Launch tuning

Hello,

I am curious what the ideal Cam positioning would be for launching a turbo car with VVT cams. We have a much larger turbo than stock. Launch mode usually consists of turning off traction control, putting the car in sport mode, making sure it is proper warmed up, then foot all the way to the floor with the brake and gas pedals then boost builds on the torque converter and release the brake.

Do we need to make adjustments to the cams with the bigger turbos since they spool slower? Do we need more timing retard in launch mode setting?

Christopher,

I generally start with the cam timing I developed on the dyno during the tuning process, but I'm used to RPM vs. Load based cam targeting. If your system runs a fixed cam position during launch, or perhaps is throttle based, then you may have to compromise a bit more. What do you have to work with?

Yes retarding ignition timing can help get the turbo going. Just be careful because once you get within a window, a small change can cause a great deal more turbine shaft speed.

Should both intake and exhaust cams be advanced?

In spool areas it's more common to benefit from intake advanced and exhaust retarded, but each application will differ and dyno time is key to dialing VVT in.

HPA has a great course on this: https://www.hpacademy.com/dashboard/courses/variable-cam-control-tuning/