DTMR

Do you guys know what the abbreviations stand for when you data log your car? I know IAT is intake air temp, ect is engine coolant, wot is wide open throttle stft1 + 2 are short term fuel trims, but what do all the other ones mean ? so i know exactly what I am looking at

Thanks!

moosestang

I don't know all the abbreviations, but if I'm not sure, then i'll select it, then check it so it pops up as one of the gauges on the live link dash board. That will display the fuel name.

that's assuming you are datalogging with a laptop.

DTMR

I know i hve a mac though and the software doesnt work :/ i need to get myself a little wondows laptop

Doug@C&L

Aircharge temp or IAT in Degree's not Volts
Coolant temp
Cylinder head temp
Short terms banks 1 and 2
Long Terms banks 1 and 2
Load
MAF voltage or ad counts
RPM
Spark

These are a few basic items that will give you some good info. If you have an auto you can also watch these...

Torque Converter lock Duty cycle
Gear Commanded
Gear Actual


Thanks, Doug

DTMR

Wow thanks, what does the abbreviation vpwr stand for?

Doug@C&L

VPWR stands for Vehicle power, basically what the PCM is seeing. This is a good unit to log as if you're at WOT and your VPWR drops then you'll also have fuel pressure drop and other issues.

Thanks Doug

DTMR

Like how much power in what way? ALso what does load mean? sorry I keep bothering you! haha

Doug@C&L

Sorry, that was my mix up.

VPWR is the amount of system voltage your car is reading from the PCM, so it maybe between 13.2-14.8 at any time depending on the condition the car is under.

Load is a calculated value that is based off the engine displacement, that has a tremendous impact on your cars tuning. For example, 1.0 load is the maximum amount that a n/a engine should be able to produce, when you add any type of forced induction your load will go higher then 1.0 because you are forcing air into the engine and therefor it is flowing more then the maximum calculated number.

Load at idle for a stock car should be around .15-.20, cruise anywhere from .3-.6. WOT, .6 and up.

Load has such a huge impact because its one of the values used to calculate Spark, Fuel, and Drive by wire calculations.

When you install a different MAF sensor, like with a CAI, you actually can mess with load because its a larger housing and flows tremendously more air. This in turn can cause load calculations to be off. If you install a larger displacement engine in a car load would need to be corrected by changing the displacement number in the tune.

One thing to note about load when using nitrous after the MAF. The load will go down because the addition gases are not metered by the MAF so it will receive more air but stay at a n/a load value or even drop load. This will have a huge impact on timing and this is why tuning for nitrous is very touchy.


Hope I haven't overwhelmed you as I could go some much more in depth but Im trying to keep it simple.

Thanks, Doug

moosestang

Thanks doug! That was very informative. I knew load was calculated using the MAF value, but I didn't know 1.0 was max load for a NA engine or that .15-.20 was normal load at idle. I've seen a max load of 1.6 during WOT in 3rd gear. Can you guesstimate boost based on load?

DTMR

Wow thanks so much for the info!!