Depending on driving conditions, BMW offers 4 different modes: Eco Pro; Comfort; Sport; and Sport Plus.
These modes are changing the parameters of the gearbox, suspension, DTC system, and accelerator pedal. The current F32 is equipped with a manual gearbox, accordingly – one variable less.
What and how is changed?
Eco Pro – “surplus” consumers are switched off; the power of the AC is limited; the accelerator pedal is very unresponsive; the power/torque of the engine – very limited. The Start/Stop system is turned on (if it was turned off before). I’ll add right away – to drive in this mode is a true nightmare. BMW indicates that in this mode, you can save up to 10% of fuel. If we understand that the true saving is even less – no, it is definitely not even worth trying this mode.
Comfort – the zone of low and medium torque of the accelerator pedal is “stretched”. The steering wheel – light.
Sport – the steering wheel becomes much tighter; the accelerator pedal curve is much more aggressive. The Start/Stop system is switched off.
Sport Plus – additionally, the DTC system is turned off. If the DTC is turned on again, the car automatically switches to Sport mode. Also, the Cruise control is switched off (if it was turned on).
I was more interested – are the performance modes of the engine itself also changed?
What could be changed for such an engine than B58? VANOS is already optimized for performance in a current RPM range; the engine works only with Lambda around 1.0… Hmm… Performance of the tandem “turbocompressor/throttle/Valvetronic” could be changed! With the wastegate of a turbocompressor, the swifter turning of the turbine rotor during transition processes (swiftly increasing the required torque of the engine) could be forced; instead, with other tools – throttle and Valvetronic – the required amount of air would be supplied. In such a way, the max short response time of the engine would have been achieved.
A subjective “finding of the truth” did not really succeed. Of course, the engine has a better “pull” in the Sport mode because the curve of the accelerator pedal is changed. But Onboard torque and power tools on the NBT screen show that full power (240 kW) and torque (450+Nm) are reached in both modes.
The response of the engine (response time) changes? It is hard to evaluate because we speak about tenths of seconds for the engines with such power.
Of course, a perfect way, how to found the ruth – using dyno stand. But, if the requirements are more simple? Does the BMW use one or several management algorithms, which is also possible without a dyno? Unfortunately, the wastegate position can not be seen (nor true one, neither calculated); also, the calculated flow rate of the turbocompressor can not be seen. Have to think of something more cunning.
I decided to act in the following way: drive with turned-on cruise control and change the driving modes. At the same time – read the available Intake parameters in the Expert mode. I decided to use the cruise control to ensure that the speed; required torque/power would be invariable.
The first attempt with a comparingly low (but safe to traffic) speed of 60 .. 70 km/h fail – the speed turned out to be too low. Data indicated that the Charge pressure is 0 (relative), so – the turbocompressor did not show any signs of life by such low total power.
At a second attempt, I increased the speed to 100 km/h. It also is not a lot. Around 50 .. 60 Nm by 2100 RPM (in the 6th gear) means around 3 .. 4% of the engine’s total power. Accordingly, also exhaust gas flow is only 3 .. 4% from max. Without illusions – the turbocompressor will not be very “active” by such low gas flow to start it.
A first graph: Sport/Comfort/Eco Pro. 10 seconds are allocated for each mode. 45th to 75th second.
Legend of the graph. Note: Charging pressure and Intake pipe pressure are marked Bold.
It does not look that something would change fundamentally. Really a disappointment? But, if we take a more careful look – here:
Yes, really, the Intake pipe pressure has been changed! I zoomed in to see it better:
It’s clearly seen that in the 65th second when switching to the Eco Pro mode, the true (light green curve, bold) and calculated (light brown curve) pressure in the inlet manifold drops! Why so? Obviously, Valvetronic is used more actively. Valvetronic reduces the losses of pumping, allows to save fuel. So, BMW has created at least two engine performance modes. I did not start this test with a Sport Plus mode because the cruise control is automatically turned off in it. But now it is clear – it is worth it to continue the tests. The next test will be exactly for the 3 “usable” modes: Comfort/Sport/Sport Plus, but – now already without the use of the cruise control.
The second test. Here, the results (Y-axis is zoomed in to better see the results).
From 45th to 55th second I drive in Comfort mode. 55th to 65th second is the transition stage, in which I switch to Sport mode. I had to observe such a transition stage because of the “sensitivity” of the accelerator pedal change.
- to 75th second – Sport mode, 75th to 85th second – Sport Plus.
At this time, the difference between Comfort and Sport modes can be clearly seen! Differences between Sport and Sport Plus can not be seen, but it does not mean that there are none by higher powers.
So – BMW has created (at least) 3 sets of management maps for this engine! I wonder, do the “chippers” know this fact, not even talking about more complicated things – multidimensional maps of the injector adaptations, energetical model, etc.
Anyway, BMW with their offered Performance pack (which for large money: 2900 EUR – increases the torque to 500 Nm and power to 260 kW and provides for change of the exhaust, not only changes in the DME software) looks very “weak” on the basis on many offers from the same “chippers” for 10 times lower prices. 10% increase of throttle and torque for EUR 2900 against 25 .. 30% promised increase for 250 EUR…
I have reasonable suspicions that the first option really works when the alternative ones – give only problems…