For almost a decade, we've been fine-tuning the performance of M60-powered BMWs, and our latest creation is a custom EPROM chip (dubbed the 7 speed shop circuit special) designed specifically for the M60B40 engine using the 404 DME. Having gone through various off-the-shelf performance chips, we found most offerings fell short of expectations—particularly on our M60B40 6-speed swapped BMW E23. Frustrated with the underwhelming results, we decided to take matters into our own hands.
At the heart of our new tune is the ECU map from the E34 540i 6-speed, an ideal starting point. We dug deep into the fuel and ignition tables, completely revising both the part-throttle and wide-open throttle maps to ensure smooth yet responsive power delivery across the rev range. Idle characteristics were also addressed for a refined, stable engine behavior even with a lightweight flywheel, and we removed the speed limiter—particularly beneficial for swap vehicles that no longer have a DME speed signal.
The results speak for themselves: with supporting modifications in place, our custom tune pushes the M60B40 to an impressive 315 horsepower—revitalizing the engine’s performance and making it feel more alive than ever before. This is a significant improvement over the factory setup, allowing owners to experience their M60-powered BMW in a whole new light. Whether you're enjoying the streets or hitting the track, this tune delivers a substantial boost to both drivability and power output, transforming any M60B40-equipped BMW into a true performance machine.
For those who demand precision, reliability, and performance from their BMWs, combining decades of experience and passion with years of tuning expertise, this tune is the ultimate upgrade for your V8 BMW. Our performance chip is available to purchase here- https://www.7speedshop.com/products/m60b40circuitspecial
