Wonder if the tuning guru's could offer the pros/cons of tuning the MAF by disabling the LTFT & using the STFT instead. If you are using an average value in your Histogram anyway, this would seem to accomplish the same thing, but just be less time consuming. Am I overlooking something?
I haven't tried it to prove or disprove the thought, just curious as to the thought process behind using LTFT as most people suggest, as I'm relatively new to this fascinating hobby.
I would leave the LTFT's enabled. Then set up a user defined STFT+LTFT PID. Then insert this PID into your Maf histogram. Using STFT's is not accurate because they will always be moving ~2-4% even when the LTFT's are learned.
Russ Kemp
The only benefit is it's a short procedure, takes very little time and will get you working quick when you install a lot of mods at once.
The only downside to STFT's is that you need to keep it in a cell for a few seconds to log 20+ frames so that you get a good average. Otherwise the LTFT's are simply an average of an average.
Thats where a load bearing chassis dyno becomes your best friend.
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I like Russ's LTFT + STFT suggestion....I'll be using that one. Russ, do you use the same LTFT + STFT for VE tuning too?
I use a wideband for tuning the VE table.
Russ Kemp
Without having the PRO version is there a way to integrate my chassis dyno's wide band with the logger? Having trouble finding any info on this...
If your chassis dyno has analog outputs for the wideband you are golden. Otherwise SOL.
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I believe it does. At least it should it's a brand new dynojet with load control.Originally Posted by EC_Tune
How do I proceed if so? I couldn't find a topic on this...
Thank you.
I have a new one at the shop but I'm not aware of any analog outputs on the DynoJet.
Might want to PM DynoDan
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You are correct, I just talked with tech support. There are no analog outputs on the Dynojet. That seems pretty silly to me.
I'm just trying to utilitze the histogram function for VE tuning. Is there another table that would be a decent substitute for the AFR Error, would STFT+LTFT for VE be ok to use the paste special with?
Last edited by FirstGen; 02-01-2008 at 11:57 AM.
I spent a few hours using the LTFT + STFT custom PID to dial in about 90% of the VE tables on a Cavalier recently. Worked very well, and went much quicker than it was taking using just LTFT. This will be a regularily used function for me. I put in a cell count in the histograms of 20 so that the histogram wouldn't put up a value until we had a good average to go on.
Thanks for the good tip Russ, much appreciated,
What other steps are you taking before logging the LTFT + STFT PID. Dis-able DFCO? Anything else? Still trying to figure out all of this stuff and it seems there are many opinions and methods to similar outcomes. I would like to understand several methods and try each for myself.
so if your STFT's are -8, but your LTFT's are -2....should you compensate with -10? ive only been using the LTFT's to tune the MAF..my LTFT's are pretty close to 0, but the ST's are all over. or should i only tune the maff off the STFT's on a long scan were i get alot of values for each table.
I set the PE enable TPS as high as you are comfortable, disabled DFCO, and put a cell count in the histograms for about 20 hits or so so that I got a good average.
How does one go about setting up the LTFT+STFT customer PID?
Just trying to learn something new
im wondering as well, i cant seem to log stft + ltft. ive tried, im doing something wrong in the histogram
Go into the table you select the PIDS/sensors you want to log. When you right cliick to insert a new sensor, you'll see an option - Configure User Defined. Here you can create your own PID. When the screen pops up to define your PID, you'll see an area at the bottom where a function is allowed. Enter [SENS.114]+[SENS.116] in this area (or which ever PID/sensor you are logging for long & short term fuel trims).
Shane, what value is needed in the units? Percentage? Anything needed in the Sensor drop down?
When finishing up the tune, do you put all the DFCO values back to stock or should they be modified any?
Stock values in this case are:
Enable Temp: 86F
Disable Temp: 77F
Enable RPM: 1300
Disable RPM: 1200
Last edited by FirstGen; 02-04-2008 at 11:12 AM.
The units are percent just like LTFT & STFT are, putting that in is optional. Nothing is requried in the sensor drop down. I returned DFCO to the original values afterwards.
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