM circuit designed for VVT delivers same type and scale of oil control. I think you could tune around that with some work but perhaps not with accuracy per commanded.
Compatibility - US auto trans VVT OS and the manual AU non VVT OS may not communicate with external modules same, underlying (hidden) parameters, calcs and tables are different for likes of Comms errors to transmission, speed control, ABS and FPCM because firmware or part is different.
