Newbie LTFT question

[dmtnt]

When analyzing LTFT's I need to look at the average from both banks, correct? After installing my new Vararam intake, I logged about 40 miles worth of data and the average LTFT is 12.3. I know I need to get them to 0 or slightly negative, but just want to confirm I need to look at the average. Thanks! :D

[FastAl]

Yes look at averages for both banks and look at what cells they are in. You don't need to do much if anything with idle cells. I've got the info at home as too want cells you need to care about.

[dmtnt]

Thanks FastAl. I'm using the tuning analysis spreadsheet from "NBM-WS6 Driver". It shows the "Average LTFT at Load" to be 12.3. This is the number I need to drop, correct?

[JandJsTA]

You may want to start with the averages but to polish off the job at the end you don't want "any" of the 6-14 LTFTs cells to be + so don't be fooled by the avg sitting at -1 or -2. If you have any of the fuel cells sitting in the + range and at that very point in time you go to WOT that + number will be added to your PE A/F and you will most likely be running rich or richer then your best HP A/F . So if possible have ALL of your fuel cells from 6-14 flat or slightly - to ensure this doesn't happen ... not just the average :)


Have a look through the Tuning thread at the top of this page ... some great info in those sites :)

[dmtnt]

Originally posted by JandJsTA
You may want to start with the averages but to polish off the job at the end you don't want "any" of the 6-14 LTFTs cells to be + so don't be fooled by the avg sitting at -1 or -2.

Thanks Joe. I've read so much on this that my head is spinning. Its alot to grasp at first. Here's something I noticed - there are no data points for cells 12 and 13. Is this normal? Maybe I didn't hit these cells during my logging?

[JandJsTA]

Originally posted by dmtnt
Thanks Joe. I've read so much on this that my head is spinning. Its alot to grasp at first.

he he... welcome to the club.. as you go along it will get a lot clearer ... clear as MuD :rubeyes:

Originally posted by dmtnt
Here's something I noticed - there are no data points for cells 12 and 13. Is this normal? Maybe I didn't hit these cells during my logging?

Some of us never see all of the fuel trims... and sometimes you need to log for hours up and down the RPM band before you see some... don't worry about it... if they show up they do ...if not you may never see them :)

[jimmyblue]

I don't think you want to muss up your mind with
averages etc. You want the LTFTs -in any cell you
can hit WOT from- to be slight negatives. That's
basically all of them, unless you are likely to roll
the pedal on slowly all the time.

I know I have idle LTFTs approaching -10 and
mid-throttle they are down around -1. It wouldn't
take much to have me averaging -4 and still have
occasional positives lock in. And how would you
average anyway, to take out the discrepancies in
time-spent-in-cell?

If you have Excel it would be easy to scatter-plot
LTFT against FTC and get a real simple, clear idea
of where you sit.

[smiley]

sounds liek you are starting out pretty good. soon you'll become addicted like the rest of us ;) here is some info for some of your ftc.....

http://smiley.tzo.com/fbody/atap/atap_ftc.htm