Printable View
[PID.2360] - Is there a scanner limitation to 37psi absolute for this pid? For example, if I'm holding 22psig with one tune, and I up the pressure RPM factor a bit, the desired boost value doesn't change, but the car runs more boost. If it's a scanner limitation, I'm okay i think. If it's not, I need to figure out what i need to change that's holding it down. 3-bar maps installed and calibrated in the tune by the ways.
Thanks for any help or suggestions.
Anyone? Does anyone see greater than 37psi absolute for this pid?
PID.2360 limits at 255 kpa as far as I know. PID.2338 Boost lo-res, seems to read up to 512 kpa. Remember to subtract baro pressure to get a more accurate boost reading. I think it's PID.51 but it may be a sensor, you'll have to check.
boost lo res - baro which is pid51.
on a failing wastegate i saw it spike 40 on a gt3076r so the map sensor depicts the limit. we had 4 bars installed.
Thanks for your reply - PID 2360 is desired boost, while PID2338 is measured from the map sensor. So if PID2360 is limited to 255kpa no matter what the tune looks like, will the controller fight the WGDC down to 22psi? I'm having a challenge fine tuning the boost to 24 psi, it seems like commanding 22 and tailoring the duty cycle to it works great, but going over, i can't get it consistent from day to day. Do I have to set all the proportional/derivative/integral to zero?Quote:
Originally Posted by COSky
Anything running outside the measurable parameters will be uncontrolled, and can vary greatly with temperature, altitude, and humidity amongst other environmental changes.
Think about a thermometer that only measures to the freezing point of water. You can still boil water if you so choose, however, you and the stove will have no idea at which temperature the water began to boil. With low enough atmospheric pressure you can boil water at 30F and you'd be able to see this on your thermometer, but a majority of the time you'll have no idea when the water began to boil.
Now if you run outside the control window you can achieve your desired result but there will be a ton of trial and error. I recommend using a parameter that can measure your desired setting, and then adjusting parameters that have the range to control components required to reach that setting. That said*using the WG to control boost works fine as long as you know what DC percentage achieves your desired level. In order to do that you will need to accurately measure boost. Using DAL, WGDC, optimum torque, and MAF tables, I've had no problem commanding and controlling boost exceeding the limits of the desired boost PID. Check out CSSOBs links he has a ton of info in them that helps with how to work out all the relationships.
[pid.2338.kpa]-[pid.51.kpa]
this is all you will need.
then when you set up the histogram tell it the units are psi and it will auto convert for you 8)
i dont use that though since most i see are around 102kpa consistent baro i use the converter to tell me what 24 psi is in uncorrected kpa and just log the boost lo res by itself and shoot for the target uncorrected kpa value.
if you log only boost lo res 267kpa is 24 psi boost and 255 is 23 psi boost. anything higher than 267 needs lowering and anything bellow 255 need increasing 8)
What if the pcm is pulling back WGDC? For example, like you said, I want 24psi flat, and on my set up it takes ~74-76% WGDC to get there, then after a couple pulls, It's winding back WGDC to 72% in some cases - giving me ~22psi.
Also, as i mentioned, my car has the GMS1 3-bar maps, calibated properly, so I'm not running anywhere near outside what my sensors can measure. My boost limit is set at 26 psi (275kpa), and my pressure ratio table is also set to 2.75 for now (which realistically, being in the desired boost section of the torquemanagement, should be commanding 26 psi lol).
I just feel like the problem is the desired boost - because if I dial everything back to run 22 psi, it seems consistent and happy. I'll have to upload a tune when i get home to see if I'm missing something obvious.
if it keeps roping back then its tune related weather you missed a section to change or the tune corrupted (which happens a lot on the lnf) idk. a turbocharger doesnt make a high pressure run then dial back and then do it all over again.
check your bov for proper function and your wastegate but other than that mechanically speaking there isnt much.
Quote:
Originally Posted by oldskool
What's your pressure limit set at?
should look like that or you will be hit a cap that the ecu uses to prevent shaft overspeed on the oem turbo
My pressure limit is set to 275kpa. Cobaltssoverbooster, my tables definitely do not look like that - I'm attaching my current tune (zfr turbo).
I guess I was hopeful that the factory control would work above 22psi, but you're suggesting that I should defeat the pressure limit and the pressure rpm factor to run directly from the WGDC table? If I do that, there will be no altitude or temperature compensation for boost right? It is what it when baro or weather changes?
Thanks for the advice and help guys - I never had a reason or desire to run over 22psi before so I never really explored it.
there is only 1 way to tune this motor in my eyes and that is to disable all correction factors and limits. tune the car for your specific set up and then when your all done apply the limits for protection 1 table at a time.
oh under the 3 bar map settings you missed the setting where you copy the boost sensor p0236 range high into the map sensor p0106 range high.
I would suggest increasing the pressure limit first and see where that gets you. Good luck man.