What is a durametric Cable:
A Durametric Cable is the cable Porsche uses to interface with the cars computer. With this cable you can check & clear fault codes, data log the car, reset the service indicator, view over-revs on a car and much more. For this thread we’re interested in the datalogging portion. See their FAQ page for more info: http://www.durametric.com/faq.aspx
Where do I get a durametric Cable:
From the manufacture is your best bet. http://www.durametric.com/buyus.aspx
They sell a “enthusiast kit” which lowest cost vs their professional kit. In it they have an option 1 & option 2.
-Option 1 is the absolute cheapest, but only allows it to work on a single car (they are locked to a VIN as soon as used).
-Option 2 allows for it to be used on 3 cars for slight price increase. This is usually the most common purchase, and is an easy item to sell on the forums later to recoup your initial investment since it still has 2 available vins left.
What do I need to run the Durametric Data Logging software and where do I get it?
The software can be downloaded from their website at no cost. However it will need an official Durametric Cable in order to be used. If you’re cable was not made in the past couple of years, it may not work with the most current software, but will still be usable with older versions of the software.
The software requires a PC to be run. However it will work in Parrallels and VMware. I use Parallels with a windows server 2008 framework installed to do all my logging and I have not had an issue with Durametric or Ross-Tech’s cable for VAG cars.
Lets get Started!
Now that you’ve got the cable, program installed, and in your car, the following will walk you through how to log. FYI, the car has to at least be in the accessory position for Durametrics to work. If you’re doing a data log, I prefer to wait to hook up the cable and program until after I’m at my logging location and the car is still running.
Step 1
Plug your cable into the OBD port and your computer’s USB Port.
Step 2
When you first open the program, this is what you will see.
Step 7
When you’re ready, Click Start. Ideally this would be moments before you’re 3rd gear log. It’s going to start logging many data points very quickly, so you don’t want to wait too long or your log will be buried under a multitude of data.
1)
You want a very smooth road with a minimal grade to it. It’s best to find a location you can use over and over so you can more accurately compare your logs as you change hardware/tune/gas/etc.
2)
Ideally you want a passenger to do the computer work for you. Either way, you want to setup the parameters for your log prior to getting to your logging location as it may take a minute or two to select everything.
If you don’t have a passenger, you can click start much earlier prior to you log and then click stop afterwards and just edit out the extra data.
3)
You want to do a 3rd gear pull, starting from below 2000 RPM to redline (kinda like dyno runs, but on the street). The idea is that when ready at ~1800RPM, you will click start on your log, depress the throttle fully, and take the car to redline without shifting or letting off the gas.
It’s ideal to shift to another gear (5th or 6th) while you brake to slow down, so that you keep oil pressure up
4)
I prefer to save each run/log as it’s own file rather than try to do multiple runs on one file
5)
When you get back home make sure to make a txt file with the Car’s condition (amount of gas, type of gas, hardware changes, passenger, etc) Weather (temp/barometric pressure/relative humidity/dew-point/elevation) and I like to not my roads beginning elevation and ending elevation (can be found via google maps. To simplify the weather, I simply calculate the DA (density altitude) and put it with the run as well as the temp.
A month from now, much less a year from now, it’ll be much more useful to compare when you look back if you save this data with it
6)
I prefer to copy all the individual spreadsheets into one workbook with individual worksheets. This makes it easier to share and reference later.
Then make one folder with the date or reference and put all the files into one folder. To clean things up even more, I compress the multiple data logs into one zipped file inside the folder and delete the individual files. This way you end up with a folder that has: combined log, conditions, zipped individual logs
Quick Tips
-F6 is the start/stop toggle button. This can be used instead of clicking the button which can help multitask. However, be careful not to stop a log when you think you are in fact starting it.
-Shutting off the “Graph Function” and selecting “digital display only” can help reduce CPU workload, help battery life, and help overall log accuracy.
-You can also adjust the refresh rate to create more, or less, data points as well.
[u][b]How do I know what parameters to Log?
Well, here are some suggested parameter to use.[/b][/u]
Some basic suggested parameters are:
RPM
LOAD
IGNITION ANGLE
OXYGEN SENSING BANK 1
ADAPTION RANGE 2 FRA BANK 1
OXYGEN SENSING ACTUAL LAMBDA VALUE BANK 1
OXYGEN SENSING BANK 2
ADAPTION RANGE 2 FRA BANK 2
OXYGEN SENSING ACTUAL LAMBDA VALUE BANK 2
BOOST PRESSURE OF SENSOR
To look at the Injector Duty Cycle Add: INJECTOR TIME
To look at the IC cooling efficiency Add: IAT
To look at the MAF readings, Add: Hot Film MAF, and/or Mass Air Flow
To look at Boost Control or Knock, use the following:
RPM
Engine load
Ignition angle
Mass air flow
Actual value throttle
Oxygen sensing bank 1 Lambda Value
Lambda setpoint B1
Boost pressure of sensor
Setpoint boost pressure
Boost pressure control P/D factor
Corr. factor for BPC with charge air temp.
Corr. factor for BPC with knock control
Using the latter set of parameters, we can use these values to see the duty cycle of the N75 valve, the boost setpoints, etc. This will tell you what the boost control is doing through the RPM range.
The preset version of each of these can be downloaded via dropbox, or as an attachment to the thread. Here is the dropbox link for preset logging recall file
Okay, I did all the work, I have piles of Data,
but what do I do with it and how do I understand it?
Alright, here’s where the computer editing / geek side comes out. I’ve made a spreadsheet through excel that you can use to view the formulas and what each parameter is used for, or how to convert it to a more usable measurement.
First, you’ll most likely notice a small green triangle in the corner portion of the box for a majority of the cells. You can highlight all of these and then click the small error box that pop up and select “convert to number”. This is where the datapoints of the .csv file were saved as txt, but excel recognized them as numbers, but needs your confirmation before using them as such.
The formulas spreadsheet can be downloaded at the same dropbox link here or via the thread attachment.
This has been debated some. I’ve found with the newest version Durametric program that it can log up to ~10 points at once decently well. (this is also somewhat computer dependent as well) The less points used, the more accurate most likely, however, you want to see how the different points interacting together. Logging only one or two parameters at a time isn’t an accurate example if used to compare across logs as they didn’t happen at the same time.
What gear to use? 3rd vs 4th gear. Dynos usually use 4th
We use 3rd gear as you can get almost equally valuable reading in 3rd with a much greater ease of attaining the log due to speeds required, distance covered, and quality of road needed. It is true, that we are basically wanting to look at the motor under load, and 4th gear offers a greater span of data with load on the engine and greater load sooner, but the comparable numbers are equal enough that there is little reason to use 4th. Therefor 3rd gear is more than fine.
Also, dynos typically use 4th gear as it is typically closer to a 1:1 ratio for converting power output to hp, which isn’t the direct goal of datalogging. Starting to compare to dynos opens up a whole box of issues, so lets ignore the idea of dynos vs datalogging.
Timing, and comparing timing from one car to the next:
Timing Advance. Timing is logged via “Ignition Angle”. It is also referred to as being “Advanced” or “retarded” depending on the shift.
[QUOTE=MARKSKI@911tuning;2897593]timing numbers will never be the same across the board… especially on different set ups… some run more timing less boost meanwhile others run more boost less timing…
[/quote]
For general knowledge to help understand how timing is used in our car and how it is used, the following is a brief explanation: The timing is inversely proportional to the load. So, as the load drops off dramatically due to the cams not retarding on a 996tt, the timing can go up to compensate and help the power out.
Boost Set Point vs Boost Pressure
Boost set point is the ecu requested boost pressure. Whereas the boost pressure the sensor’s reading.
Also, the stock boost gauge on the dash maxes out at 1.54 bar.
I want to log my MAF. What can I use?
Mass Air Flow (HFM)
Mass Air Flow (KG/H)
Hot Film MAF
The first two are a measurement of volume of air, the third is the voltage the MAF measures. The little know fact is that when the stock maf hits 5v, it is pegged to it’s maximum reading. This occurs at varying power levels, but I’ve see this is right near the maximum power of a flashed car with exhaust, and on a k16hybrid car is pegged out by 4500 rpm. The options are switching to a MAF that can read higher and tune for such, tune for a mafless car, or use a tune that utilizes the maf up to that point, and then acts as a semi-mafless car beyond it’s reading capacity. See this thread for more information diagnosing a bad maf:
What about AFR
The quick and simply calculation typically used is 14.7 x O2 Lambda
However, this is a very interesting and valid point
[QUOTE=rix;3498685]Something to keep in mind is the type of fuel you are running. In Texas anyway (and I suspect in a lot of places) 93 octane fuel is actually an E10 (10% ethanol, 90% gasoline) blend.
The wideband sensor does not determine what percentage of the fuel is alcohol, it measures the amount of oxygen present and delivers a lambda number.
1.0 lambda on gasoline = 14.68
1.0 lambda on E10 = 14.13
1.0 lambda on E85 = 9.85
If the fuel you are using is an E10 blend you will normally see a small notice on the pump that states that the fuel you are using may contain up to 10% ethanol by volume. Read this to mean that it DOES contain 10% ethanol, and you are running E10 as opposed to pure gasoline.
My Turbo (stock except for Europipe/BMC filter) seems to run about .84 - .86 lambda through the power band, getting richer towards the top.
The formula for this is simple;
(Stoich)x(Lambda)=AFR
E10 AFR at .86 lambda
(14.13)(0.86)=12.15 AFR
E10 AFR at .84 lambda
(14.13)(0.84)=11.86 AFR
Gasoline AFR at .86 lambda
(14.7)(0.86)=12.6 AFR
Gasoline AFR at .84 lambda
(14.68)(.84)=12.33 AFR
Most inexpensive aftermarket wideband setups measure lambda, but then multiply the result by 14.68/14.7 to give you an AFR number on the display. Keep in mind that depending on the fuel that may not be entirely accurate. It’s probably best to ditch using AFR in general to describe fueling, and stick with referencing Lambda values as they are consistent across fuel types.
Hope this helps.
[/quote] What is IAT
IAT is basically a look at the efficiency of the intercoolers. The more air is heated from the initial temperature readings, the less efficient the IC are working. An increase in pressure causes an increase in temperature, but this is where we use intercoolers to try and combat this temperature increase because hotter air means less power.
It’s been mentioned that after 50 deg C the ECU will begin to pull timing to compensate for the poor air conditions and protect the motor. This is an important safeguard and shows the direct effect of quality IC.
Engine speed
Records the reference RPM at which the events are recorded. RPM is corrected (filtered) engine rpm. This should match the tachometer in the dash very closely.
Engine load
A calculation of airflow and RPM. While it’s more complicated than that, its basically the main reference when referencing stored tuning data. For example, 100% is basically a calculation of 100% of cylinder volume being filled with air.
MAF
Mass air flow (HFM), a measure of air flow. This will be actual airflow on stock cars, but may not be accurate on tuned cars, and useless when running MAFless.
IAT
The estimated limit before the ECU begins pulling back on timing advance and fuel mixture on the Mezger engine is ~50-55C.
[/quote]
Thanks to 6speed members who posted valuable information and discussion which I referenced in this thread:
bbywu
Markski
FAST FWD
And many others
I know it’s not terribly relevant to this site, but I was working on it for another porsche forum as a lot of guys seem to have a durametric cable, but many have not dont much logging in the past, or do much more than just send the files to their tuner. I thought this would help encourage people to use the durametric cable as the VAG community does and help see what mods are really making the improvements and such.
But if anyone has any suggestions, or notices anything incorrect, please let me know as I don’t want to misinform anyone.
