Daily Driving a 745hp BMW
We enthusiasts look at our beloved BMWs as truly the Ultimate Driving Machine straight from the factory. That said, is it possible to make them even more … Ultimate?
For many of us, myself included, tuning our modern turbo-engined BMWs is the next step to both higher performance and personalization.
First, when someone talks about "tuning" their car they are speaking about engine performance. If you are changing lights or dash behavior or other more software-style changes, that is usually called "coding." Tuning is using a software platform like Bootmod3 or MHD or others to update the actual tune your motor is using, with the goal of increasing horsepower, torque, and overall performance. It really can be as simple as plugging in a wireless OBD2 adaptor and connecting your phone and your car is ready for more power.
My first turbo BMW was an F32 435i with the impressive N55 motor, and I learned very quickly about its potential. Changing from naturally aspirated motors like previous generations, the new turbo-driven motors are easily upgraded for power. Unlike previous motors where eking out power is expensive and complicated, the new turbos can be modded by simply bumping up turbo pressure. Over the span of several years, I took the stock motor from 300 horsepower at the crank, to an impressive 440 (whp) horsepower at the rear wheels! The build was stable, reliable, and incredibly fun to drive.
The real journey though was started when in January 2021. I purchased a 2019 M2 Competition with the incredible S55 M motor. The car put up expected performance shortly after on a dyno baseline at 403whp and 466lb of torque. Yes it was a slight step back from the heavily modified 435i, but I also had an eye on the future and tuning this new platform. The S55 motor is incredibly well understood now by the modding and tuning community, with a vibrant ecosystem of upgrades and available tunes.
When we talk about tuning modern BMWs, let’s just address the elephant in the room and then move on: your warranty.
Yes, if you tune your BMW meaning you unlock the ECU and make changes, you should accept that your powertrain warranty is probably gone. BMW is now reportedly automatically scanning for this change when your car gets plugged into the computer. This is not the dealership’s fault or even their choice; they end up just carrying the message you may not want to hear. If you are already outside warranty than this is a non-issue but is a choice if you are still within that period.
The other controversial subject to cover is the infamous S55 crank hub problem. There is no lack of opinions on this issue, or even if it is a problem for the motor. I won’t try to decide for others, but knowing I was looking to do a big power build, it was the very first change I made to the car. Addressing any crank hub slippage issues for me just made sense as I knew I didn’t want to worry about it.
After the crank hub, I used the popular tool Bootmod3 to unlock my ECU and work through flashing to upgraded tunes. There are many "off-the-shelf" or OTS tunes available depending on the upgrades you already have installed. If you are looking for a quick and easy power upgrade on a stock motor, stage 1 style OTS tunes can be a great way to bump 20-50hp and walk away happy.
Tuning really can be a journey of "what’s next…" depending on your goals and its easy to start chasing the next upgrade. Coming off the experience of the 435i and upgrades I didn’t do there, I knew I wanted to take the M2 Competition even further. The goal was to move through the more typical stage 1, 2, and 3 tunes and transition into a big turbo upgraded custom tune. The only hard limit I set was staying within the capabilities of the stock engine block, even though ultimately the upgrades could push well beyond that.
With the most recent and final subsystem upgrades completed, the M2 Competition now puts down 745whp and 620lb of torque. The car remains very drivable at lower RPMs and speeds, with a truly mind-blowing ceiling at wide open throttle.
Not too shabby for an everyday daily driver!
Now, about snow tires...
| Check out more of Stefan's work on his YouTube channel: https://www.youtube.com/@BMWDIYGuy |