B18B1LS1

iTrader: (12)

Why does my car run better with my Ltrims positive? It is a very noticeable difference. I also get some random knock with my Ltrims inline at slightly negative partial throttle whereas before when they were positive I didn't get any knock anywhere. What else should I be looking into and adjusting once the Ltrims check out good? I haven't changed really anything else besides the basics and the IFR table. My VE table and MAF scales are all still factory settings. Thanks.

Jeffrey

ram-it

I have the same thoughts. My car runs like a raped ape when they are positive and sluggish at negative. The tune I have in now netted me a 113mph trap last night. I am beginning to believe that this LTFT's needing to be negative all the time is BS. Especially with a setup like mine. On a blower car I would think that it would need to be negative.

Another_User

I have been pondering that for awhile too (along with many other LS1 related things too)...I would imagine that based on where you are with the trims it would swing you either slightly rich or slightly lean, because the computer is going to only compensate as much as it has to in order to get to zero. I shoot for negatives because I figure it puts me on the richer end, just to be safe.

patSS/00

iTrader: (6)

For one thing with +ltrims they'll stay + when it goes to a PE (WOT) cell, therefore richer a/f during PE mode. Another possibility is timing: it should be lower timing with +ltrims (I think), so maybe this is helping for some reason, like less knock.

Black02SS

iTrader: (36)

On my car personally, I would like to disagree. Have no clue how I did it, but I must have scaled my IFR table the wrong way, resulting in + ltrims for all my cells. Well, after looking at my log, I noticed on my WOT runs, my LTRIMS lock at 0.....

ram-it

When I go to WOT it normally does not go to 0 for me. The tune that I have where the LT's are always negative it does go to 0 at WOT. But that tune netted me a 110mph trap last night. I installed the one that I liked which the LT's are positive and I picked up 3mph. So, for my car I will leave it as is and try to fine tune it.

B18B1LS1

iTrader: (12)

I know the Ltrims are "supposed" to be negative cruising and 0 at WOT, but it slows my car down. What else can be causing this? I also want to add that when I had a stock tune with positive Ltrims already, I could lean out my car even more via my MAFT and I picked up between .1 and .2 and 2-3 mph. Any tuning suggestions for me would help a lot. FWIW I'm running the 231/237 cam retarded 2 degrees and a few bolt-ons.

Jeffrey

B18B1LS1

iTrader: (12)

According to the not very accurate 02's my car is running pretty rich at WOT. Averaging around .930-.940 mv. Can I just adjust my IFR table to get my Ltrims in check then go into my PE table to correct for the rich condition at WOT without totally screwing my Ltrims back up? Sorry if these are basic questions, I am new to this whole EFI tuning thing.

Jeffrey

gameover

Scaling your IFR's down to richen things in closed loop (moving your ltrims -ve) will make your WOT very rich if you don't lean the PE table out to compensate.