2011 BMW 135i N55 Stage 3

This BMW 135i N55, fitted with a high-flow turbocharger, upgraded intercooler, and VRSF downpipe, received a custom MHD tune optimized for tarmac racing. The calibration refines boost dynamics for smooth, progressive power delivery, with fuel and ignition maps tailored for peak efficiency under high load. Valvetronic and VANOS were optimized to enhance low end response and mid range torque for sharp corner exits while extending high RPM power beyond 6000 RPM for straights. Knock detection and thermal limits were adjusted to ensure reliability during extended track sessions.

The XHP Stage 3 transmission tune enhances the ZF 6HP gearbox, with increased line pressure for firm clutch engagement and reduced shift times for rapid gear changes. Torque converter lockup was recalibrated to minimize slip, ensuring precise power delivery under high-torque conditions.

Dyno Results:

The 33% power increase and 44% torque gain deliver a track-optimized powerband with daily drivability.