NRW Design - S58 Gen2 Exhaust Cam Blocks - BMW G8X M2/M3/M4

For those making serious power with single-turbo setups or built engines running high boost, a common limiting factor becomes exhaust camshaft drift - often referred to as “cam walk.” This is something tuners routinely monitor, and once it starts occurring, it becomes a hard limit to safely dialing in more power.

To address this, the NRW Design Cam Blocks to help mechanically stabilize the exhaust camshaft, allowing tuners to safely and consistently calibrate high-output engines without the unpredictable behavior caused by cam movement.

While this issue is most commonly discussed on the S58, the same mechanical problem also applies to the B58. Although the B58 only runs a single HPFP versus the dual-pump setup on the S58, the fundamental load on the exhaust camshaft remains - and so does the risk of cam walk at higher power levels.

Exhaust Cam Load
On the S58, the exhaust camshaft drives two high-pressure fuel pumps. When engines are tuned with higher fuel demands, upgraded HPFPs, and often stiffer valve springs, the added mechanical load can exceed what the VANOS system can consistently control. This results in exhaust cam timing drift under high load or high RPM.

Fuel Pressure Instability
As cam timing becomes unstable, the HPFP drive events become inconsistent. This leads to fuel pressure oscillation or drop-off, which in turn causes inconsistent AFRs and forces the DME to intervene with timing reduction or throttle closures to protect the engine.

Erratic Engine Behavior
With both cam phasing and fuel pressure fluctuating, overall engine behavior becomes unpredictable. At elevated power levels - where precision and repeatability are critical -  this instability can limit performance and compromise long-term reliability.

How the NRW Design Cam Blocks Help
Our cam blocks provide mechanical stabilization of the exhaust camshaft, reducing its ability to walk under heavy load. This allows:

• More stable cam timing
• Consistent HPFP operation
• Stable fuel pressure
• Cleaner, more predictable tuning at high boost
• For serious builds, this is a supporting hardware solution that directly enables safer and more consistent tuning

Vehicles Supported
BMW G87 M2
BMW G8X M3/M4, including Competition
BMW F97/F98 X3M/X4M, including Competition