Disabling VVT on DOHC - safe?

[Roland_Price]

Hi, everyone

I want to disable VVT (at least temporarily) on my 2016 v6 Camaro with LGX to tune base VE table properly. Is there any risk of setting the enable temps to -40C for intake/exhaust in Editor? In this case the system will be disabled (angles for both cams will be 0)? Is there a risk doing it on DOHC setup?

Also - is advancing +X or -X on these? And is it + or - for both intake and exhaust? Just wanna double check that I got these right

Thank you

[CYN_CRVR]

No risk; I did it by zero-ing the Desired Angle and WOT Desired Angle tables.

[KillboyPowerhead]

Not sure if the LGX works like the later LFX ECU (E39A), but if it does then the intake cam can only advance, so 0 is home position and numbers above 0 is that many degrees advance; the exhaust can only retard, so 0 is home and above 0 is that many degrees retard.

As CYN_CRVR said, if you have WOT tables and Low/Med/High Baro tables you could just 0 those to keep the cams at 0.

[Roland_Price]

No risk; I did it by zero-ing the Desired Angle and WOT Desired Angle tables.

Thanks. I've tried it and the loss of power is quite significant, I'll be digging more into this

[Roland_Price]

Not sure if the LGX works like the later LFX ECU (E39A), but if it does then the intake cam can only advance, so 0 is home position and numbers above 0 is that many degrees advance; the exhaust can only retard, so 0 is home and above 0 is that many degrees retard.

As CYN_CRVR said, if you have WOT tables and Low/Med/High Baro tables you could just 0 those to keep the cams at 0.

Thanks for weighing in on this. The VVT on LGX is capable of advancing and retarding, that's what got me confused a bit, still figuring it out

[CYN_CRVR]

Thanks for weighing in on this. The VVT on LGX is capable of advancing and retarding, that's what got me confused a bit, still figuring it out

I think positive cam angles are retard for both intake and exhaust.

Btw, do your logged intake angles properly reflect what you would expect them to be from the desired tables? My logged values for ICA were originally showing as (true angle + 100) instead of negative values. I submitted a ticket recently though, and HPT support fixed it. I have a 2023, so this issue might not have affected you.

[Roland_Price]

I think positive cam angles are retard for both intake and exhaust.

Btw, do your logged intake angles properly reflect what you would expect them to be from the desired tables? My logged values for ICA were originally showing as (true angle + 100) instead of negative values. I submitted a ticket recently though, and HPT support fixed it. I have a 2023, so this issue might not have affected you.

This indeed affects me - I have the same display of the intake cam, but the exhaust one is correct. Did HP fix it with the scanner update?

[CYN_CRVR]

This indeed affects me - I have the same display of the intake cam, but the exhaust one is correct. Did HP fix it with the scanner update?

Yes - update to the most recent Beta version of VCM Suite. If your intake cam angles are still wonky after that, then you should submit a new ticket with support (and you can reference ticket #445971, which is the one where they fixed it for me).

[Roland_Price]

Yes - update to the most recent Beta version of VCM Suite. If your intake cam angles are still wonky after that, then you should submit a new ticket with support (and you can reference ticket #445971, which is the one where they fixed it for me).

Thanks, will do

[Roland_Price]

Yes - update to the most recent Beta version of VCM Suite. If your intake cam angles are still wonky after that, then you should submit a new ticket with support (and you can reference ticket #445971, which is the one where they fixed it for me).

The latest beta fixed it for me as well, thanks. By the way - did you log your torque/HP losses after disabling VVT? It's a real PITA to tune VVT, but maybe it's still worth it?

[CYN_CRVR]

By the way - did you log your torque/HP losses after disabling VVT?

No... what would that accomplish?

[Roland_Price]

No... what would that accomplish?

I mean the delta between torque/HP with VVT enabled and disabled