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S85 Datalogging 101

10K views 35 replies 13 participants last post by  Texasgrego 
#1 · (Edited)
Hey fellas, been wanting to write up a little something about data logging to help some members get a better understanding about this.. Me and Randy have been data logging for a while now, and its been alot of fun and really helpful!

Data logging

What it is:

Data logging has been a normal practice for me for years, esp in my N54 335i days when I was modding and expanding tuning for Terry @ burger tuning, testing alpha and beta tunes.
Datalogging is important whether you are stock or modded. It gives you a great idea of how your car is running, if its running at its peak performance and gives you a great view of values that might surprise and interest you.. Feel like your car isnt feeling fast? Time for a datalog to check.. Numbers dont lie..

What to use to log:

First lets start with what to use to data log on these engines…

The easiest software/cable i found is the software and cable combo from BimmerSoftware.com | Welcome to BMWSW.com
You can also use Bavarian technic cable which is more expensive and complicated/advanced for logging but also comes with 3 vins, so it can be used on 3 cars.
Both will read fault codes as well.. But The BT software will also read errors in every module of the car.

What the data means:

Some of the most important values to log would be RPM, IGN, IAT’s B1/B2, lamba B1/B2, Fuel pressure, throttle, etc. the bmw logger data logs many many parameters by default so no worries.

RPM: self explanatory, you want this logged to show RPM’s.

IGN: This is an important value. Most data logging tools will usually only show 1 cylinder, but that’s acceptable data to give a general idea of how the engine is feeling. All cylinders IGN logging would be ideal!

Through the rev range, you don’t want to see your IGN take a dive, or have multiple drop outs ( sharp downward spikes), this would indicate pinging, misfire, detonation etc. Want a nice relatively smooth IGN curve. You also want to see that during WOT, esp high RPM’s, you are able to hit the ign targets for this engine, which would mean the car is performing at its peak. If you aren’t hitting the IGN targets or having timing dropouts, then it is time to figure out why by first checking for any codes then possibly bad gas, spark plugs/coils not up to the task aka are too old, as this S85 engine loves fresh plugs, hot/humid weather might play a factor, high IAT’s, etc.

IAT: Intake Air temperature, always a interesting value to log. Always fun to log while you are driving
(be careful and pay attention to the road! Only use when parked)
Get to see how the IAT's fluctuate while stopped, in traffic, on the highway, and during WOT runs.

The Lower the IAT or closer to ambient, the happier the engine runs, and more power you will get.. You will be able to hit IGN targets. Higher the IAT’s go, power begins to get lost, as does your IGN will begin to retard and not hit its targets. So of course, closer to ambient temps IAT are, the better it is for performance.

Lamba:
A figure to use to see if your engine is running lean or running rich.. Can be converted to get a AFR..

How to datalog:

When you want to get a log, a few things to note to make sure you get a clean log!

For performance reasons, most logs are at WOT. So when you hit the log or record button make sure it’s before you go WOT so it is easier to get to the data at WOT and get rid of the part throttle driving.

Traction control should be 100% disabled so there is no interference to effect the data.
Also use comfort suspension mode and a smooth road.
3rd gear or 4th gear is ideal as it puts a higher load and sustains RPM’s longer then first and second gear to get a better look at the data.

You want to start the pull WOT from around 2-3K RPM all the way to red line to get a full power band log, this way you get to see how the engines is behaving at every RPM up to red line. Like mentioned, choose 3rd gear or 4th gear depending on the road available, 3rd gear has been successful.

For example, 3rd gear, around 3K rpm, press record on the logging software on your laptop, then go WOT all the way to redline, then you can hit end and save on your logging software. You have captured a clean log!

Data logging like anything else gets easier to do and easier to understand what each parameter does, and where those parameters should be from experience, and practice.

EXTRAS:
Via the bmw logger software, there are some parameters that aren’t converted to the log, but you will have to play back your data log on the bmw logger software to see the data.

1.)Throttle angle for bank 1 and bank 2.. This would be the throttle bodies sensor for each bank. When your throttle pedal is at 100% you want both these banks to be at 100% and be at 100% throughout the entire WOT run, you don’t want to see any throttle closure in either bank and of course this helps make sure your pedal, and both throttle bodies banks are opening at 100%

2.) Fuel pressure.. The second fuel pump kicks in around 5,000 RPM (also load dependent) and both fuel pumps are at 100%, the max fuel pressure is set to 6 bar here, or around 87 psi.. So on your logs you would like to see at WOT and high RPM your fuel pressure is around 87 psi.



Here are some numbers I roughly put together to help everyone compare their logs and get an idea where their numbers should be at:
5K RPM
IGN= 36-37 Fuel pressure= 87ish psi Fuel pulse= 9-10 Vanos in= 90-100 Vanos out= 110-120 Lamb= 0.87-0.91
Pedal angle= 100% DKPB1 and DKPB2= 100%

7K RPM
IGN= 31-34 Fuel pressure= 87ish psi Fuel pulse= 11-12 Vanos in=105-112 Vanos out= 105-112 Lamb= 0.87-0.91
Pedal angle= 100% DKPB1 and DKPB2= 100%

Here is the S85 IGN targets: Remember these are ideal numbers and most of the time we wont even hit them, but you want to be in the ballpark..



Here is a log showing a clean IGN log, no drop outs, and hitting its target, you can see the line is nice and smooth.. The spike to the right at WOT is a shift, that is normal.



Always remember, everything needs to be taken into consideration when logging and looking at data.. Everything effects one another within this data.. Octane level, fuel quality, seal level, pressure, ambient temps, heatsoak, plug health, etc.

Here are a bunch of sample logs that have been takin out from bmw logger software via .CSV and uploaded on datazap from me and Randy..
Scroll your mouse over the graph to see data and numbers.

93 octane evolve tune
datazap.me | 5soko | Evolve tune/RPI exhaust.. 93 octane

91 octane evolve FBO
datazap.me | randywei | LTH Run 08/31/15 Sal's Stage3 91oct Tune

93 octane evolve FBO
datazap.me | randywei | 95oct, LTH, Mateen Old Tune

Here is a example of how datalogging can help at times.
This setup had a few installation errors, and as you can see the IAT's were very high and after a WOT, IAT's were not decreasing which isnt normal for this engine..
This member had some bad airflow to his intake and ducting.
datazap.me | 5soko | built 240

Lets talk dyno's!
Most guys here will hop on a dyno, do a few pulls, see the numbers and wonder/guess how or what happened..
Dyno operators get their money, and all is well..

Well, datalogging helps in so many ways.. First and foremost, you get to see data of each run, specifically temperatures! Coolant, oil, intake air temperatures especially all have an effect on power and consistent power..

So what do you want to look at on a dyno? Well our S85 loves air, so make sure your shop has some good air slapping the front end of the car.. Next start up your logging software and check those temps.. The most crucial being IAT's since this is where most users and shops fault..
The s85 hates hot air, so keeping an eye on iat's is a must on a dyno to make good power.. You want to get as close as possible to ambient temps as possible.. Then do a run, again next run let the car cool off, bringing the iats back down to where they were your first run.. You will see using datalogging that shutting off the car and letting it cool down will only heat soak the intake further as this sytem wants moving air..

Also checking and keeping an eye on the coolant temp and oil temps of course, iats being the more fluctuating of the three is why we focus more on it then the other two...
Ive seen guys dyno their cars with iats over doubling that of ambient temps! So datalogging gives you a great deal of info at the dyno to help us users get good results, consistent results and information to work with...

Here is a older thread by Sal @ Evolve showing what happens when iats get really hot on our s85's:
http://www.m5board.com/vbulletin/e6...ion/200376-effects-inlet-air-temperature.html


Hope this helps everyone get an idea of what data logging is about and to help begin data logging on their cars. Im no expert by any means and im sure there are alot smarter guys here on the topic. But this is a start :) Enjoy guys

As always big thanks to Randy (Randywei), The Evolve team, Imran, Mateen and Sal, for their great tunes, helping understand these engines and parameters.
 
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#2 · (Edited)
Great intro write-up, Senad! Datalogging has been quite fun for me and I sure have learned a lot. It's a good way to check then health of your engine. I was able to find a faulty tune by logging and seeing odd ignition timing! And as you mentioned, I noticed in built240's logs that his IATs increased when at WOT instead of decrease. Logging is great for trying to diagnose problems.

BMWLogger isn't the fanciest logger out there, it doesn't log every parameter, but it does capture majority of the critical values and is cheap and easy to use.

One thing to add. You mentioned you can calculate AFR from lambda, but you didn't mention how. For gasoline, the stoichiometric AFR is 14.7 - that's 14.7 parts of air to one part fuel. The stoichiometric AFR for each fuel type is different, but for our cars it will be 14.7. To figure out what one's AFR is from their logs, you just multiply your lambda value by 14.7. i.e. 0.89 * 14.7 = 13.083 AFR. AFR above 14.7 is considered lean and anything below 14.7 is considered rich. If at WOT you are running lean then you are in big trouble.

I know Evan datalogs his E61 all the time as he is always making tweaks to his car. He uses BMWLogger as well, amongst other logging programs.

Good stuff!!
 
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#5 ·
Anyone running BMWLogger on a Mac? Any issues? I know they support both Windows and Mac, I was just curious.
 
#6 ·
I am. The only thing I had to do (and I don't remember the exact reason why) is that I had to set the packet refresh count from default 3 to 0.

No problems other than that first one.
 
#8 · (Edited)
I'm playing around with a new datalogger people have been talking about - DashCommand. It's an iPhone app. Will give feedback soon after I get some datalogging in. From an initial look it has potential.


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#10 ·
Sounds promising esp since it can be used on the go :) More options the better for the whole community!

I'm not sure if it applies with our cars, but when I data logged with my WRX, it was important to not select too many parameters as some data could be lost. The tuner would always give me a short list of about 8 data points to select. I used RomRaider if that matters.


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Bimmerlogger is good with this as it auto chooses most of the parameters so you cant choose yourself what you want, it just logs it all, but works fast and no data loss.
 
#9 ·
I'm not sure if it applies with our cars, but when I data logged with my WRX, it was important to not select too many parameters as some data could be lost. The tuner would always give me a short list of about 8 data points to select. I used RomRaider if that matters.


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#13 ·
What an excellent tutorial!!! Even though I am now on the turbo-side of things-appreciate hearing about the V-10 and tuning. Just got my 2015 M5 back from the dealer and have to say I miss reading (and driving) and contributing to this forum. I hear there is a tune for the S85 that is twice as good as the standard? Is that true?:laugh
Thanks,

Bill
 
#18 · (Edited)
Can we datalog the knock count. Preferably by cylinder.

Thanks
Testo might be able to do it. I will check later.

UPDATE: Just checked and the MSS60 ECU provides only the adaption values for knock control. They are called "Adaptionwerte Klopfen auslesen" (read out knock adaptation value) and "Adaptionswerte Klopfreglung auslesen" (read out knock control values).

Worth a try and take a look at. What do you need it for?
 
#23 ·
My... What big boxes you have! :applause:


Now, whatta ya plug it in to? :frown


I don't need to sample data at the rate of a shuttle launch either,
a few thousand times a second should be more than sufficient lol

Something like the Vbox HD (many brands avail.), but with more than 8 CAN parameters
I like the idea of the memory card where you can take it out, data and video can overlayed for track use , and you can extract and manipulate on pc


Is there a good spot to plug in for a perm. hardwire, jcolley?

Maybe y'all can help with the Christmas list :2:
 
#31 ·
Like I said before on this forum: This software is poorly written. Which would be okay if the service was right and issues would be resolved. But not so much! I have been stumbling on stability issues and data corruption loss on export to csv files. I approached the author and I was literally blown off on two counts. A total jerk. Not even an attempt to understand my use case. The OBD interface driver is flaky, poorly written and covered up with a semi good looking non Windows standard user interface (but certainly not user friendly). I am done with it. 50 bucks wasted.

I have been using Testo. Although the user interface does not appear as 'shiny' as BMWlogger, it is actually good software and reliable. And free. Just a bit more work to get pretty graphs in Excel.
 
#33 · (Edited)
That is it. I forgot it default to more packerts
This software can't keep up with output.


I liked working with the BAV TECH. It was pro edition not vin locked the performance tech at my bolt on shop uses for BMW.
Tons and tons of live feed. He goes this things got more sensors than the shuttle lol

Might try that as wifey has 4.4 tt that's under warranty but can look in help others also
That's what I saw on your screenshot? I like comparing banks on the bars next to each other

WAY more fun than figuring out error codes.
thx
 
#35 ·
Haha yes bav tec works awesome.. I have a saved file somewhere that is used to log via bav tec the most important parameters.. Ill try to find it and post it..

Sorry..... just can't stand the BMWLogger dude.... LOL!
Haha i know.. The owner is rude as hell, i agree! You dont have Bavarian technic software do you? Pretty good stuff with a wide range of options for logging.. bmwlogger seems most simple for a wide range of users here on the board so why i pushed on it.. But bav tec works great if not even better as well but not as user friendly... Just really glad everyone has started logging no matter what is used! Really a great community
 
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