LS1 Edit -- adjusting LTRIMs on an already dyno tuned car?
Thread Starter
TECH Senior Member
Joined: Nov 2001
Posts: 7,036
Likes: 1
From: Lake Zurich, IL
LS1 Edit -- adjusting LTRIMs on an already dyno tuned car? My car's already been dyno tuned so WOT fuel should be right on...
However, the tuning was performed after a new motor install (382) so I don't think there was much driving time on it
I autotapped the car and averaging FTCs 1-19 I get 12/13% for LTRM1 and 2 ...
So 2 questions:
1 what table do I modify in LS1 Edit to bring these down to 0? I've searched and some say the MAF table some say the IFR table (car's running 42lb injectors if it matters) which is it?
Also how much do I scale them?
2. If I modify either of these tables will it mess up my WOT tune? if so no real big deal as I have a wideband O2 ...
Thanks!
However, the tuning was performed after a new motor install (382) so I don't think there was much driving time on it
I autotapped the car and averaging FTCs 1-19 I get 12/13% for LTRM1 and 2 ...
So 2 questions:
1 what table do I modify in LS1 Edit to bring these down to 0? I've searched and some say the MAF table some say the IFR table (car's running 42lb injectors if it matters) which is it?
Also how much do I scale them?
2. If I modify either of these tables will it mess up my WOT tune? if so no real big deal as I have a wideband O2 ...
Thanks!
TECH Apprentice
Joined: Dec 2001
Posts: 357
Likes: 0
From: Whitby Ont Canada
Originally Posted by horist
My car's already been dyno tuned so WOT fuel should be right on...
However, the tuning was performed after a new motor install (382) so I don't think there was much driving time on it
I autotapped the car and averaging FTCs 1-19 I get 12/13% for LTRM1 and 2 ...
So 2 questions:
1 what table do I modify in LS1 Edit to bring these down to 0? I've searched and some say the MAF table some say the IFR table (car's running 42lb injectors if it matters) which is it?
Also how much do I scale them?
2. If I modify either of these tables will it mess up my WOT tune? if so no real big deal as I have a wideband O2 ...
Thanks!
However, the tuning was performed after a new motor install (382) so I don't think there was much driving time on it
I autotapped the car and averaging FTCs 1-19 I get 12/13% for LTRM1 and 2 ...
So 2 questions:
1 what table do I modify in LS1 Edit to bring these down to 0? I've searched and some say the MAF table some say the IFR table (car's running 42lb injectors if it matters) which is it?
Also how much do I scale them?
2. If I modify either of these tables will it mess up my WOT tune? if so no real big deal as I have a wideband O2 ...
Thanks!
The injectors have been upgraded so IFR table is the way to go ..... as far as the tune(try logging FTC 6-14 first and see what you get) I would have to believe that if the LTFTs were that high when it was dynoed they tuned WOT with that added fuel in the PE mix .... which means lowering the LTFTs now WILL have an effect on your WOT tuning ... making you lean ... be careful
Thread Starter
TECH Senior Member
Joined: Nov 2001
Posts: 7,036
Likes: 1
From: Lake Zurich, IL
ok cool...
I looked at my logs (i have 5 logs ... total of about 20,000 records ) from atap and averaging only FTCs 6-16 I'm about the same... 12.5 1 side, 13.9 other side
So should I scale the IFR table up or down? (multiply by >100% or <100% ?)
Also since I'm changing this should I then scale up the PEvsRPM table to be safe? Then take it out on some WOT blasts w/my Wideband O2?
Thanks!
I looked at my logs (i have 5 logs ... total of about 20,000 records ) from atap and averaging only FTCs 6-16 I'm about the same... 12.5 1 side, 13.9 other side
So should I scale the IFR table up or down? (multiply by >100% or <100% ?)
Also since I'm changing this should I then scale up the PEvsRPM table to be safe? Then take it out on some WOT blasts w/my Wideband O2?
Thanks!
Changing your IFR table will *always* affect WOT just as much as partial throttle. It affects all aspects of driving.
Plus, as J&JsTA stated, the tuner tuned with the LTrims not locking to zero, which means the computer was dumping 12.5% or so of fuel in there at WOT as a result of Ltrims and not as a result of PE vs RPM table. So if you fix the Ltrims, your A/F will be further out of whack.
I had a tuner tune mine, but he just dyno tuned and didn't really do much partial throttle tuning. So I went home and tuning it around the street myself. Then I brought it back to a dyno and just did the WOT tuning myself. FYI my A/F ratio went from 11.8 to 13, so its very important to go back to the dyno...
Oh and with the IFR table, SMALLER values means MORE fuel, LARGER values means LESS fuel. So basically it's reversed. The PEvsRPM table is standard (higher values means more fuel).
Plus, as J&JsTA stated, the tuner tuned with the LTrims not locking to zero, which means the computer was dumping 12.5% or so of fuel in there at WOT as a result of Ltrims and not as a result of PE vs RPM table. So if you fix the Ltrims, your A/F will be further out of whack.
I had a tuner tune mine, but he just dyno tuned and didn't really do much partial throttle tuning. So I went home and tuning it around the street myself. Then I brought it back to a dyno and just did the WOT tuning myself. FYI my A/F ratio went from 11.8 to 13, so its very important to go back to the dyno...
Oh and with the IFR table, SMALLER values means MORE fuel, LARGER values means LESS fuel. So basically it's reversed. The PEvsRPM table is standard (higher values means more fuel).
