Cruze 1.4t won't hold boost past 5000rpm

[hippotuning]

Have a Cruze tuned up on E85 with a 3.3 bar 13+ Cruze MAP. Has your standard kn intake, CXracing intercooler, ported intake and E85 conversion with flex fuel sensor. Made 202whp 271wq at 21.5psi on the dyno but no matter what I do the boost drops from 21 at 5000rpm to 17psi at the redline. Turned up the pressure rato max to 2.6s7, driver demand tables to 300 on the bottom row, knock airmass to 3. overspeed limit to 1.1, boost max to 255kpa, torque values up, etc. Commanded boost stays at 255 but the boost will not stay consistent any ideas?

[cobaltssoverbooster]

Pid tables

[buickz]

Turbocharger Base DC is what I have been using to ramp out boost in the higher RPM. Might try upping the values in the lower row to see if that makes any difference.

[Terminator2]

Have a Cruze tuned up on E85 with a 3.3 bar 13+ Cruze MAP. Has your standard kn intake, CXracing intercooler, ported intake and E85 conversion with flex fuel sensor. Made 202whp 271wq at 21.5psi on the dyno but no matter what I do the boost drops from 21 at 5000rpm to 17psi at the redline. Turned up the pressure rato max to 2.6s7, driver demand tables to 300 on the bottom row, knock airmass to 3. overspeed limit to 1.1, boost max to 255kpa, torque values up, etc. Commanded boost stays at 255 but the boost will not stay consistent any ideas?

You are out of turbo so to speak most likely.

[hippotuning]

Do you mean post logs of the pid's cobaltssoverbooster?

Others are able to have consistent boost at similar power levels so I'm confident it can do it.

[cobaltssoverbooster]

no i mean pid tables are calculated using software from gm. they aren't mapped to be super responsive. Read the wikipedia listing for pid controllers if you don't already understand them. there is a good section in there on tuning a pid system controller.
As for why i mention that feature, the pid control up top has just enough error in it to not allow the turbocharger to loose pressure before it physically cant flow enough air. in better words if your commanding 23 at 5500 there is enough error in the controller to let it drop to 21 before it makes a correction. in all reality the turbo could be capable of boosting 23 up to, for example only, about 5800 rpm where it then physically runs out of steam. properly tuning those tables along with keeping everything smooth and consistent will net you higher boost in the upper rpm range where the turbochargers tend to not keep up with the required airflow to maintain high boost pressure.

in the lnf people have gained an additional 400 rpm of full boost pressure on top of where they landed with the gmpp values. it helps widen the power band and kick boost on faster without over boosting. check out the post for the lnf to help shed more light on the pid systems.

[codename Bil Doe]

http://www.hptuners.com/forum/showth...LNF-PID-Tables