EVO X & Ralliart Cobb AccessPort Data logging explained

Posted by in Brew Crew, Tech on September 05, 2016 . 0 Comments.

Cobb Accessport data logging and gauge display

Learn how to view and review data logs, EVO X Cobb AP.

Data Log: a recording of engine and or chassis sensor data used to diagnose, tune or trouble shoot an EFI engine, suspension or chassis set up. 

The Cobb V3 AccessPort delivers an easy to use hand held or dash mounted gauge/display with full internal Data Logging capabilities and of course the ability to properly re-map/tune the ECU for any build you can dream up. Taking and reviewing a good data log is the best way to "check up" on the health of your Mitsubishi. Ensuring all sensors are reading correctly, all fuel trims are within spec and the ecu isn't trying to pull out any timing is VERY important part of owning any turbo charged car and the EVO X/Ralliart is no different.

V3 Cobb AccessPort Mitsubishi EVO X and Ralliart Parameters: (log these 11BOLD parameters for Etune services, average 7-8hz logging speed.

  • Accel Pos. – The actual position of the Accelerator Pedal as measured at your foot.
  • Active Map – The current Switchable Map slot in use.
  • Baro. Pressure – Barometric Pressure.
  • Battery Voltage – Battery Voltage.
  • Boost – Relative Manifold Pressure (Absolute pressure less Barometric pressure).
  • Boost Corr. – Boost Error (Actual Boost less Target Boost).
  • Calculated Tq. – ECU calculated torque output.
  • Coarse WGDC – Coarse wastegate duty cycle (Passive). (GSR/MR Only)
  • Coarse WGDC Rq. – Coarse wastegate duty cycle request (Passive). (GSR/MR Only)
  • Coolant Temp. – Engine coolant temperature.
  • Exh. Cam. Adv. – Variable exhaust camshaft retard phasing position (Actual).
  • Exh. Cam. Targ. – Exhaust cam advance (Target).
  • Fine WGDC Rq. – Fine wastegate duty cycle request (Reactive).
  • Gear - Current – Current gear as reported by the TCM. (SST Only)
  • Gear - Next – Next gear to be used as reported by the TCM. (SST Only)
  • Ign. Advance – This is the final commanded ignition timing after all correction and adjustments.
  • Inj. Duty Cycle – Duty cycle measurement of fuel injector use.
  • Inj. Pul. Width – Total open time of fuel injector.
  • Int. Adv. Targ. – Intake cam advance (Target).
  • Int. Air Temp. – Measurement of intake air temperature at the MAF location.
  • Int. Cam. Adv. – Variable intake camshaft advance phasing position (Actual).
  • Knock Sum – An incremental counter based on knock sensor feedback. A count of three will result in 1° of timing pulled from the ignition map.
  • LTFT Cruise – Long Term Fuel Trim during cruising conditions.
  • LTFT Idle – Long Term Fuel Trim during idle conditions.
  • LTFT Used – Long Term Fuel Trim currently being used.
  • Learned Knock – A percentage used to determine crossover points between High/Low octane tables.
  • Load – This is the calculated load used to reference various table look-ups.
  • Load Ref. Calc – A blended version of Calculated Load based on MAF/MAP sensor calculations.
  • MAF – Mass air flow sensor output in grams per second of air flow by mass.
  • MAF Calcs – Calculated Load based on MAF sensor calculations.
  • MAF Voltage – Mass air flow sensor output voltage.
  • MAP Calcs – Calculated Load based on MAP sensor calculations.
  • Manifold Temp. – Manifold Air Temperature Sensor output.
  • RPM – Engine speed in revolutions per minute.
  • Reported TQ to SST – Torque Reported by the ECU to the TCM for SST actions. (SST Only)
  • SST Cal. Tq. Multiplier – Allowed torque percent for SST. Will drop during shifting. (SST Only)
  • SST Clutch Status – Displays the clutch/de-clutch status. (SST Only)
  • STFT – Short Term Fuel Trim currently being applied.
  • Speed Ratio – The ratio of engine RPM to wheel speed.
  • Throttle Angle – The throttle position as determined by the Request Torque tables.
  • Tip in Transient – A derivative of throttle position during engagement of the accelerator pedal.
  • Tip out Transient – A derivative of throttle position during disengagement of the accelerator pedal.
  • Vehicle Speed – Speed reported by vehicle speed sensor.
  • WB AEM AFR – Log from the rear O2 input to ECU from AEM UEGO O2 sensor.
  • WB LC-1 AFR – Log from the rear O2 input to ECU from LC-1 Wideband O2 sensor.
  • WGDC Corr. – Wastegate duty cycle correction applied.

WB AFR set up/wiring:

You only need to select 1 WB AFR parameter (to match your wide band o2 gauge/controler) Before you can log your wideband o2 sensor you will need to connect the 0-5v signal from the wide band AFR controler/gauge to the rear o2 sensor input. This replaces the otherwise useless rear o2 sensor data with the VERY important wide band Air Fuel Ratio data. 

If you need more help getting your Cobb AP set up, custom Base Map or your current tune dialed in check out E-tune options and feel free to contact us any time. Don't have a Cobb AP? No problem we tune just about everything, click here to check out our Tuning page for a list of supported ECU's and the latest projects. Contact us any time sales@brewedmotorsports.com or 888-290-3213 **We are often in the shop or at the track so please leave a message and we will call you right back!**

DIY Cobb AP Tune upload and firware upgrade:

Opening and reviewing your Cobb AP data log in MS Excel

Once you have opened the data log the first step to easy reveiw is to "freeze" the top row so that as you scroll through the log you can still see the sensor name/data name in the top row. **NOTE** you can see in the log below the wide band AFR (AEM) data is no correct, this is caused because the signal wire has NOT yet been wired to the rear o2 sensor input. 

evo X cobb accessport Etune and data log

Below is a BAD/DANGEROUS data log, the Etune customer is NOT following data log instructions.

The log below is an early log from an EVO X with the rev limiter set to 4500rpm to ensure the engine can not be driven hard until low load/rpm ranges can be logged and everything is verfied to be working correctly and running smooth/safe. As clearly stated on the Mitsubishi Etune page here: Cobb AP Mitsubishi Etune these logs should be taken from: "Low throttle (~ 20% throttle from idle to 4000 rpm)**holding throttle steady is the most important factor here, do not change the throttle position during the log.**" The log below you can clearly see the engine is being held above the 4500rpm limiter for over 2 seconds with the throttle still held open to ~ 17-24%. The correct and SAFE way to take this log is exactly as described on the Mitsubishi Etune page linked and quoted above, ending the log and lifting OFF the throttle 100% as soon as you reach the uper RPM limit of the requested log is a VERY important part of taking safe responsible logs for your Etune. Hitting a rev limiter is ok BUT should be avoided and the engine should NEVER be held on or above the rev limiter.

In the log below you can also clearly see the "knock sum" is 0 and the AFR is richening up nicely into the mid 12s as the engine transitions into low boost and moves up the rpm range. 

example of bad/dangerous data log, HOW NOT TO DATA LOG

Know your limits

Above and beyond following your tuners instructions and taking good/safe responsible data logs, it is just as important to ensure all aftermarket or OEM parts are installed correctly and working as they should. If you are not familiar with installing parts (mechanic work) or doing basic wiring DO NOT guess or try and figure something out! We totally understand the satisfaction of accomplishing a complex task such as installing performance parts and learning along the way, BUT we also understand not everyone is a mechanic. So if you find yourself not understanding something a 110% and/or are unable to follow the manufactures instructions you should stop what you are doing and make an appointment to have a professional complete the work before something is damaged. Don't put yourself in a bad situation, take your time and if you find yourself in over your head stop where you are and seek the assistance of a professional mechanic.


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