SUPRA ULTIMATE B58 JB4 GUIDE AND LOG REVIEW (V1)

[ColonelAdama]

Just making sure you are saying that it helps smooth out the boost to keep the throttle closures to a minimum or do you know what they changed to help with the throttle closures?

Yes, correct. At full load, the B58 is designed to use wastegate control for keeping boost on target. The throttle only intervenes when the wastegate is not tuned properly to keep boost under target. Its ok to ride the throttle a little, I usually say if throttle stays >80% during the pull, its fine and you won't feel it.

On MTs, WGDC needs to be set much lower than an AT car and it was previously capped by the older firmware at 29 minimum. I still haven't figured out why it needs to be lower on an MT.

330e has the same issue, as do some LCI bimmers. Hopefully @razorlab can make sense of it ? there are so many tables in the DME just for compressor/turbine power/etc that go into the WGDC output. then the DME has its own internal PID for WGDC, as does the JB4 that is stacked to it. Its quite a cluster.

But yeah, tldr is: JB4 needs more aggressive WGDC control on MTs(and some ATs) to keep boost under target otherwise throttle kicks in and ruins drivability.

MT pull for example -credit to @RyanA90
https://datazap.me/u/coloneladama/l...-2-3-4-8-9-11-20-25-26-27-28-29&zoom=983-1042

WGDC needing to get down below 29 wouldn't be possible on older than V24 firmware (which on this car is every RPM below 5k...)

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[Cfdproductions]

Yes, correct. At full load, the B58 is designed to use wastegate control for keeping boost on target. The throttle only intervenes when the wastegate is not tuned properly to keep boost under target. Its ok to ride the throttle a little, I usually say if throttle stays >80% during the pull, its fine and you won't feel it.

On MTs, WGDC needs to be set much lower than an AT car and it was previously capped by the older firmware at 29 minimum. I still haven't figured out why it needs to be lower on an MT.

330e has the same issue, as do some LCI bimmers. Hopefully @razorlab can make sense of it ? there are so many tables in the DME just for compressor/turbine power/etc that go into the WGDC output. then the DME has its own internal PID for WGDC, as does the JB4 that is stacked to it. Its quite a cluster.

But yeah, tldr is: JB4 needs more aggressive WGDC control on MTs to keep boost under target otherwise throttle kicks in and ruins drivability.

MT pull for example -credit to @RyanA90
https://datazap.me/u/coloneladama/l...=1-2-3-4-8-11-20-25-26-27-28-29&zoom=983-1042

WGDC needing to get down below 20 wouldn't be possible on older than V24 firmware

any idea if i load up the new firmware will it delete my current revision or is it going to keep it and i may have to adjust some things?

 

[ColonelAdama]

any idea if i load up the new firmware will it delete my current revision or is it going to keep it and i may have to adjust some things?

It should keep your revision but you can also create backups in the app with "save config" under user adjustment.

 

[razorlab]

Throttle closes based on going over target load, not boosty. Sometimes, going over boost target causes it to also go over load target. Remember, it's load/torque based.

 

[ColonelAdama]

Throttle closes based on going over target load, not boosty. Remember, it's load/torque based.

Yup, very true. Just in the case of JB4 - doesn't control timing. So our only way to keep load under target is with WGDC and boost.

 

[razorlab]

Yup, very true. Just in the case of JB4 - doesn't control timing. So our only way to keep load under target is with WGDC and boost.

Yea, and your are probably fighting the boost PID control the whole time.

WGDC with the oem strategy is based on the Compressor table, which changes the distribution factor, which changes what cells the DME follows in the Feed-Forward table, then the PID control enters the room based on boost target +/-, which is derived from torque/load and Boost Setpoint via the Pressure Ratio tables. The P-Gain can change the Compressor table dynamically as well and is one of the faster PID controllers.

 

[ColonelAdama]

Yea, and your are probably fighting the boost PID control the whole time.

I figured as such. Thanks for sharing this info. I know you had checked cylinder fill/load tables of MT vs AT and saw no difference, but have you looked at the feed forward / PID stuff comparing the two yet? Specifically the tables you shared.

Also hopes this shows anyone reading the thread how truly simple JB4 tuning is compared to a proper calibration ?

 

[razorlab]

I know you had checked cylinder fill/load tables of MT vs AT and saw no difference, but have you looked at the feed forward / PID stuff comparing the two yet? Specifically the tables you shared.

All the same 2021+

 

[Cfdproductions]

can anyone explain why my trims are at 49 if i roll into 3rd gear but as soon as i hard shift 4th it will drop into the 30s BUT when i start in 2nd and hard shift into 3rd my trims in 3rd look great and are usually low 40s? It seems that it is fairly consistent with doing it when the throttle chopping occurs and it typically only happens in whatever gear i first start the pull in.

 

[ColonelAdama]

can anyone explain why my trims are at 49 if i roll into 3rd gear but as soon as i hard shift 4th it will drop into the 30s BUT when i start in 2nd and hard shift into 3rd my trims in 3rd look great and are usually low 40s? It seems that it is fairly consistent with doing it when the throttle chopping occurs and it typically only happens in whatever gear i first start the pull in.

Posting a log would help

It sounds like maybe you are on an absolute map? I find the additive ones are more consistent on trims.

 

[ColonelAdama]

Ok I can see the throttle changes on the map with the changes:

https://datazap.me/u/dven11/log-1724449280?log=0&data=1-4-5-6-8-9-11-14-18-20-25-26-27-28-29

https://datazap.me/u/dven11/log-1724449293?log=0&data=1-4-5-6-8-9-11-14-18-20-25-26-27-28-29

Let me know what you think @ColonelAdama

Follow-up for @Dven11 's car - we did a few more iterations in PMs, here's where we ended up (final pull specifically):

https://datazap.me/u/coloneladama/l...ata=1-2-4-8-11-20-25-26-27-28-29&zoom=304-334

Definitely a bumpy road/traction issues but pulling super strong on this 91/E30 mix! You can see the V24 firmware WGDC updates working nicely on this catless car.

 

[Dven11]

Follow-up for @Dven11 's car - we did a few more iterations in PMs, here's where we ended up (final pull specifically):

https://datazap.me/u/coloneladama/l...ata=1-2-4-8-11-20-25-26-27-28-29&zoom=304-334

Definitely a bumpy road/traction issues but pulling super strong on this 91/E30 mix! You can see the V24 firmware WGDC updates working nicely on this catless car.

Car definitely feels good! I appreciate the help!

 

[i3igpete]

can anyone explain why my trims are at 49 if i roll into 3rd gear but as soon as i hard shift 4th it will drop into the 30s BUT when i start in 2nd and hard shift into 3rd my trims in 3rd look great and are usually low 40s? It seems that it is fairly consistent with doing it when the throttle chopping occurs and it typically only happens in whatever gear i first start the pull in.

Take a note at the RPM range where the high trims are occurring in the first pull. Does your second log have 3rd gear in that same RPM range?

 

[Cfdproductions]

Take a note at the RPM range where the high trims are occurring in the first pull. Does your second log have 3rd gear in that same RPM range?

here is one that I did
with a hard shift from 2-3

here is one rolling into it in 3rd

and here is a 60-130 pull starting in 2nd

 

[Cfdproductions]

Posting a log would help

It sounds like maybe you are on an absolute map? I find the additive ones are more consistent on trims.

Posted some screen shots and it’s on map 6

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