LTFT's "Disabled"...good, bad, or otherwise???
Feb 6, 2011 | 03:57 PM
#1
Thread Starter
11 Second Club
iTrader: (42)
Joined: Nov 2005
Posts: 1,643
Likes: 4
From: Baltimore, MD.
LTFT's "Disabled"...good, bad, or otherwise???
Normally, I only have my LTFT's enabled while tuning VE. Have them disabled while doing MAF tuning and after tuning is done. Never an issue with WOT PE/AFR that way, obviously, but aside from VE tuning, for what other reason should I keep them enabled?
I had to richen up the tune a bit since adding a 4" intake tube to take advantage of the room I have after doing an electric fan conversion. It wasn't way off, but I did some tweaking anyway. Right now my LTFT's are + or -3 or less, MAF is 1% or less, and STFT's are generally + or -2 or less.
Is there any disadvantage to having the LTFT's disabled?
There seems to be absolutely no effect (one way or the other) on gas mileage or performance, FWIW.
I had to richen up the tune a bit since adding a 4" intake tube to take advantage of the room I have after doing an electric fan conversion. It wasn't way off, but I did some tweaking anyway. Right now my LTFT's are + or -3 or less, MAF is 1% or less, and STFT's are generally + or -2 or less.
Is there any disadvantage to having the LTFT's disabled?
There seems to be absolutely no effect (one way or the other) on gas mileage or performance, FWIW.
Feb 7, 2011 | 09:23 AM
#2
I do not run LTFT's.
Only benefits IMO is if you develop an intake leak, it will compensate a richer mixture and also carryover to your Pe whereas STFT's will not. Since LTFT carry over to Pe, it could help if you had a nasty leak and didn't recognize it. And the other is to compensate for varying fuel mixtures with the "up to" 10% ethanol blends. I see swings as much as 0.5AFR in Pe from pump to pump.
Only benefits IMO is if you develop an intake leak, it will compensate a richer mixture and also carryover to your Pe whereas STFT's will not. Since LTFT carry over to Pe, it could help if you had a nasty leak and didn't recognize it. And the other is to compensate for varying fuel mixtures with the "up to" 10% ethanol blends. I see swings as much as 0.5AFR in Pe from pump to pump.
Feb 7, 2011 | 09:55 AM
#4
I do not run LTFT's.
Only benefits IMO is if you develop an intake leak, it will compensate a richer mixture and also carryover to your Pe whereas STFT's will not. Since LTFT carry over to Pe, it could help if you had a nasty leak and didn't recognize it. And the other is to compensate for varying fuel mixtures with the "up to" 10% ethanol blends. I see swings as much as 0.5AFR in Pe from pump to pump.
Only benefits IMO is if you develop an intake leak, it will compensate a richer mixture and also carryover to your Pe whereas STFT's will not. Since LTFT carry over to Pe, it could help if you had a nasty leak and didn't recognize it. And the other is to compensate for varying fuel mixtures with the "up to" 10% ethanol blends. I see swings as much as 0.5AFR in Pe from pump to pump.
Feb 7, 2011 | 10:02 AM
#5
Thread Starter
11 Second Club
iTrader: (42)
Joined: Nov 2005
Posts: 1,643
Likes: 4
From: Baltimore, MD.
The main thing I don't like is that if you go WOT, and the LTFT's are way off, so will your WOT afr. From what I have read, PE adds or subtracts fuel depending on what the LTFT's have said it needed at PT...which seems to be counterproductive and erratic, if that is true.
Feb 7, 2011 | 10:10 AM
#6
I have never experienced fuel being added or subtracted when in open loop p.e. I always disable te ltft's and the stft's for tuning ve and maf, once thats dialed in I will enable them again and check trims.
Feb 7, 2011 | 10:35 AM
#7
Yep that is what i do.... Tune everything with the Wideband, then enable all the trims afterwards and then if the trims are off i tweak the switchpoints to bring them inline....
