Ive tried my very best to read as much as i can about how to understand and tune these Bosch MED ecu's, but something i cant seem to get a handle of is boost control.
what I seem to get confused on is the PA ratio tables, i understand the aircharge limit tables, however the PA tables confuse me. when i set the aircharge and other turbo ratio tables high, but try and run the PA table at around 3.00 ( car registers 99-97kpa so almost atmosphere), i would think the car would target around 28-30 psi, however in practice, confirming the PA table is the lowest limiter, the car runs near 20psi? am i missing something here? thats 20 COMMAND, not delivered, which they match as expected. no excessive knock, no excessive trimming. am i simply not understanding this correctly?
FK8 turbo control
Re: FK8 turbo control
Three things with pressure ratio tables.
1. The pressure ratio is absolute, so PR 3 is 2 bar of boost at sea level.
2. The pressure ratio uses atmospheric pressure, so absolute boost will drop with atmospheric pressure.
3. The pressure ratio is ratio of pressures before and after the compressor. There will be a drop from the intake to the compressor, rising with air flow. And there will be a drop in pressure from the compressor discharge to the intake manifold, also rising with pressure.
It might be #3 or you might be seeing is another limit, like EGT reduction. If you post the calibration and datalog I can look.
1. The pressure ratio is absolute, so PR 3 is 2 bar of boost at sea level.
2. The pressure ratio uses atmospheric pressure, so absolute boost will drop with atmospheric pressure.
3. The pressure ratio is ratio of pressures before and after the compressor. There will be a drop from the intake to the compressor, rising with air flow. And there will be a drop in pressure from the compressor discharge to the intake manifold, also rising with pressure.
It might be #3 or you might be seeing is another limit, like EGT reduction. If you post the calibration and datalog I can look.
Hondata
Re: FK8 turbo control
heres a short snippet of a log, not a ton to go off of i know. any advice is welcomed!
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Re: FK8 turbo control
Update your software. The additional tables added in the last release may be the cause.
Hondata
Re: FK8 turbo control
will try and report back.
Re: FK8 turbo control
After looking through some defined OEM FK8 ECU reads, it does appear the logic I am missing is the pressure drop tables for the intake and intercooler, with those tables in the equation, the PA tables make much more sense. Is there any development to add those tables into flashpro? speaking with another tuner/mentor who if very familiar with the MED family in the BMW world (also the one who shared the defined fk8 winOLS file with me), he says he often manipulates these tables when tuning those cars.
side note, is there any plan to implement driver requested torque and/or torque delivered logging channels?
side note, is there any plan to implement driver requested torque and/or torque delivered logging channels?
Re: FK8 turbo control
I can add both those tables in.
We can only release channels which are tested, working and consistent. The bosch torque channels will cause a lot of confusion if we release them. The torque is not wheel torque, but a percentage of some arbitrary value.
We can only release channels which are tested, working and consistent. The bosch torque channels will cause a lot of confusion if we release them. The torque is not wheel torque, but a percentage of some arbitrary value.
Hondata
Re: FK8 turbo control
here is the discussion I had with friend about OEM tables missing that he felt would be useful, granted him and I are people who like to deep dive maybe a bit more than the average FlashPro user
So the Bosch names are-
- DPLLKMS: Pressure Drop across intercooler (hPa pressure drop vs MAF pre-IC) at 1000kg/hr or ~500hp of airflow, this is 140hPa.
- DPUPVDMN: pressure drop at air filter (hPa pressure drop vs MAF downstream of compressor) at 1000kg/hr or ~500whp of flow, this is 110hpa. (PEnv_pAirFil_T could also apply)
I would also beg for the following turbo model tables to be exposed, with the ability to change the axis as well:
- KFPVTMSV/ KFPVTMSVFE
- VPVNTVMS/VPVNTVMSFE
- MSNTU, KFMSNWGHL
- KFETAVD and/or ChrSet_etaBoostOpt_M
- KFIPABERG
- KFHATSTS, KFHATS
So the Bosch names are-
- DPLLKMS: Pressure Drop across intercooler (hPa pressure drop vs MAF pre-IC) at 1000kg/hr or ~500hp of airflow, this is 140hPa.
- DPUPVDMN: pressure drop at air filter (hPa pressure drop vs MAF downstream of compressor) at 1000kg/hr or ~500whp of flow, this is 110hpa. (PEnv_pAirFil_T could also apply)
I would also beg for the following turbo model tables to be exposed, with the ability to change the axis as well:
- KFPVTMSV/ KFPVTMSVFE
- VPVNTVMS/VPVNTVMSFE
- MSNTU, KFMSNWGHL
- KFETAVD and/or ChrSet_etaBoostOpt_M
- KFIPABERG
- KFHATSTS, KFHATS
Re: FK8 turbo control
The intercooler and air filter tables have been added. Using g/s you will have to divide the kg/hr by 3.6 Just promise that you will not just zero the tables...
We will look at adding the other tables, but I would need to know why people need to change tables like the internal EGR factors.
We will look at adding the other tables, but I would need to know why people need to change tables like the internal EGR factors.
Hondata
Re: FK8 turbo control
Yes haha i will not simply be zeroing the tables, I actually have pretty much every single commonly purchased intercooler on the market already equipped with sensor bungs so ill likely be compiling some pressure drop and air temp data in the coming weeks. Calculating drop on the filters may be more of a task. My R&D vehicle is just at the 500whp range with PRL's P700 and all bolt ons from MAPerformance.
I will drop a snippet of my conversation with tuner friend/mentor/colleague in the morning about the other tables, however he mentioned the EGR tables probably only really be applicable to people running drastically larger turbos than factory. A TL;DR of the conversation is, the more influence you have over the "internal turbo model" the better you can control it, or more so the ecu can. We both appreciate your willingness and swift action making these changes! shows how dedicated you are.
I will drop a snippet of my conversation with tuner friend/mentor/colleague in the morning about the other tables, however he mentioned the EGR tables probably only really be applicable to people running drastically larger turbos than factory. A TL;DR of the conversation is, the more influence you have over the "internal turbo model" the better you can control it, or more so the ecu can. We both appreciate your willingness and swift action making these changes! shows how dedicated you are.
Re: FK8 turbo control
conversation at hand
The ultimate desire is to have the turbine, compressor and wastegate flow models match reality, and with bigger turbos/more mass flow than is scaled for in the factory turbo models, you end up being at the maximum of the table axis and zdata… but in most cases with stock frame turbo upgrades you could get away with just manipulating the electric wgdc position tables to achieve the desired outcome. However, that effectively means the ecu isn’t accounting or adjusting for anything once you’ve exceeded the maps’ maximums, and you’re just relying on the ‘knowledge’ of what positions result in the X boost output in those specific conditions. It might take a bit more work in the beginning and go through the model and adjust it to match the specific turbo, but once that’s done it becomes so much easier to dial in the tuning and be comfortable sending it out blindly to any car in any environment.
About the internal EGR factor table: those probably wouldn’t be included in the “beg for them” category, but they can cause fresh air/load calculation challenges when running much bigger turbos with dramatically less backpressures at the same rpm vs cam angle, especially if the calculated EGTs aren’t adjusted as well. These would be towards the final phases of dialing in big turbos though, and probably not considered critical
The ultimate desire is to have the turbine, compressor and wastegate flow models match reality, and with bigger turbos/more mass flow than is scaled for in the factory turbo models, you end up being at the maximum of the table axis and zdata… but in most cases with stock frame turbo upgrades you could get away with just manipulating the electric wgdc position tables to achieve the desired outcome. However, that effectively means the ecu isn’t accounting or adjusting for anything once you’ve exceeded the maps’ maximums, and you’re just relying on the ‘knowledge’ of what positions result in the X boost output in those specific conditions. It might take a bit more work in the beginning and go through the model and adjust it to match the specific turbo, but once that’s done it becomes so much easier to dial in the tuning and be comfortable sending it out blindly to any car in any environment.
About the internal EGR factor table: those probably wouldn’t be included in the “beg for them” category, but they can cause fresh air/load calculation challenges when running much bigger turbos with dramatically less backpressures at the same rpm vs cam angle, especially if the calculated EGTs aren’t adjusted as well. These would be towards the final phases of dialing in big turbos though, and probably not considered critical
Re: FK8 turbo control
Hello klarkin7, I am currently tuning a couple FL5s using winols. I have FK8 and FL5 A2Ls but not a funktionsrahmen. Did you interpret MSNTU as Phi factor, or swallowing capacity of the turbine housing?
Did you have success fixing the turbocharger model? I´m about to tune a car with a PRL700 and it seems the wastegate is bigger, so I assume fixing at least KFHATSTS should be necessary for proper boost control.
Did you have success fixing the turbocharger model? I´m about to tune a car with a PRL700 and it seems the wastegate is bigger, so I assume fixing at least KFHATSTS should be necessary for proper boost control.