Quote:
Originally Posted by pokeybritches
After months of work, I’m happy to report that I’ve successfully swapped the stock MS45.0 ECU for MS45.1! Since I haven’t seen anyone else do this before, I’m going to call first 
The advantage of MS45.1 is that it uses wideband oxygen sensors for fuel control. MS45.0 is the standard ECU found in the 2003-2005 BMW Z4 3.0i and 2.5i, and it uses narrowband control. Narrowband sensors are all but worthless at full load because they can only tell the ECU that a mixture is lean or rich as compared to lambda 1.0… not *how* lean or rich. Wideband oxygen sensors can read the exact lambda of the mixture, allowing the ECU to provide precise fueling to meet the mapped targets. This is safer and will result in more power, especially if street tuning the engine with data logs.
On pump gas, lambda 1.0 = 14.7 AFR. Pump gas AFRs of 14.5 and 10.0 would read identically with a narrowband sensor. Even in a naturally aspirated application, this discrepancy in AFR can have a massive impact on how the car performs. In a forced induction application, the variance in AFR values could make the difference between an engine bogging, underperforming, and prematurely wearing components (rich) or catastrophically failing (lean).
The hardware conversion is easy once you get past the software challenges with the ECU, and I’m working to make the entire solution totally plug n play with a swap-in ECU. The only downside with the conversion is the loss of sport button functionality. This doesn’t make any difference to me personally since I have dialed in my preferred throttle mapping into comfort/normal mode. If you like the light-up button more than horsepower or long-term reliability, then this conversion is not for you. If you prioritize performance and robustness no matter the conditions, then I hope you find this solution as exciting as I do! |
Fantastic news Josh.
I'm in. Looking for the required parts now.
