Does anyone have a good guide or tips of what to look for on a log. What the specific values mean, which are most important etc??

 

Super depends what you're trying to do. When you're trying to figure out gremlins, you want to log limits and sources. When you're tuning the transmission you wanna log output shaft speeds, solenoids, line pressure, rpm etc etc.

It's not cut and dry.

 

Never done it but spark advance and A/F mixture seems like things to look at that would be important.

Mike

 

Most tuners can give you a log file along with instructions on how they want you to log the vehicle to get the info needed. Then you can look at your logs and see what they normally look at. Coolant temp, air temp, maf flow, timing, air fuel from wideband readings, throttle position, the list goes on and on of important info.Typically you do a cold start, idle for a few minutes to warm up, rev to 3-4k and hold, then drive for a minute at cruise, then a full pull from about 2k-redline in 3rd gear. This gives a variety of engine conditions that a tuner would want to look at. This is my 4th Ford vehicle I have had tuned and logged. I have worked with 5 different tuners (Lund was the best with instruction for logging). I prefer using SCT but NGauge and HP tuners are also great options.

 

Knock sensor data is one of the primary values tuners use to determine just how far they can bump timing for power increase.
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I appreciate the responses. I probably worded my question a little goofy. I do know how to log. I just really don't know what I'm looking at as far as values with the data.

 

Me personally for the purposes of daily logging to make sure it doesn't explode (and not for tuning), I look for
ECT (engine coolant temperature)
IAT2 (intake air temp)
Air Fuel ratio or lambda
Knock
Boost
Total spark advance
Catalytic converter temp
Engine octane ratio (more important for ecoboost trucks as opposed to 5.0)

For tuning purposes my Tuner is also logging cam and valve settings, and transmission perimeters. None of those things I display on a daily basis or even pay much attention to.