Ok, guys and gals, maybe a dumb question or two, but I have searched....

2011 N18 with JB+ and the list of mods in my profile. I see 19.2 max (so far) as far as boost goes on my ScanGauge2. My questions are these:

Does the ScanGauge2 read actual boost, or what the ECU "thinks" it sees? Since it plugs into the OBD2 port, I would assume it's what the ECU thinks it sees.

How much does the JB+ "fool" the ECU?

How much is too much boost on a stock N18? Seeing 19.2 on my Scangauge2 may indicate that I am possibly pushing too much boost for the engine. Yes or no?

I have no issues thus far, and LOVE my JB+. But, at 55k, I am trying to make this little rocket last for at least another 100k.

Can anyone with a similar setup tell me what their higher-mileage results were?

Thanks in advance, and feel free to answer my questions one at a time, or chastise me for not getting a proper Tune. I know I need a Manic Tune, just not in the cards right now....

Cheers, Chris

 

I hit 24psi on a stock block, but with a larger turbo. Lots of people do 20psi, just make sure you run high octane in the car. 19 sounds a little high for a regular S Turbo

mQubed Motorsport, Manic Tuning Dealer

 

Thanks, Mario. I thought it sounded a bit high as well. But, no problems. I always run Union 76 91 octane, the best available at the pump here. I was told by the dealer mechanic that my car felt quicker than other stock cars he had driven. He even asked if I had modded anything, and at that point I had not. He was impressed with how well it performed. I guess I got a good one. LOL. Wednesday car, maybe? Or just a good builder? No matter, just happy to have a crisp car. I am looking forward to your Tune, but like I said, not just yet. The JB+ is set at 70%, and feels strong!

 

I had the JB+ and then upgraded to a Manic Tune. When you get your Manic Tune, you will wonder why you waited so long... The MCS is a whole new beast with a Manic Tune compared to a JB+

 

With the JB+ it has been recommended to stay at or below 18psi (S turbo) since you are using stock AFR maps, which are very lean for MPG. The manic tune adds more fuel so it is able to run more boost and timing, making more power safely. If you stay with the JB+ the limiting factor is octane, so people run race gas, E85 mixture, or meth injection to achieve that goal.

 

70% on the dial is a little high if 91 octane is the best you can get there. I have mine at 60-70% on BP or Shell 93 and I sometimes feel like I'm living on the edge. Be cautious if you want that MINI to last!

 

The scangauge is reading actual manifold pressure. It is the same boost reading that the car ECU is using. I would think that it would be fairly accurate.

 

Thanks, guys. I may just step the JB+ back to 50 or 60%. I am not sure that I understand how a JB+ works. I thought it lied to the ecm, understating boost, and therefore the ecm allows more boost. Is this anywhere near close? Also, if boost is added, leading to a lean condition, wouldn't the ecu compensate for this, based upon the input from the upstream oxygen sensor?

 

I had great success with my JB+ on my GP, but I wanted more (addict)

Here is a quick couple quotes from Terry Burger The DME targets load not boost. But, all the gauges we use read in boost as its an easier concept to get our heads around. Basically boost will change based on air density. The amount of information you'd need to truly understand the DME's internal operation is beyond what I have time or motivation to provide (sorry) but the DME is mapped on load (and torque) and translates that to boost as its final step in determine a boost set point at any given time. mQubed Motorsport, Manic Tuning Dealer

 

The JB+ is plugged into the mass air flow sensor so that is the parameter it alters and by doing so the car needs to increase boost to meet the targets.

 

For 91 octane it is recommended to dial the JB+ to 40-50%. The car does have a good knock sensor system, but you don't want to work it too hard. Part of what the JB+ does is trick the car to thinking it is operating at a higher elevation, which requires more boost to meet the load since air density is lower. As a whole, it moves the car further up the stock boost map (with associated fuel/timing). The lean condition is not because more boost is being added, but because that's how the stock maps are programmed (for MPG). Since the car is direct injection, it can get away with lean mixtures, even while under boost.

 

Should not be set to 70% unless you are running meth. Or unless it is one of the new versions that are California legal. The original ones are supposed to be set at 50%

 

Not sure if this is the correct thread for my posting, but this thread seems to be the most current and related to my query.

I recently bought a 2011 Countryman Cooper S and it runs well with no fault codes. I've datalogged it with the Torque app and I've come across something that puzzles me. I've been logging Speed, RPM, Boost, Air/Fuel Ratio, Airflow through MAF and Ignition Advance. Although the increase in speed and engine acceleration (i.e. RPM increase) appears to be linear, the plots for boost, and airflow through MAF are far from linear. To demonstrate my point, the graph below shows the plots of RPM and Boost during a 3rd gear acceleration.



I would've expected that the plot for boost would show some linear increase throughout the acceleration, or plateau, rather than rise/fall/rise/fall as is recorded. I know from datalogging other normally aspirated BMWs, that the ECU makes all manner of almost instant different changes to timing which produces very non-linear plots for this parameter, but I'm very surprised that the plot for boost is as variable as it is with my car. At the end of the day, the plot of acceleration is almost perfectly linear so it would seem that the ECU achieves consistent power increase by adjusting several different parameters to achieve a result.

My data points were all recorded at 1/10th second intervals, which is obviously faster than the polling rate of the ECU, as shown by the grouping of the plot points, but even if the data points were collected at 1/2 second intervals, it wouldn't change the basic shape of the plots. I've examined other plots of acceleration of my car and in other gears/speed and similar drops in boost seem to occur in mid-rev range.

Can anyone explain why boost on my car seems to drop in the rev range of peak torque? Have others seen similar plots with their N18 engines?

 

Someone can give a much smarter answer than me but here it goes. Boost is only what is needed to meet the calculated load and, as you know, is only one of many variables that is adjusted in real time and can vary by 2-3psi even under "identical conditions". You also have air temperature and altitude to consider.

I think boost would drop during the rev range of peak torque as not as much is needed to keep acceleration constant.

 

OK, still trying to figure out how a lean condition would not be read and compensated for. I get the fact that I may be overworking my knock sensor, but that deals with ignition timing, correct? So, if my upstream O2 sensor reads lean, the computer should compensate by adding fuel. I am sure to be missing something here. My point is this... no matter the lean/rich condition, nor the spark knock, the internal computer should be able to compensate, by either adding more fuel or cutting timing. It's not like I have taken parameters away, they still exist in the programming. There should be compensation. Right or wrong?

 

The factory maps run lean for mpg. The JB+ uses factory maps. This gives very little room for error as you artificially increase boost by cranking up the JB+. More boost does not necessarily mean more power if timing is retarded sufficiently to prevent knock/damage.

 

My AFR on my GP, with the JB+ and FBO was close to 13.0. Stage 3 and 4 Manic, my AFR's are around 11.3 and ignition is 5-6 degrees higher

mQubed Motorsport, Manic Tuning Dealer

 

Ultimate Stioichiometric ratio being 14:1, you guys are running WAY lean! LOL. I come from the musclecar world, so forgive my ignorance. It's just insane to me to see ratios like that! I guess I need to step into the real world.

 

Tis the magic of direct injection. We'd never be able to get away with it otherwise. The manic tunes run a little rich but better safe and leave some power on the table.