Evo X / RA - Boost By Gear Patch

True boost-by-gear for the Evo X and Ralliart — independent Boost Target and Wastegate Duty maps for every gear. The factory Evo X ecu has significant limitations when it comes to boost control. There is a single crossover point which can be used for high/low gear boost control. When attempting to tune large turbo, high powered evo's, this results in compromise, particularly for 1st and 2nd gear to attempt to limit power. This patch adds real-time gear detection and gives every gear its own dedicated Boost Target and Wastegate Duty Cycle (WGDC) tables, so you can run soft, traction-friendly boost in 1st and 2nd and full boost up top.

What is boost by gear?

Boost by Gear is a tuning strategy used on high-power, high-boost cars to maintain better power delivery in the lower gears. This patch replaces the factory high/low gear targeting with fully independent Boost Target and WGDC tables — one set per gear (5MT: 5x, 6SST: 6x) — allowing fine control of power delivery at any speed. XSpec developed this patch while working on several high-powered 4B11 drag cars, where maintaining traction and power delivery in 1st and 2nd gear was critical. Previously, tuners had to rely on artificial throttle caps and compromise boost targets in the lower gears, resulting in wheel spin, bogging, and an inefficient launch.

Features

• True gear detection — the ECU continuously calculates the current gear from RPM and speed, with debounce logic so shifts register cleanly and consistently.
• Per-gear Boost Target + WGDC tables — fully editable in EcuFlash, using the same axes as the factory tables.
• Five complete map sets — a per-gear set for the stock/normal maps plus one for the first four alt-map slots (additional maps can be added on request). Map switching keeps working exactly as you're used to.
• Full Flex Fuel support — ethanol blending stays active, now blending between a per-gear pump tune (map set 0) and a per-gear E85 tune (map set 1). Boost-by-gear at any ethanol content.
• Full MethSafe support — when meth injection is armed, the ECU runs a dedicated per-gear meth tune (map set 1); if meth flow fails, it instantly falls back to your per-gear safe maps. Tephra's failsafe logic is untouched — same trip speed as stock MethSafe.
• Customisable crossover tables — dial in gear detection thresholds accurately to support aftermarket final drives or other wheel speed modifiers.
• Simple on/off switch — a single enable flag in EcuFlash. Switched off, the ECU behaves exactly like a standard TephraMOD V3 ROM, retaining the factory high/low gear correction.
• Datalogging ready — log the detected gear and gear-ratio value in EvoScan to verify and fine-tune detection thresholds.
• Compatible with the factory boost error correction.
• Compatible with the RAX Smart EC, Atmospheric Boost & SST Upshift Reduction patches (available here).

Compatibility

• Mitsubishi Lancer Evolution X / Ralliart, SST and Manual
• Works alongside all TephraMOD V3 map-switching modes: standard, alternate maps, MethSafe and Flex Fuel

What we provide

• Your current ROM patched with the boost-by-gear functionality, shipped disabled and toggled by a switch in the ROM.
• The XML definitions for your ROM, including all tables, safety gates and toggles.
• Log items which can be added to EvoScan to dial in your upshift & downshift thresholds.
• Continuous support and updates for future improvements to the patch at no additional cost.

Requirements

• A TephraMOD V3 base ROM already on the car — Normal Maps, ALT Maps, Flex Fuel and MethSafe supported.
• EcuFlash with a Tactrix Openport 2.0 cable
• EvoScan (or similar) for the one-time gear-detection calibration — a short datalog per gear is used to set the detection thresholds (instructions included)
• If you do not understand the boost control system on the Evo X - such as closed loop vs open loop, corrections, and the impact that increased load can have on boost control, pleae contact your tuner to dial in this patch. We recommend using psi-based boost control instad of load based for this patch implementation.
• You must send us your current ROM. Due to the ROM space required for the 12 additional tables, we cannot guarantee compatibility with other patches you may have installed (Rolling Antilag, Spark Cut, Secondary Fuel Pump Patch, other custom patches, etc). It is not safe to blindly overwrite 12kb+ of ROM space without appropriate precautions. There are also several hooks into factory functions which, if not correctly called, will brick your ECU.

Warnings

• Tune before you send it. The patch ships disabled and the seeded tables are safe starting points, not a tune. Verify boost behaviour gear-by-gear on a datalog or dyno before running full load.
• Modifying ECU firmware carries inherent risk. Intended for motorsport/off-road use; check your local regulations. Always keep a backup of your original ROM.