Let me start by saying that I don't know! But as an engineer, I would assume that your scenario would be considered a negative deviation because your're adding duty cycle to get to up to target, but still negative with respect to target (your deviation to target is negative). In sure others can confirm/deny. I'm still running an OTS tune, but am starting to poke around in my stock bin and work up the courage to start self tuning.Hi guys
With regards to the P-I-D tables, if my Boost Target (Eg. 23psi) - Boost Actual (Eg. 21psi) = 2psi boost deviation, would it be a positive or negative deviation?
And then with this deviation, would i be looking at the negative or positive axis in the PID tables?
View attachment 59397
When you hit 28.5# is it load actual or load request that's dropping? I'm confused how load actual can drop unless either the throttle plate closes or boost drops?. Perhaps your valvetronic could be closing down to reduce load actual, independant of your throttle plate staying open?Hello fellow DIYer's
I've come across an issue where it seems I have a 28.5# boost limit and I'm wondering how to get past it. I have a 2011 135i with N55E, 98G0B DME. I recently upgraded from a PS2 to a PS750 and am trying to tune to 28# but of course sometimes hit 28.5# and when that happens the DME freaks out, drops load actual a lot which causes the clutches to slip because a much lower torque is sent to the trans. The throttle doesn't close because my boost ceiling is set to 31#. I noticed that in post 252 Steven was able to hold 29# boost without the drama. Does anyone have any idea what could be going on? I know that @mwpa71 (Mark) and @houtan is having the same issue so I know it's not just me, lol.
One thing that was suggested to me was to try raising the max voltage the MAP sensor is seeing from 4.8486 to 5.1, which didn't seem to help.
This is an example log of my issue: https://www.spoolstreet.com/graphs/log-02-27-2024-18-17-11.34176/
Here's a log from @houtan showing the issue: https://www.spoolstreet.com/graphs/log-03-01-2024-21-27-01.34237/
Here's a log from Mark (@mwpa71): https://www.spoolstreet.com/graphs/mark-p750-v2-1-mafless-4th-gear.34232/
Check out the logs, it's load actual and a bunch of other values causing lots of drama, lol.When you hit 28.5# is it load actual or load request that's dropping? I'm confused how load actual can drop unless either the throttle plate closes or boost drops?. Perhaps your valvetronic could be closing down to reduce load actual, independant of your throttle plate staying open?
I'm excited to hear what MHD says about thisWhat's interesting is that 28.5# is 1.965004 bar and 2 bar is 29.007578#. Maybe there's a 2 bar limit in the code even with the N20 TMAP sensor?
I just sent MHD an email describing the problem so hopefully they have some insight to the issue.
We ALL are, lol.I'm excited to hear what MHD says about this