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View Full Version : Lterms 0 out on motor, but when I spray they go positive?



Loudmouth LS1
February 14th, 2007, 05:48 PM
Just curious why this is and if there's any way to fix it? I dialed in the maf usin the map for it to get the actual afr to match what I was commanding in the pe vs rpm table for wot like everyone said to do, and the lterms 0 out on motor, but when I spray it, they go positive? Is this normal, is it going to affect anything? I'm using a wet kit, so the computer shouldn't be affected by the extra fuel, right? Could the change in wot timing affect it (had 27 for motor, 20 for spray) or the fact that I had #8 plugs in instead of #6's?

dfe1
February 15th, 2007, 04:07 PM
I'm a little confused. I'd assume you only spray at WOT and under those circumstances LTFTs should be zero, unless they're a good bit off during the transition to WOT. Once you transition into PE, learn control is turned off, so LTFTs should be unaffected whether you spray or not. If you're hitting the switch before you're in PE, the additional oxygen introduced by the nitrous could be what's causing the LTFTs to move.

Loudmouth LS1
February 17th, 2007, 01:39 AM
I'm a little confused. I'd assume you only spray at WOT and under those circumstances LTFTs should be zero, unless they're a good bit off during the transition to WOT. Once you transition into PE, learn control is turned off, so LTFTs should be unaffected whether you spray or not. If you're hitting the switch before you're in PE, the additional oxygen introduced by the nitrous could be what's causing the LTFTs to move.

Spray comes in off a wot switch, also, weird thing I noticed last night, I was only spraying a small shot last night, so I left the #6 plugs in and the lterms zeroed out, could the #8's make things weird?

dfe1
February 17th, 2007, 03:44 AM
Anything is possible, but you may just be seeing run-to-run variations. In theory, hotter plugs should result in more efficient combustion, but I wouldn't think the difference would be enough to seriously affect LTFTs. If it was, I think you'd also see an increase in detonation under full load. I'm still a bit mystified about the LTFTs changing under WOT. Can you post a data log file?

Loudmouth LS1
February 17th, 2007, 03:57 AM
Anything is possible, but you may just be seeing run-to-run variations. In theory, hotter plugs should result in more efficient combustion, but I wouldn't think the difference would be enough to seriously affect LTFTs. If it was, I think you'd also see an increase in detonation under full load. I'm still a bit mystified about the LTFTs changing under WOT. Can you post a data log file?

Yeah, i'll post 'em up later when I can get on the laptop.

I don't think it was run to run variations, cuz I made like 4 runs last night, logged 'em all and it was all zeroed out, although maybe the one run on the 8's was a fluke, cuz that was a couple weeks ago and it was only one run and I was planning on hittin a big shot but only hit a small one.