2013 Cruze boost limit

[oldskool]

Hey guys - I'm for some reason not able to push past 17 psi on my cruze (216kpa). Mods are catless dp and mid pipe, zzp FMIC and intake pipe. I've tuned out the trims on the maf for the intake, and as far as I can tell taken care of all the tables limiting boost, yet i can't get a commanded higher than 215-216kpa. Could someone take a look at let me know if I'm missing something obvious? FWIW, I'm trying to get a stable 19-20 psi. Thanks!

[oldskool]

I'm stumped here guys - Latest file is attached, as you can see i pulled out all the stops, and it only commanded 212kpa today. It was a bit cooler out, and it peaked 204ftlbs engine torque, but I'm not getting anywhere near the boost limit, and based on what Chris posted in the longer Cruze tuning thread, I should be holding the wastegate closed to my boost limit with these settings. Please advise if you have any ideas.

[rcmn0022]

Some tables that I have changed to gain more boost(that you have not changed as much as I have);
- Turbocharger Knock Airmass Limit
- Turbocharger Base DC
- Allowed Pressure Delta Factor

[oldskool]

You looked at the second file right? I'll have to check the knock airmass table and the pressure delta table, the duty cycle table shouldn't affect commanded boost, it just needs to be adjusted if the map-high res is not keeping up with commanded boost. For what it's worth, I'm not getting anywhere near the 0.95 grams/cyl that's in the knock airmass table.

Thanks for looking, when I get a chance, I'll make adjustments and check it out.

[rcmn0022]

By adding more duty cycle in, you are telling the ecu to start with more boost and will allow it to get to its final value more quickly. I ran into the same problem and someone else was kind enough to help me out with the same suggestion. I have found that the faster the boost builds, the more likely you are to reach the commanded boost values.

If you want to read up on how PID controllers work then you can start playing with the PID controls for boost control.
Essentially they break down as follows P is present error, I is past error, and D is future error. I can't remember off hand which of those I have played with to get faster boost.

[oldskool]

I appreciate what you are saying, but the car is achieving the commanded boost. My problem is that it is not commanding high enough boost. Adjusting the WGDC table too high will just result in overshoot of the commanded value until the controller learns back. For example, my last log commanded 212kpa, and it pretty much hovered at 210-215kpa for the whole pull. To restate my problem, the car should, based on Chris's initial explanation, be commanding my current boost limit in the torque management -> turbocharger section, but it's commanding significantly below that.

If I get to a point where the actual boost is lower than the commanded, i'll certainly take advantage of the WGDC table.

By adding more duty cycle in, you are telling the ecu to start with more boost and will allow it to get to its final value more quickly. I ran into the same problem and someone else was kind enough to help me out with the same suggestion. I have found that the faster the boost builds, the more likely you are to reach the commanded boost values.

If you want to read up on how PID controllers work then you can start playing with the PID controls for boost control.
Essentially they break down as follows P is present error, I is past error, and D is future error. I can't remember off hand which of those I have played with to get faster boost.

[rcmn0022]

Would it be possible for you to upload a log of a run from your car?

I know that I was able to build way more boost after my buddy and I installed custom hard pipes for the intercooler piping.
After my hard pipes, I started running about 10-15% less MAF for the same amount of boost. There is a lot of movement allowed on the factory couplers onto the stock intercooler. These couplers were a great source of boost leakage, and you also lose some boost when you inflate the rubber. Here is a video of a dyno run on stock boost levels of the rubber tubes.


You may be hitting a limit in regards to mass air flow. I cant think of what limit it might be, I'll have to update you later on what it might be.

[oldskool]

The most recent log I have is attached. Looks like 16.5psi commanded and achieved, and 18.3 peak MAF lbs/min. Looking at it closely I may have hit my airmass limit of 0.85g/cyl, but only for a second or so, and it didn't command higher boost before that or after that.

[rcmn0022]

Another thing that you can try is this cheap diy mod. Bypassing the bypass valve solenoid by MPFab

I will be looking over your log later today.

[rcmn0022]

After completing the posted DIY mod, I'm making around 230kPa at the MAP but my commanded is only 212-213kPa

I believe the limit of the sensor that is referenced for commanded boost is around that range so it won't let it go any higher. If I were you, I would add in some more duty cycle to the wastegate table and you should be able to get more boost.

[oldskool]

http://www.hptuners.com/forum/showth...l=1#post301089

Please see the above post from Chris@HPTuners. That's all I want for the car - there should be no need for hardware fooling or boosting over commanded. My stock map sensor linear is 312kpa, and the offset is -11kpa, indicating that it's a 300kpa absolute capable sensor - it should be able to read up to 30psi boost, and i'm only asking for it to command 19psi.

[rcmn0022]

http://www.hptuners.com/forum/showth...l=1#post301089

Please see the above post from Chris@HPTuners. That's all I want for the car - there should be no need for hardware fooling or boosting over commanded. My stock map sensor linear is 312kpa, and the offset is -11kpa, indicating that it's a 300kpa absolute capable sensor - it should be able to read up to 30psi boost, and i'm only asking for it to command 19psi.

I'm not saying that the MAP sensor is maxed out, I was trying to say that the "commanded boost signal" maxes out and doesn't seem to go any higher. By adding in some more duty cycle to the table I mentioned earlier, you can add in more boost to the car.

I also only mentioned that DIY mod since it makes a world of a difference in the way the Sonic responds. I hardly doubt that they changed the lines for this part to not allow this mod on the Cruze. I never said that you had to do the mod at all. You should be able to get your goal with adding into the duty cycle table that I mentioned before.

[oldskool]

I'm not trying to sound combative or contradictory, but why would the developers tell us how to do things the right way, and then it doesn't work? Admittedly, I haven't messed with it since December, and I need to raise the knock airmass and delta factor to completely mimic what Chris laid out. The only reason the commanded boost would max out is if there is a table or parameter missing from what we can modify. If after adjusting those last two tables, I cannot get the commanded boost where I want it, I'll just email support directly with logs and the tune. I don't like taking shortcuts in the tune.

I'm not saying that the MAP sensor is maxed out, I was trying to say that the "commanded boost signal" maxes out and doesn't seem to go any higher. By adding in some more duty cycle to the table I mentioned earlier, you can add in more boost to the car.

I also only mentioned that DIY mod since it makes a world of a difference in the way the Sonic responds. I hardly doubt that they changed the lines for this part to not allow this mod on the Cruze. I never said that you had to do the mod at all. You should be able to get your goal with adding into the duty cycle table that I mentioned before.

[cobaltssoverbooster]

Lsj and lnf are missing tables. It's not hptuners problem. Fully unlocking an ecu makes it a copyright infringement by vehicle manufacture and ecu manufacture. It is a given all ecotec motors will only be unlocking the most needed tables. Base calibration data and wot control. If you want 100% access I don't think you will find it outside of full standalone setups. Sorry to ruin any hopes you guys may have.

[oldskool]

Ummmm, where did i ever say I wanted 100% access? All I said was if I follow what Chris himself said to do to achieve a commanded boost limit, and i do NOT achieve that limit, I will contact support. NBD...

Lsj and lnf are missing tables. It's not hptuners problem. Fully unlocking an ecu makes it a copyright infringement by vehicle manufacture and ecu manufacture. It is a given all ecotec motors will only be unlocking the most needed tables. Base calibration data and wot control. If you want 100% access I don't think you will find it outside of full standalone setups. Sorry to ruin any hopes you guys may have.

[cobaltssoverbooster]

The only reason the commanded boost would max out is if there is a table or parameter missing from what we can modify.

No you did not just adding to this statement that you guys missing tables is highly guaranteed.

Not trying to ruffle your feathers.

[Chris@HPTuners]

when I did my testing I set the knock airmass to 2.0 above 4000rpm and used the max boost table at 240kpa. My desired boost sits solid at 240kpa from 4000rpm onwards.

I think the knock airmass table is limiting you.

[Gh0st]

By adding more duty cycle in, you are telling the ecu to start with more boost and will allow it to get to its final value more quickly. I ran into the same problem and someone else was kind enough to help me out with the same suggestion. I have found that the faster the boost builds, the more likely you are to reach the commanded boost values.

If you want to read up on how PID controllers work then you can start playing with the PID controls for boost control.
Essentially they break down as follows P is present error, I is past error, and D is future error. I can't remember off hand which of those I have played with to get faster boost.

Yeah, this was the key to getting me to my max boost limit back when I was messing around last summer. Leaving the default values I would never get past 17psi

when I did my testing I set the knock airmass to 2.0 above 4000rpm and used the max boost table at 240kpa. My desired boost sits solid at 240kpa from 4000rpm onwards.

I think the knock airmass table is limiting you.

Why would that be though? If you're not hitting 1g/cyl, why would it be limiting him? Is there some different calculation going on here?

[Chris@HPTuners]

yes, after looking into the spark retard value used for the axis on the table its not just the knock retard. It's more than that *sigh*

Timing Retard Axis = (Base Spark - HighOctaneSpark) + IATSpark(limited to 0) + ECTSpark(limited to 0) + FlexFuelSpark - KR

Base Spark = the current base spark lookup from High and Low Octane tables
HighOctaneSpark = lookup from high octane spark table

So basically it's the difference between the current spark and the high octane spark (a negative number) plus the IAT, ECT and FF spark (all negative as well) minus the current KR value (a positive number, hence the minus).

Hope that helps,

Chris...

[oldskool]

Thank you so much for looking and posting!! I was hoping you'd chime in adn confirm that one of the parameters in my tune was not "all in". When the weather cooperates, I'll give that a shot.

when I did my testing I set the knock airmass to 2.0 above 4000rpm and used the max boost table at 240kpa. My desired boost sits solid at 240kpa from 4000rpm onwards.

I think the knock airmass table is limiting you.