2nd Gen Chevy Cruze Boost Limiting

I had a 2015 Chevy Cruze and followed the forums to increase boost and maintain that boost at higher rpms which worked out well. I however made the same changes to the pressure delta, knock air mass and turbo overspeed charts to my new 2017 Chevy Cruze but I cant seem to get the cylinder air mass to reach what is being commanded in the knock air mass and cannot reach my boost max limit set at 240kpa (maxes around 215 during wot and tappers down to 190 kpa). Anyone perhaps might have any ideas on what else could possibly be limiting boost/air mass? Thanks

You may have something in Torque Management reducing torque (reducing boost). Make sure everything is unlocked within reason, you may want to limit torque below 3,000 rpm, but above this it should be 6,000 lb-ft or whatever that make is.

I'm having the same issue and at this point I believe there's a table that has yet to be unlocked because I've gone to the extent of maxing out every table and I'm getting this surging of boost at only 142 kpa peak.

All of these tables are limited to 1190 lb/hr airflow. I have suspicion that there's a cutoff to airflow possible shutting the throttle blade. I'm not seeing it close in the scanner but I'm hearing the bov. I'm not sure what else to do.

You should post up a log with that file.

Are you seeing any throttle closure when you are hitting your max boost? Or seeing any KR at that limit?

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Originally Posted by 5banger

All of these tables are limited to 1190 lb/hr airflow. I have suspicion that there's a cutoff to airflow possible shutting the throttle blade. I'm not seeing it close in the scanner but I'm hearing the bov. I'm not sure what else to do.

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Try to scan both ETC and TPS, see if ETC is closing. Also, are you logging KR? I think there is a KR boost reducing function in there, probably under spark>retard tab. In addition, add DC boost solenoid to see if that is being modulated.

There are two ways to view throttle, TPS and ETC. ETC is the throttle plate position, TPS is the gas pedal position. On my E78 1.4T, there can be huge differences between them, like I give 1/2 throttle, the ETC goes full open then the car manages max boost based on my "torque demand".

http://www.hptuners.com/forum/showth...ottle-Position

I'm scanning all of them and the dc boost solenoid shows 0% at wot and randomly 100% and other random percentages all over the graph. It makes huge jumps in percentages. Tps and etc both show 82% and 100% respectively without fluctuation at wot. And I'm seeing zero knock.

Reference the scan screenshot below, to see the expected behavior of the Boost Sol % (grey) and Boost PSI (pink); example is a 1.4T LUV E78. I would say your Boost Sol % is indicated your problem, you may want to do a quick mechanical once over of the wastegate and actuator. Otherwise, there may be something in the calibration preventing boost still.

http://i.imgur.com/xJEdjdI.jpg

Yeah this ecm e80a is weird because no matter what i change wg duty cycle, cylinder air mass, driver demand, even some of the settings under engine diag airflow for airflow correlation and under/overboost diag that may potentially put a limit on the max boost. But no matter what i do the cylinder airmass will not reach my commanded. Only other thing i may try is running no air filter to see if maybe the air filter and or airflow induction system is more restrictive not allowing the airflow at higher ranges

Unless I am blind lol I still have yet to see a log posted in this thread? Logging all the usual stuff and then some. We might be of a lot more help on your issue with a log file. ;)

Log

Funny 4 6 8 all the same we all fight same issues. My 2016 vsport same thing closing throttle to limit boost / torque. I did Log my delivered torque and once it crosses engine torque max then it closes some or if crosses boost Torque limit and I have the tables higher at that rpm where it shows the smaller value in log so something else is getting in the way for sure so going to follow along here as many with lf3 and lf4 seem to fight this too. Strange thing is my 2013 ats was easy to fix when closed throttle or limited boost raise knock air mass table and maybe lower the D.C. Boost table where boost takes off it was a balance but none of that is working on this vsport.

some high boost up 1.4t 2nd solution

I have chalked mine up to the turbo being maxed on my le2 with the stock intercooler. Plus with the wastegate closed until peak boost is reached makes the engine unbelievably lousy due to the turbo being sized for max torque under 2500 rpm on a 1.4L. It really needs a bigger intercooler and turbo.

Shit i forgot i made this. It was the virtual torque tables that limited me from making more boost. I get 20psi by 4k and it drops to 17psi at redline with the virtual torque changes

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Originally Posted by TCSS07

Shit i forgot i made this. It was the virtual torque tables that limited me from making more boost. I get 20psi by 4k and it drops to 17psi at redline with the virtual torque changes

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Can you post up what you ended up with?

here ya go. i ran maf only so i only adjusted the maf portion of the vt calculations. i did it at the actual tables rather then using the coefficients charts.

notes in file - 300% zoom is easier to read as they are screen shots
Attachment 95214

this may be a dumb question but I notice in your bottom chart you have a "PRatio math". Is that a conversion to the pressure ratios in the base dc table? and if so could you share what equation you have to calculate that? Im currently trying to dial in my dc table because I keep getting annoying partial throttle surging from 3200-4200 rpm and my assumption is the elevated boost over desired that is occurring. I just can't accurately figure out what cells to adjust other than just guessing the area.

(map kpa + 101.325) /101.325 = manifold pr atmospheric base
*if your around sea level

or you can go by sensor readings
(map kpa + baro kpa) baro kp = manifold pr sensor base