Very interesting post on iRacing forums by Greg West explaining how to manage MGU-K modes. Read it below. You can join iRacing and supporting us using this link (don’t click remove on referral).
While we are hoping to release a full vehicle manual #soon, this quick guide should provide a basic overview of the MGU-K deploy modes.
MGU-K DEPLOY MODE
The Mercedes W12 Hybrid system can run in one of five modes to alter how much battery State of Charge (SoC) is present in the system at the end of the lap:
No Deploy – This mode will prevent the hybrid system from using any of the charge stored in the battery and run the car solely on the combustion engine. This engine mode is only available during Qualifying and Practice/Test sessions.
Qual – The Qual mode will deploy the most energy of all the hybrid system modes and attempt to supply as much power as possible to reach a faster lap time. This mode uses a large amount of stored energy and can potentially discharge the battery completely if enough energy is not stored before the start of the lap, and consecutive laps can also risk completely discharging the battery. This engine mode is only available during Qualifying and Practice/Test sessions.
Attack – The Attack mode will produce a similar result to the Qualifying engine mode but with a deploy program more similar to the Balanced engine mode. Where the Balanced mode will attempt to maximize power deployment without depleting the battery, Attack mode will deploy power without a SoC target at the end of the lap. This can be used to reduce lap times for overtaking or closing the gap to a car ahead, but can deplete the battery completely. This engine mode is only available during Practice and Race sessions.
Balanced – The Balanced mode will deploy as much energy as possible to produce fast lap times, but will also attempt to maintain SoC of around 80% at the end of each lap. This is the most common setting used for Race conditions, but will require a few laps. This engine mode is only available during Practice and Race sessions.
Build – The Build mode will attempt to quickly charge the hybrid system battery for situations where Attack Mode may become necessary, or in situations where the Battery is low. This mode will attempt to quickly charge the battery by cutting deployment earlier than Strat 3 on the straights, with the goal to reach 100% SoC as quickly as possible. This engine mode is only available during Practice and Race sessions.
While on track, the Power Unit system is limited to four deployment mode changes per lap. Once the limit has been reached, the system will remain in whichever mode was selected at the time until the car has crossed the start/finish line. For best results, refrain from making changes during the first couple of laps so the system can stabilize to the current race conditions and your driving style.
