Data Logging

[mjohns930]

I got my SCT X4 yesterday and I want to do some data logging. What PIDs are the best to log? What kind of pulls should I be doing to get a good read on what it's doing?

My car is not tuned (yet) I just want to get a feel how it runs stock first.

Thanks

 

[VETTEHUNTER]

Most tuners will want these:

RPM
Knock
Spark
Spark V2
Maf lb/min
Maf Frequency
Load as a fraction
Actual Throttle Angle
Intake Air Temp
Long Term Fuel Trims
Short Term Fuel Trims
Lambse B1/B2
Measured Air Fuel

 

[mjohns930]

Most tuners will want these:

RPM
Knock
Spark
Spark V2
Maf lb/min
Maf Frequency
Load as a fraction
Actual Throttle Angle
Intake Air Temp
Long Term Fuel Trims
Short Term Fuel Trims
Lambse B1/B2
Measured Air Fuel

Thanks VETTEHUNTER.

Now, what sort of pulls should I make? Should I do like WOT 2000 rpm to redline in third or fourth? Run it through the gears in the quarter mile?

 

[VETTEHUNTER]

Thanks VETTEHUNTER.

Now, what sort of pulls should I make? Should I do like WOT 2000 rpm to redline in third or fourth? Run it through the gears in the quarter mile?

No problem. I got this from another member who was data logging for AED I believe:



"I want 2 logs:

1. Part throttle in 3rd very slow acceleration from 1100 to 5K followed immediately by a few minutes of idle.
2. WOT from 2K to Redline (Preferably on a Chassis Dyno) *5th gear for manual's, 4th for Auto's when on the dyno*
Or 3rd or 4th gear on the street.

Doing the idle log after a part throttle pull ensures the O2 sensors are up to proper operating temps for accurate data at idle.
This is especially important for Long Tube applications.

Part throttle log can be done on the street in 'real world' conditions. WOT can be done at a track or on a chassis dyno."

 

[03cobra#694]

Might want to use 3rd because you'll be hauling in 4th.

 

[mjohns930]

Awesome. Thanks! Now to get some logs and figure out what they mean.

 

[mjohns930]

Alright. I have made some logs and I am trying to figure everything out. There are a couple PIDs I need explained to me:

Knock Sensor - I know what the knock sensor is/does, but I want to make sure I understand the read out in the data log. I get positive and negative values and I am assuming that is how much timing it is adding or subtracting. Am I on the right track with that?

Spark Advance and Spark Advance v2 - I know this is ignition timing, but why two? Is one commanded and one actual? What is what here?

Lambse 1 & 2 - This is obviously AFR as lambda, but there is also Measured AFR 1 & 2. So is this commanded lambda? Also, how do I calculate a regular AFR (12:1 for example) out of this if I am on E10 gas?

Here (link to my Dropbox) is a link to one of my data logs doing a WOT pull from 2000-6800rpm in third gear (auto). If anyone could take a look at it and answer a couple questions for me that would be awesome.

In the 2300-2800rpm range the knock sensor looks like it pulls some timing and then starts going back up to zero. Then there at 5000rpm it looks like it adds a little and then goes back to zero. Not sure I understand why that is happening since I can't see it pulling or adding timing at those spots, then again, I am not 100% certain of everything I am looking at. So what does that mean?

Then, from 3900rpm on up the spark and spark v2 take a lot of dips. It is really bad from 3900-5500rpm. Why is that happening? I don't see anything happening on the knock sensor, so that leads me to believe it might be tune related.

Thanks for taking the time to read all this, and thanks in advance for answering any of the above questions.

Mitch

 

[grnenvy]

If its an auto u need to pull all the gears to check shift points.

 

[mjohns930]

If its an auto u need to pull all the gears to check shift points.

It is stock tune right now, so I'm not that concerned with that. Although when the time comes for a tune that will be a consideration.

Thanks.

 

[LeKiD]

Positive knock remove and negative knock add timing .

Stock tune is shit . Needs lots of works .

 

[mjohns930]

Positive knock remove and negative knock add timing .

Stock tune is shit . Needs lots of works .

Ok, I was kind of thinking that about the knock sensor being opposite.

As far as the stock tune being junk, yes, I know that. But what I want to know is why some stuff is happening. Like the timing dips in the mid range. Why is that happening? Is there some other influence other than what I can figure out?

 

[castro_5o]

Intake Air Temp
Lambse B1/B2
Long Term Fuel Trims (bank 1 and 2)
Measured Air Fuel
Short Term Fuel Trims (bank 1 and 2)
Maf Frequency
Maf lb/min
RPM
Load as a fraction
Knock
Spark
Spark V2
Actual Throttle Angle
Variable Valve Timing Intake Bank 1
Variable Valve Timing Exhaust Bank 1
MPH
Torque converter Speed Ration (Auto only)