ok...i think i have heard that when you put on long tubes your afr changes do to the o2 sensors move further back. before my afr was at 13.0 and now its around 14.7 slowly goes down to 14.0.... does long tubes make that big of a difference. is my computer trying to stay at stoich at wot or do i have to change my pe table...
You need to change your VE table, not your PE table. You'll have to change your MAF table too if you're still running one...
2011 Z07 Carbon Edition
You want to determine whether this is a real AFR skew
from airflow (VE), or a closed loop skew from something
like the sensors running colder and acting -as if- lean,
and the loop "correcting" to a real-righ, indicated-stoich
point.
Most likely the latter, because at idle andlow cruise the
exhaust is not a meaningful restriction nor doing the
resonant extraction that the long primaries are meant
for.
ok...i already went ahead and tuned my ve and maf table. my ltft are either zero or close to zero. the lc1 wide band is at or around 14.6 on idle or cruzing, so im guessing the wideband is working well. once i floor it, it stays at a constant 14.1 14.2. so im going to try to richen up the pe table. before it was at 1.170, which when divided by 14.62857 is around 12.5 but with wideband was 13.0.
Friends don't let friends rape PE tables.
Set your PE table to whatever AFR you want to command when WOT. Then tune the upper regions of the VE or MAF so you are achieving your commanded AFR just like you did for the non-PE regions.
Bill Winters
Former owner/builder/tuner of the FarmVette
Out of the LSx tuning game
Originally Posted by 5_Liter_Eater
Hahaha.......that's funny!
But seriously though 5 Liter couldnt have said it any better, do it the correct way and you will be much happier with the end result.
Last edited by KLUG'S SS; 09-10-2010 at 08:56 PM.
2017 Silverado LTZ
Exactly as they have said you set your PE first just like your injector size and never touch it again until ALL tuning on the VE and MAF are done. You change the VE then MAF to get the WB to match the commanded AFR which at WOT is modified by the PE table. That way once you have done the VE and MAF, a change to the PE will equal the right amount you see on the WB. So you can later tune for max power or best power and safety without messing with VE and MAF.
If you are runing E10 fuel that is why it 14.10-14.2 and 14.67 with E10 it is 14.2
2002 CE T/A M6
ET 1/4 mile 12.21 before hp tuners!
SLP headers, Hi-flo cats, loud mouth, Mcleod twin disc clutch, Mcleod throw out bearing, Ported TB, TB by pass, ELE.water pump, 160 stat, 12 bolt, 411 gear, MTI lid,SLP bellows, SLP maf no resistor ,Under drive pulles, Removed Air pump, Spohn PRO Ajustable torque arm,QA1 12 way ajustable shock up front, Spohn pro drag sway bar, Spohn Rear Ajustable LCA, AEM A/F gauge and a Set of Bogart w/27'' tires
Yes and no.
While stoich for E10 is more like ~14.2 the wideband (or narrow bands) don't know whether the fuel is E0, E10, E85, C16, etc. Unless the wide band is configured to display differently (and the Innovate WB's are the only ones I know that can do this) it is going to display stoich (of any fuel) as 14.7. The wideband (and narrow bands) are reading lambda, or stoich, for whatever fuel is being burnt. The wideband is just displaying the AFR based on an offset and slope derivation of lambda.
Bill Winters
Former owner/builder/tuner of the FarmVette
Out of the LSx tuning game
ok....im slowly manually tuning the top of the maf and finally im not hitting 14.7 or 14.2 at WOT.. i got it to 13.6 so far but i still have more tuning to do....thanks for the help guys....at least i know im on the right track
Why slowly and manually? Learn to use the histograms. Plot the AFR error against the MAF table and then copy & paste special (multiply by %) into the tune. Do this maybe twice and you should be almost spot on.
Bill Winters
Former owner/builder/tuner of the FarmVette
Out of the LSx tuning game
If you change anythigngo do with the volumetric efficiency of the engine you will meter slightly different AFRs - but not enough to make a significant power difference just by fitting LTs. I would say it is your O2 sensor that is being more affected by a less than perfect position into the exhaust stream after fitting the extractors
If you haven't changed anything to do with the intake, then you cannot realistically be changing the intake volume of air. Given the injection instant would not have changed, the AFR that is being relaised by the cylinders will not change. The only conditions that you would see a change at the cylinder is if the exhaust stroke was so choked that you were getting contamination after from the exhaust stroke to the intake stroke, and fitting long tubes has reduced that. If anything, it would go slightly lean. However, if you haven't changed the cat back then I can't see the pipes have had much of an impact, unless they themselves were the restriction (doubtful)
i have already plot the afr error against the maf and then i have copy& paste special ( multiply by%) already twice. but it only changes up to 8000hz. i read that i would have to manually change the upper part of maf. When at wot my afr is spot on but as it hit 9000-9700hz the afr changes to 13.6. so would i be able to do wot runs while plotting afr error against maf. Again i read that i had to do smooth runs while plotting.
Are you using AFR error or fuel trims? If you are in open loop and plotting AFR error you should be able to use all the AFR error data throughout the entire MAF table. End to end. AFR error is AFR error. It doesn't matter that the commanded AFR changes when you enter PE.
Bill Winters
Former owner/builder/tuner of the FarmVette
Out of the LSx tuning game
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