Can the BMW shop computer modify fuel/air ratio?

[ammolab]

Service mgr told me they added fuel by adjusting the "fuel trim" to make my bike smoother.

It was quite smooth already and I have a booster plug installed to fatten up the fuel a bit already.

Is he "BS'n" me? Am I mos likely running too rich now?

[Catchina]

Good question I'd like to know, so if the bike computer can do it why need a booster plug?

[Newportcycle]

I cannot speak directly to the BMW FI adjustment, but it would be a rare system that you cannot adjust fuel trim, necessary adjustment on any fuel injected engine. As to being to rich, if the adjustment was made "by ear" its hard to tell, fuel trim adjustments are best measured with an exhaust gas monitor to make sure the A/F ratio is the correct. I presume the plug was installed during the service inspection? As Don stepper motor fix pointed out there are other factors which contribute to a smooth running motor, but I'm sure your mechanic is well aware of that.

Service mgr told me they added fuel by adjusting the "fuel trim" to make my bike smoother.

It was quite smooth already and I have a booster plug installed to fatten up the fuel a bit already.

Is he "BS'n" me? Am I mos likely running too rich now?

[David R]

MAX BMW can re map your FI.

David

[Lost Rider]

Service mgr told me they added fuel by adjusting the "fuel trim" to make my bike smoother.

It was quite smooth already and I have a booster plug installed to fatten up the fuel a bit already.

Is he "BS'n" me? Am I mos likely running too rich now?

I would say yes, too rich now...

My bike spent a couple days on a Dyno at Bazzaz getting tuned, while they did richen it up in a few places in the RPM/throttle range they found it to be too rich in other places and leaned it out. It runs better now and gets much better gas milage to boot. 20-30 miles per tank improvement.
Based on this and the other 3 Bazzaz fuel controllers we have on our FI bikes, and having looked at the Bazzaz software while connected to the bikes while running to see the maps they made I'd say that by making a bike more rich across the board is just waisting gas and probably not helping but only in certain areas of the RPM/throttle range. If the booster plug uses a shotgun approach and does the same thing by just adding fuel across the board it also is waisting gas, maybe helping in some areas but certainly not in others based on what I've seen. But I have no intimate knowledge of what the booster plug actually does so thats just speculation. Seems like if it was a piggyback controller with realtime monitoring of TPS/RPM that connects into the bike in 4 different places to variably adjust the A/F mixure like the Bazzaz it wouldn't be so inexpensive though. I believe it's a one plug unit so it's probably not monitoring what's going on, and then having a dealer blindly add more fuel to the mixture via the OEM computer without knowing exactly what is happening with the A/F ratio, the chances of the bike having an optimal mixture throughout the throttle/rpm range are slim to none in my non-expert opinion.

Without having the bike on a dyno while analyzing the A/F ratio in the exhaust how could a dealer know where to richen a map, or lean it out?
I know that for dealers in California it is illegal for them to change a stock map due to emissions laws, BTDT with my Husaberg and Honda. A Bazzaz controller is sold here by stating that it is only approved for competition use on closed courses.

Be interesting to see what happens with your fuel milage after the supposed changed the dealer made. Did they adjust certain areas manually (blindly) or did they load a competition map or map from a different region, if such a thing exists for BMW's?
Are the sensors on the headers still connected? Bazzaz disconnected mine so I'm not sure if the computer will try to keep adjusting your bike if they are connected when it's not seeing what it thinks it should. I'm no expert with that sort of thing though.
Personally I would want to know what's going on in there if someone changed anything on my bike. Maybe inspecting your spark plugs will tell you if it's running too rich.... If you're happy with how it runs then who cares?

[ammolab]

I emailed the shop for clarification.....what was actually done at this service.

Sorry! All confused by bad info! The tech told the service manager....who told the service writer...who told me and the story got muddled.

I was told the tech added fuel trim. Truth is: the tech added BMW Fuel "treatment". Just a fuel additive, no Adjustment to the fuel/air ratio at all.

I did get 56mpg on the way to the shop (180 miles) and only 49mpg on the way home. I think the 18 mph wind following me there, and fighting me on the way home caused that.

Sorry for the misinformation that started this whole thing.

[Newportcycle]

I know that for dealers in California it is illegal for them to change a stock map due to emissions laws, BTDT with my Husaberg and Honda. A Bazzaz controller is sold here by stating that it is only approved for competition use on closed courses.

It's the same here, for a time the state was threatening instituting emissions testing as well, that, however has been defeated for the time being. For the last 14 years I've rode Triumph motorcycles, their fuel injection system was fully user adjustable with an aftermarket program "Tuneboy" very impressive piece of kit, not that the factory authorized such practice quite the contrary. You could download your existing fuel map and make adjustments all across the spectrum. They also had a unique interface which allowed realtime interface with a Dynojet and AF sensor. There were numerous folks who offered up tunes for review, some for sport, some for touring all with different attributes. The beauty of the system it would allow you, in two minutes, return the bike to fully stock trim for safety and emissions testing or dealer service calls. I agree with your assessment of the "Booster Plug" just tricks the stock map across the board, not a very effecient way of applying changes to the FI system.

[omg1010]

With the BMW shop computer the fuel mix/mapping cannot be altered! That can only be done using 3d party equipment (like power commander or other devices). The ECU itself can be reprogrammed only using a 3d party device/software called Rexxer. Contact: http://www.rexxer.eu/e_kontakt.cfm

However to do this extensive dynoing is essential. When I got my 12S rexxered it took the shop about 19 dyno runs and the same number of programming sequences until the best result was achieved.

Brgds
Oliver

[deilenberger]

As Oliver points out - it really can't be done by the dealer. Even if it could - the O2 sensor circuit, which is very fast and reactive on the R1200 series bikes would tune it back to whatever the stock mapping is. The only way to get around that is to fool the computer on what it's seeing from the O2 sensors. There are some systems like DynoJet's that take the O2 sensors out of circuit, which IMHO is a bad idea. Dunno how Bazzaz does it - but he may be doing a complete remap of the computer (which is against federal regs..)

The BoosterPlug only works at low throttle openings and idle by fooling the intake temperature sensor, and then only until the O2 sensors take over control. Since the O2 feedback loop is very active and fast to take over on the BMS-K bikes, it probably really does fairly little (and may well be adjusted out by the self-learning ability of the BMW-K.) There is an interesting discussion on how the BMS-K works on the oilhead forum of the MOA (even though they didn't use it - someone did some extensive testing of the BMS-K system to see what the effect and capabilities of the dual-O2 sensor based systems are. He came away quite impressed with what was going on.)

[sweatmark]

Sorry! All confused by bad info! The tech told the service manager....who told the service writer...who told me and the story got muddled...
I was told the tech added fuel trim. Truth is: the tech added BMW Fuel "treatment"...
Sorry for the misinformation that started this whole thing.

Ok, I forgive you, but only because of awe & respect for your M Coupe, which is what my 318ti wants to be when it grows up.

I doubt that any Motorrad service personnel would ever "tune" a BMW ECU unless a change in fuel map was part of a factory firmware upgrade.

There's a good topic in ADV (actually, a few topic threads) pertaining to air/fuel ratio tweaks during closed loop and open loop operation. I intend to experiment with a wide-band oxygen sensor (LC1) in the future, as addition to the open-loop device (IICE Air, Booster Plug) already installed on my Rockster. Slight enrichment of mixture is worth evaluating for bikes tuned lean by factory.

[deilenberger]

Ok, I forgive you, but only because of awe & respect for your M Coupe, which is what my 318ti wants to be when it grows up.

And my M-coupe gets no respect.. (It's an '01 titanium/silver over black)..

[Lost Rider]

For inquiring minds here's the map and what adjustments Bazzaz did to the oem map on my bike. This shows where they found the oem map to be rich or lean throughout the throttle position vs. rpm range.
The O2 sensors are disconnected.



It's probably a bit smoother, though I never really thought it ran too badly except when the valve needed some love or after filling up with chunky brown mexican gasolina.


I do get about 20 miles more per tank while on the highway now though and to me 20 miles could be a long ways to walk someday so I'm happy.







http://www.bazzaz.net/index.php/maps-research-database




http://www.bazzaz.net/z-notes/PDF/BMW_R1200R_07-11.pdf

[deilenberger]

Joe,

Are the O2 sensors left disconnected with the Bazzaz tune once they're done?

If so - the rich conditions of the stock map at certain RPMs doesn't surprise me at all.. the default map undoubtedly runs a bit rich so as to protect the cylinders against a lean condition (and holing a piston or something equally ugly..) I'd be interested in seeing their mixture readout in graph format vs the factory tune readout with the O2 sensors connected. To do it in a useful way, it's really necessary to run the mixture plot at set RPM steps (1,100 RPM, 1,200 RPM, 1,300 RPM, etc) not just as a full power run like Dynojet does.

Where are they measuring the mixture and what do they use? While some info is available from the factory O2 sensors, they are much more a GOOD/BAD output device indicating where stoichiometric mixture is achieved.. really would need to use a wide-band sensor to get good numbers. And doing it after the catalytic converter is pretty much useless - the cat does an effective job in cleaning up the exhaust, so mixture can't really be determined.

BTW - the PDF they give is a DynoJet output plot (they're somewhat distinctive), with a lot of smoothing applied, and it's a full throttle run (usually a 2nd gear roll-on, put it in 2nd gear and crank it open..) Be interesting to see without the smoothing. Looking at the plot (I have a bit of experience with Dynojet plots and BMWs), there is some improvement in the belly of the plot (where HP and torque cross over at about 5,500 RPM.) The differences at low and high RPM are almost within the margin of error of the Dynojet dyno, and I don't think they're significant. The reason to look at plots with less smoothing applied is that can indicate rich/lean mixtures by what appears to be noise in the plot. Lots of noise = a lean condition.

[Lost Rider]

Yes the sensors are disconnected now.
See what info is on their site or give them a call if you're motivated to find out more about about how their product works, sounds like you could shed more light on it with a little more info. They don't use a Dynojet, they build/sell their own dyno though.
Jason is the tuner who worked on my bike, I could see if they have a graph that's not smoothed if you want.


http://www.bazzaz.net


Here's an email from them:

Joe,
Jason mentioned you had a question on what AFR was used when mapping your bike. I mapped your BMW at 13.0 with gains down low, mid range, approx the same between mid and top end with minimal gains at the very top. The bike should have better fuel economy since the bike was quite rich up until the last 3000 rpms and it then begins to run approx at 13.0 which is where I found the best results at. The map select jumper can be found behind the left side fairings near the bottom of the tank. This should be quite easy to access once the left fairings are off the bike. Please let myself know if you have any further questions.

Best Regards,

Del Edlefsen
R&D Technician

15330 Fairfield Ranch Rd. Unit E
Chino Hills, CA 91709
909.597.8300 ext : 103

[omg1010]

As mentioned a complete remap can be done by using this Rexxer equipment. My R12S has received that treatment and the result was a much smoother engine and gain of 3 HP and 6 NM.

Brgds
Oliver

[deilenberger]

Joe,

I do like their dyno.. it's available with an eddy brake. What that means is they use a magnetic field to create resistance to turning the drum. The Dynojet design is what they sell as their base model - an inertial dyno. An inertial dyno works by measuring the rate of acceleration of a known mass (the drum) against it's inertia to not want to turn (Newtons law at work.) The eddy brake was traditionally how dynos were made (and probably are in the car industry).. (some dynos also used mechanical brakes, or even paddles in water to provide the resistance.)

The differences are - with an eddy dyno, you can provide a continuous resistance to turning at a set speed, with an inertial dyno you can only interpolate the power being produced by an accelerating power source (the bike's rear wheel.) The eddy brake allows them to tune at a given RPM, maintaining the RPM for a long as is needed to achieve their goal.

I do question disconnecting the O2 sensors. They are pretty vital to adjust the mixture as atmospheric pressure changes.

The problem with trying to retune with the simple switching O2 sensors the hexheads use is they have a very limited mixture range where they actually respond (right around 13.8 if I remember correctly..) so if you try to fool the engine by offsetting the O2 sensors still in circuit, they go off-line since they're out of the range they work in. That can be solved using wide-band O2 sensors (which is what a lot of supercharged and turbo charged car kits do.) Wide-band means exactly that - they respond over a much broader range of mixtures. It looks like Bazzaz offers a wide-band to racers who want to do on-the spot tuning: http://www.bazzaz.net/index.php/fuel-co ... elf-mapper - lifetime of the sensor to me means it isn't intended for a bike used for street riding (25,000 miles perhaps?)

Interesting stuff. I'm currently learning all about the O2 sensors our bikes use since I have a replacement one I installed a month or so ago start going bad (it was a used one, and I don't know the history of it before I got it).. It's quite obvious to me now when it starts to go.. I get some surge at low RPMs and the idle becomes lumpy. Amazon is supposed to have a new one here for me tomorrow (a Denso "universal" 4-wire, the stock ones are made by NTK which is a part of NGK..) Even with the dodgy O2 sensor (it seems to start working at RPM > 3,000) I managed a 49MPG average on a 1,600 mile ride to and from Asheville last week, that was with lots of 2nd-3rd gear switchbacks at high RPM.. (ie - fun)..

[Las]

MAX BMW is a dealer; and will re-map your ECU. I had it done. Better throttle response. Better than the Booster plug that affects low RPM's only. According to the Dyno, a few more horses; but that's not what I was looking for. Only downside is the cost.