Cobb Logging Parameters/Values - what is safe/acceptable for each values - Draft 1.
 

Please make sticky if this thread is helpful to everyone.

Guys, I would like to put a combined knowledge of all pro/tuners/anyone with knowledge of whats the safe parameters / values should be and what they mean when logging with the cobb ap for best performance.

The purpose of tuning is to have the Evo X make the most power when run lean with the maximal amount of ignition timing that the ECU will allow without detonating/knock.

There are little bits of pieces of information in many threads. With everyone's help in your comments below I can come back to edit these values and make a "Go To" sticky thread for everyone to look at.

I got the below from Cobb Access Tuner's Tuning Guide. Its a good read. But does not tell me what values/ parameters each of these should be. Feel free to have a read.
http://www.accessecu.com/support/doc...bishi_EVOX.pdf

Courtesy of Cobb's website. Almost all information I've gotten from here is from Cobb. I am not a professional tuner.

And different version of cobb ap software will have different values. Let me know what to add/remove. I currently do not have a Cobb AP. but will later. Im sure most of us would like to know how our car runs and what our car is trying to tell us. If not, we never would've gotten an Evo X, or traded it in after 36,000 miles like my previous owner did. And I believe, our EVOs are all very lucky to have us.

So, What should these values be? What do they mean? What is a safe range? What is the exact number we want? For optimal performance that is SAFE. And most importantly, how these values correlate and affect another.



- Abs. Pressure (absolute pressure) -
- Accel. Pedal Pos. (V) (voltage relates to low and high position) -
- Baro. Pressure -
- Battery Voltage (V) -
- Boost Pressure (relative manifold pressure) (boost pressure = absolute pressure - barometric pressure) (stock can take as high as 30psi but will damage cylinders) - Cobb maps sets them at 25psi.
- AFR - high 11(low quality fuel) to low 12(high quality fuel) -
- ECT (engine coolant temperature) -
- Exhaust Cam. Ret. (variable exhaust camshaft retard phasing position) -
- Ign Advance (ignition timing in degrees before top dead center. this is the final commanded ignition timing after all correction and adjustments) -
- Inj. Duty Cycle (duty cycle measurement of fuel injector use)-
- Inj. Pulse Width (ms) (total open time of fuel injector) -
- Intake Air Temp. (measurement of intake air temperature at the MAP location) -
- Intake Cam. Adv (variable intake camshaft intake phasing position) -
- Knock Retard (CA) -
- Knock Sum - -0.35 = 1 degree. Anything more than 2degrees you should pay attention to. Anything less than 2 is normal or impossible to tune out. Random values besides zeros on each pull is ok. Consistent values on same rpm and same gear pulls you should pay attention to. So what do we do when we see knock we should pay attention to and worry about? Get an Access Tuner and tune it out? How do we do that?
- LTFT (long term fuel trim) -
- STFT (short term fuel trim) - LTFT + STFT = zero or +/- 8 is good (for intakes other than the ones provides by Cobb Maps. For example: ETS intakes.
- Learned Knk. Ret % -
- Load Boost/Fuel -
- Load Limp Mode -
- Load Timing -
- Low Det. Weight -
- MAF (V) -
- MAF (g/s) -
- MFD-AFR (logged external WBO2) -
- RPM -
- Speed Ratio (RPM/Speed) -
- TPS Voltage (reported voltage of throttle position sensor) -
- Throttle Position (percentage of throttle opening 0-100%) -
- Vehicle Speed -
- WGDC Coarse % -
- WGDC Fine % -


Go EVO !

I think your description of knock sum should read: 0.35 knock retard = 1 knock sum

anybody else?

really wish someone would chime in here. I just got the cobb AP and am doing logging and would love to be able to read and diagnose the chart by myself instead of posting logs on here and asking if it's okay.