Is This Much VE Change Normal?
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TECH Senior Member
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From: Bethesda, MD
Is This Much VE Change Normal? I was looking back at the total VE change needed to get my LTRIMS to around -2% and I was surprised at the magnitude of the change at low MAP. I know that 400 & 800 rpm changes would be large and that 1200 would need some change, but check out this is sample:
MAP 20
1600 rpm = -45%
2000 rpm = -38%
MAP 30
1200 rpm = -40%
1600 rpm = -30%
2000 rpm = -30%
MAP 40
1200 rpm = -31%
1600 rpm = -17%
2000 rpm = -12%
Interestingly, at high MAP (70+) I actually add a couple percent in this rpm range.
Now my set-up was designed around my previous high stall A4 configuration with my power biased for high rpm:
Cam is on an ICL of 114. Other specs: 228/224 113 XE-R lobes
Headers are 1 7/8" feeding into 3.5" piping
FAST 90mm intake
Heads are MTI heads 5.3 heads lightly milled, but valve reliefs knock my CR back into the low to mid 10.X range.
So is reasonable for my set-up or is this a sympton of a mechanical issue or another tuning issue (e.g. idle air, timing) that is out of whack?
The car idles hot at 850 with a MAP in the high 40s and IAC count in the low 40s. High Octane table is stock M6, either 99 or 00, I forgot which.
MAP 20
1600 rpm = -45%
2000 rpm = -38%
MAP 30
1200 rpm = -40%
1600 rpm = -30%
2000 rpm = -30%
MAP 40
1200 rpm = -31%
1600 rpm = -17%
2000 rpm = -12%
Interestingly, at high MAP (70+) I actually add a couple percent in this rpm range.
Now my set-up was designed around my previous high stall A4 configuration with my power biased for high rpm:
Cam is on an ICL of 114. Other specs: 228/224 113 XE-R lobes
Headers are 1 7/8" feeding into 3.5" piping
FAST 90mm intake
Heads are MTI heads 5.3 heads lightly milled, but valve reliefs knock my CR back into the low to mid 10.X range.
So is reasonable for my set-up or is this a sympton of a mechanical issue or another tuning issue (e.g. idle air, timing) that is out of whack?
The car idles hot at 850 with a MAP in the high 40s and IAC count in the low 40s. High Octane table is stock M6, either 99 or 00, I forgot which.
Yes that is normal with the overlap and the cam at idle it isnt to efficient as an airpump. This causes you to have to drastically cut ve values in order to get the correct LTRIMS and AFR. I would still want to verify your changes with a WB.
15kpa-60 400 rpm-2000 on my cam only G5X4
Code:
34.039302 34.498223 35.115393 35.518927 35.811687 35.930374 35.693001 35.550577 35.392328 35.257817 37.781884 36.144010 36.341821 36.610843 36.871954 37.354612 37.283401 37.077677 37.402087 36.721618 41.738102 40.100228 40.448375 40.875647 41.279181 43.178166 40.503762 39.562182 42.291973 43.660824 45.765532 45.393648 46.026643 46.667550 48.368724 47.577480 45.583546 47.632867 50.797842 53.796655 50.006598 50.797842 51.747334 52.649352 51.652385 53.677969 54.682848 57.618362 59.873407 61.709092
Thread Starter
TECH Senior Member
iTrader: (7)
Joined: Nov 2001
Posts: 9,491
Likes: 1
From: Bethesda, MD
BMF: They get enough hits to measure. I log about 2000 data points each time. For each point, I use excell to round MAP Kpa to the nearest 5. Then for each Kpa point, I look at the data for +/- 100 rpm. So the adjustment for MAP 40 at 1600 rpm is based upon the average of all readings from MAP 37.5 @ 1500 rpm to MAP 42.4 @ 1700 rpm. I also scan the data for any outliers and ignore them.
Yellow: I edit both tables. 95% of the change was done originally with the MAF fail = 0, so that I was on the secondary table. I also copied over the high octane table to the low octane table during that time.
Humpin: I'm not sure how to read that table. LS1Edit uses different numbers in the VE table.
Yellow: I edit both tables. 95% of the change was done originally with the MAF fail = 0, so that I was on the secondary table. I also copied over the high octane table to the low octane table during that time.
Humpin: I'm not sure how to read that table. LS1Edit uses different numbers in the VE table.
Originally Posted by Ragtop 99
BMF: They get enough hits to measure. I log about 2000 data points each time. For each point, I use excell to round MAP Kpa to the nearest 5. Then for each Kpa point, I look at the data for +/- 100 rpm. So the adjustment for MAP 40 at 1600 rpm is based upon the average of all readings from MAP 37.5 @ 1500 rpm to MAP 42.4 @ 1700 rpm. I also scan the data for any outliers and ignore them.
Yellow: I edit both tables. 95% of the change was done originally with the MAF fail = 0, so that I was on the secondary table. I also copied over the high octane table to the low octane table during that time.
Humpin: I'm not sure how to read that table. LS1Edit uses different numbers in the VE table.
Yellow: I edit both tables. 95% of the change was done originally with the MAF fail = 0, so that I was on the secondary table. I also copied over the high octane table to the low octane table during that time.
Humpin: I'm not sure how to read that table. LS1Edit uses different numbers in the VE table.
If I am not mistaken you have to multiply by 30 or 29.96
