[obiwanshinobi87]

Hi, I've got a 2016 340i with a JB4+Bluetooth Kit (latest firmware) and cold air intake, otherwise stock. I'm running Map 2 on 91 octane.

I've noticed in daily driving that when the car is in comfort mode and I floor it, the car actually kicks me into the back of the seat with its boost. When I switch to Sport mode, the steering and suspension tighten up as expected, but the motor seems to be a bit tamer. Definitely not as hard of an acceleration. It's completely the opposite of what I'd expect.

Anyone else notice this, or can explain why this might be?

[Terry @ BMS]

The sport vs. comfort mode only control the rate of power as a function of pedal input, not the peak power target. So at partial throttle they will differ, at full throttle match up, as we confirmed on the dyno.

[obiwanshinobi87]

Thanks Terry.

I've read that before, and assumed it to be the case until recently. I've noticed that I don't really even have to floor it to get a good kick out of the car in comfort mode, whereas the sport mode seems to be more linear in the power build up regardless of if I floor it or not.

Is this the car's ECU adapting to my driving habits, or does the JB4 completely override this aspect (I spend 99% driving in comfort)? Any chance you guys will offer an option to adjust steering feedback through the JB4 in the future?

[Terry @ BMS]

The JB4 maps based on various parameters, including pedal input, and factory boost target. But the best way to solve mysteries like this is with the JB4 logging feature. Record and evaluate runs from different modes to spot the technical differences.

On the steering I haven't look at it, but I don't think it's something we'd want to hijack for safety concerns.

[LessIsMore]

See if times are any different between comfort and sport using dragy or something.
Difference might just be all in your perception due to BMW trans tuning shift differences?

I don't believe any JB4 overrides the OEM 'learning' by either DME or TCU.

[Turboh]

Seat of the pants evaluation is tricky and depends on how you feel as well as numerous engine variables. I am finding that the only way to judge how fast you car is, is to log the runs as described in this thread, and then:

1. Import the logs in excel
2. Graph rpm vs time
3. Set the trend line for the resulting curve, it is linear
4. Ask excel to display the equation for the line and then look at the slope portion of that equation. It shows the rate of rpm change per unit time. This is directly related to your acceleration.
5. The higher the number, or slope, the higher the acceleration. Mine range from mid 40’s for map 4 to mid 50’s for all othe addive and absolute maps. Interestingly, high boost maps say 17 absolute on map 6 are not better than map 2. The difference is timing.....mainly.

I am finding that it helps me decide which map and map setting is best. It eliminated seat of the pants feelings. Much more objective.

Results so far have been that map2 is very good compared to all other absolute and additive maps. Timing is very important and boost numbers are deceptive.

[JorgeIII]

Originally Posted by Terry @ BMS

The sport vs. comfort mode only control the rate of power as a function of pedal input, not the peak power target. So at partial throttle they will differ, at full throttle match up, as we confirmed on the dyno.

Hello Terry. That might not be the case, at least for the B48M engine in the 320i.
Here you have some logs to compare at full throttle. Stock 320i map 4.

In comfort it starts with about 5 psi @ 2000rpm, climbs to 9-10 psi at 5000 rpm and cames back to 7 psi till red line. In sport it starts at 7 psi, climbs to 9-10 psi at 5000 and stays there till redline.

It's a different boost/rpm curve shape.



Jorge

[OzBMR]

I've found that absolutely stock standard B58 in M140i Comfort mode is 2 - 3 PSI lower peak boost than in Sport or Sport+, but timing advance is more in Comfort and less in Sport or Sport+ using 98 RON fuel (93 octane USA). I have done dozens of runs logging comparing all settings, generally in 3rd gear from around 2000 RPM and wide open throtle, manual shifting with ZF8, plus drag strip launches.

At the drag strip I found that Comfort mode gave ever so slightly the best 60 ft time, probably due to lower boost and less wheel spin and associated slip and/or traction control. On the street, in just 3rd gear pulls I got higher peak power and torque readings in Comfort in 3rd gear, which I put down to more timing, less boost and more grip down low.

Fastest time and best MPH at the drag strip has always been in Sport mode, probably due to having a higher grip surface and better mapping for drivetrain, gear change times etc.

Maybe the feeling of going faster when the OP floors it is a result of more/optimal traction from less boost?

[jbourne]

subscribed, i want to know more about this as well..