View Full Version : lbz boost tables
dynarex
March 6th, 2007, 09:28 AM
has anyone been able to increase boost on the lbz and not have it fluctuate/hunt up and down under load in 4,5,6,gear?
ive tried and tried and no matter what i cant get the desired and target positions the same-they seem ok under wot and when the converter is unlocked but as soon as it locks up the boost starts ramping up and down about 5psi
lakingslayer
March 6th, 2007, 02:28 PM
Are the vanes changing when this happens and also is the fuel pulse and or pressure changing?
JoshH
March 6th, 2007, 03:39 PM
I've modded mine and I don't notice any surging at any speed. I did change them to drop boost and open the vanes when I'm using light throttle, but it picks up quick when I get on it. I posted a tune in the modded LBZ tune library at the diesel place if you want to copy and paste the tables into your tune to see if it clears up your surging.
dynarex
March 6th, 2007, 10:24 PM
Are the vanes changing when this happens and also is the fuel pulse and or pressure changing?
the vanes are actually changing and so is the fuel pulse
dynarex
March 6th, 2007, 10:24 PM
I've modded mine and I don't notice any surging at any speed. I did change them to drop boost and open the vanes when I'm using light throttle, but it picks up quick when I get on it. I posted a tune in the modded LBZ tune library at the diesel place if you want to copy and paste the tables into your tune to see if it clears up your surging.
ill ck out the tables and try it-thanks
lakingslayer
March 7th, 2007, 09:07 AM
the vanes are actually changing and so is the fuel pulse
Is your fuel pulse changing due to fuel pressure changing or the commanded mm3 changing?
dynarex
March 7th, 2007, 09:43 AM
commanded mm3 is changeing -i think because the target position is diff than the desired boost-so it drops the boost which causes the fuel to frop too
i know its in the target/desired tables because when i change these tables it makes a difference
i need to find a way to "mirror" the desired boost curve and apply it to the target position curve this way they both jive
lakingslayer
March 8th, 2007, 04:25 AM
I don't think the boost vane is changing the fuel volume but I think it's the other way around. The desired boost is only done by the boost sensor which isn't large enough to read say 40psi. I think you may actually have 2 problems here. I'd address the fuel volume problem first. You may be having some torque limiting issues. I wouldn't change the target vane position's in the boost tables unless you are over boosting somewhere and you can't explain it in the desired boost tables. Sometimes changining too many things at once can create weird unexplained problems. I've done it and found that something that didn't seem like it would be a problem was the culprit.
I'd go back and make all the boost tables stock and see if the fuel volume still fluxuates.
Rooky
March 28th, 2007, 01:54 PM
I got my boost up enough for now (need tranny!) just with desired boost and about every table
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