To appreciate the MED91 Multimap, one must first understand the internal mechanism it exploits: the vkKraQu variable. Within the MED9.1 binary software, there exists a variable named vkKraQu . This German abbreviation stands for "Variantenkriterium für Kraftstoffqualität," which translates to "Variant Coding of Fuel Quality". In its original factory function, this variable plays a role in helping the ECU adjust to different fuel qualities, for instance, by selecting slightly different ignition or fueling tables depending on whether it detects standard or premium fuel.
Many multimap patches also include additional functions like Launch Control (LC) No-Lift Shift (NLS) , and individual RPM limiters for each map. Implementation Guide 1. Preparation and Tools Binary File: You need the original file from your ECU. Patching Tool: Use a dedicated solution like the MED9.1-Multimap-Tool by EliasTuning or professional software like WinOLS Solutions Hex Editor/Ghidra:
The effect of switching the vkKraQu variable is not limited to a single parameter; it is far-reaching. When the MED9.1 Multimap Tool is applied, it causes the ECU to switch a comprehensive set of maps. The specific maps that are toggled between their 0_A and 1_A versions on the 1Q0907115C binary include critical tables responsible for: med91 multimap
Whether you are a track-day enthusiast or a daily driver wanting to switch between an aggressive race map and a fuel-efficient daily map at the push of a button, multimap tuning offers the ultimate in versatility.
When patched, parameters like LDRXN (Maximum specified engine load) and LDRXNZK (Specified engine load during knock) are cloned into indexed arrays: LDRXN_1 , LDRXN_2 , and LDRXN_3 . The active index is stored directly in the RAM, allowing the processor to swap tables instantly during active driving cycles. 🛠️ Step-by-Step Multimap Implementation To appreciate the MED91 Multimap, one must first
This real-time editability is the key that unlocks the multimap feature. The internal logic of the MED9.1 ECU uses the value of vkKraQu to decide which of its many internal tables to use. For example, if vkKraQu is set to "0", the ECU might use tables named LDRXN_0_A , KFZW_0_A , and so on. If it's set to "1", it will use the corresponding tables with a _1_A suffix instead, such as LDRXN_1_A and KFZW_1_A .
, with the rev counter needle flicking to indicate the selected map (e.g., 1000 RPM for Map 1, 2000 RPM for Map 2). Map Capacity : Most solutions support 3 to 4 distinct maps . Typical configurations include: : Standard performance (Stage 1/2) for daily use. : Low-power or "Valet/Anti-theft" mode. In its original factory function, this variable plays
Standard Stage 1, 2, or 3 optimization for everyday 95 or 98 RON fuel.