Sorry about the delayed reply. No not directed at you at all. Your info has been great. Thanks again for your findings so far. I hope soon I'll get a chance to work through the torque tables one-by-one. I'll wait a bit longer for an 8HP flash first so I don't need to under-report torque to get under TCU limits. I've been trying to resist temptation to modify the car until the TCU flash comes as the 440nm 3rd gear limit is atrocious. I don't mind the 400nm 6th limit as I don't really drive flat out in 6th anyway. I'm happy with the stock TCU calibration so I'll literally just change the 3rd gear limit to 500nm and 6th to 480nm and flash it back on.So not sure if your frustration is directed at me but I think I have been sharing pretty openly. I can't just post every revision of my xdf and bin because a) there are people like EMP out there and b) this is dev work and much is untested.
For the torque stuff I am now running 100% stock load to torque tables. The tq limiter tables - KL_MDMAX, KL_MDKMX_ATL_***, KF_MDKMAX_GANG_MOD1, and KF_MDKMAX_GANG_MOD2 are raised. Additionally, some codewords for various tq intervention functions are disabled.
It is hard to test individual parameter changes on the street with a flash required for each iteration. So while I agree that it is best to only change what absoluteluy is required it isn't necessarily always practical. At least until real-time tuning is released.
For the DP you should look at KF_AUSY_TURB - Flow characteristic turbine.
It limits torque (reducing timing and/or load target). I'd prefer not to disable the intervention just in case the transmission requests torque limitation for other reasons (overtemp, slip or any other reason) that I do want the intervention to work. Also I don't have any time at the moment so happy to wait for XHP. I haven't put the downpipe in yet and undecided what I'm doing about the turbo. I was so, so disappointed when I found out my car was PWG (2014 F11 LCI 535i). It really messed up my plans for the car.Does going over the limit put the trans in limp mode or just trigger a torque invetervention request? I believe I have the code words to disable the trans protection intervention modes in the DME but if the trans goes into limp that won’t be enough.
Thanks. Yeah I should start thinking about getting it done because damn it's slow compared to the 335i I had. The issue is I don't really like ANY of the aftermarket turbos out there. I'm tempted to just get a used EWG core and get my compressor housing machined for it.I would think that slip or overtemp would cause limp regardless. I just disable the torque interventions for trans protection (and a few others). If you wanted to try it let me know. I know it works on DCT but curious to see how it works on the 8 speed.
EWG compressor wheel is 5mm bigger which is a fair bit. PS2 is the other extreme and a bit too big and I don't like the clipped turbine wheel.I think the main benefit of the EWG as far as tuning is concerned is the larger turbine housing. EWG is nice but if they were the same size I don’t think it would make much difference. How crazy do you want to go with it? PS2 makes good power if you want to stay stock frame. If you want to go to a standard aftermarket turbo you have Motiv and Speedtech among others making bottom mount kits. Basically I’m saying the PWG isn’t really a disadvantage unless your plan was to stay stock turbo.
The EWG dump pipe flange and outlet area is bigger but I don't think that'd make a difference. I think it's really the bigger comp wheel where the performance difference lies. I don't want or need the power the PS2 is capable of and a slightly smaller version of both wheels and a proper Garrett-style un-clipped turbine should give a decent response improvement over the PS2.The turbine housing on the EWG is larger too was my understanding.
The PS2 has been pretty well proven on the N55. I wouldn’t hesitate to recommend one. I’m pushing it’s limit now on my car though and am trying to figure out where to go next. Need to wait for boost season here in AZ and see if I’m happy with this turbo at its max in good weather. Honestly, I’m pretty sure I will end up upgrading regardless just to be able to continue the tuning development I’ve been working on.
It would be fine if I wanted to push it to the limit but I don't. I don't need the huge compressor, I don't need the huge turbine and I don't need it clipped. It's a verrry nice car and I don't want to spoil it with compromises. I only want to run 14psi flat with absolute best possible response.I don’t think a clipped turbine is a bad thing in this application. It spools fine and makes more power literally everywhere. I think a lot of people take Garetts statement that you should never clip a turbine wheel a little too seriously.
Always impressed. How much time does it take you to wade through all of this?Haven’t posted an update in a while.
Dug into the compressor characteristic / turbine power calculations a bit and put together this. Excuse the MSPaint skills ....
View attachment 17199
KW value from compressor characteristic table corrected with PID based on boost error and exhaust target flow then goes into exhaust flow, temp, and pressure models to get a WG/Turbine distribution factor. This distribution factor is turned into WGDC with the WG Position model and then the spring in the actuator is compensated for with the WGFEDER table. This “base WGDC” value is then blended with the feed forward tables. That value is summed with the altitude correction, pressure dynamics correction, and offset by gear. This value goes into the adaption function, a damping function and is then added to the output of the I controller. Note, this is a second I controller, the first adds kW to the turbine power value and uses exhaust gas mass flow. The I controller most are familiar with is the second one which adds or subtracts WGDC and uses mass airflow and boost error as axes. There are various limiters, most of which are raised in the stock M2 BIN. For the most part I have been successful leaving most of the PID set as in the M2 bin and modifying/rescaling just the compressor characteristic table with the P, I, and D tables zero’d to get boost close to target. Then turning PID back on. I found one of what I thought was my best revisions made about 8psi less with PID turned off. Obviously the compressor table wasn’t right and PID was just adding a ton. Would really be nice to be able to log the individual PID terms like N54.
A couple more notes. WGDC Base log channel appears to be the output of the compressor characteristic table in kW. I don’t believe it is WGDC.
I’m not sure what WGDC after PID is.
In my bin I’ve rescaled the WG position model to a linear 1-100% and zero’d the WGFEDER table (how an EWG car is). I know this is incorrect as the PWG model is not linear because the WGDC does not result in a linear change in WG position but I personally have found it easier to tune this way.
There’s a lot more I’m leaving out I’m sure but just wanted to spark up the PID tuning discussion again.
Spool is great, boost follows target no problem, but it still spikes a few PSI post shift on DCT and AT cars. The WG tables for post shift are all only active on MT. @LamboLover you mentioned your custom boost control strategy on GTR resolves a similar issue. Any insight?