SUPRA ULTIMATE JB4 GUIDE AND LOG REVIEW (V1)

[Hardac_]

Will do.

Though I'm compelled to ask the million dollar question... why is Map 2 so out of whack and inconsistent? Would running Map 1 help to see if its an additive issue with the JB4/my setup?

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[ColonelAdama]

Will do.

Though I'm compelled to ask the million dollar question... why is Map 2 so out of whack and inconsistent? Would running Map 1 help to see if its an additive issue with the JB4/my setup?

Hard to tell, if I had to guess, it's probably because the DP has it a little out of whack. We can swap back to it to try with the FF and Duty bias on Map 4 after trying that.

 

[RyanA90]

@ColonelAdama Awesome thread! Its making me want to convert to JB4 but idk if I have the time and patience to dial in my MT. I know I'll have similar problems as you with the Kenji DP...

 

[swrdply400mrelay]

Hard to tell, if I had to guess, it's probably because the DP has it a little out of whack. We can swap back to it to try with the FF and Duty bias on Map 4 after trying that.

do catted dp's have the same issue?

 

[ColonelAdama]

@ColonelAdama Awesome thread! Its making me want to convert to JB4 but idk if I have the time and patience to dial in my MT. I know I'll have similar problems as you with the Kenji DP...

If you don't already have issues with your JB+, it'd probably be fine!

as soon as I went catless, my JB+ got jerky and I didn't like not being able to log and diagnose.

A JB4 on Map 1 should behave very similarly to the JB+. Am I remembering correctly that's what you run now?

 

[ColonelAdama]

do catted dp's have the same issue?

Usually but much lesser degree than catless.

Exhaust backpressure affects how much turbine energy the DME calculates is needed to spin the compressor to hit a boost target. Less back pressure is simply going to cause overboosting. Catless more severely than anything else.

That's why having the EWG connection is so important. You can mitigate the overboosting by biasing the wastegate open more than the DME tells it to.

 

[RyanA90]

If you don't already have issues with your JB+, it'd probably be fine!

as soon as I went catless, my JB+ got jerky and I didn't like not being able to log and diagnose.

A JB4 on Map 1 should behave very similarly to the JB+. Am I remembering correctly that's what you run now?

Yup I’m on JB+ default position with e30 no problems! Maybe when the weather clears up I’ll think about jb4 a bit more!

 

[totalone]

Usually but much lesser degree than catless.

Exhaust backpressure affects how much turbine energy the DME calculates is needed to spin the compressor to hit a boost target. Less back pressure is simply going to cause overboosting. Catless more severely than anything else.

That's why having the EWG connection is so important. You can mitigate the overboosting by biasing the wastegate open more than the DME tells it to.

Overboosting is when its targeting more than 20psi on map4? so for example ecu requests 20but you get 23 because it can not waste it fast enough from wastegate?

 

[ColonelAdama]

Overboosting is when its targeting more than 20psi on map4? so for example ecu requests 20but you get 23 because it can not waste it fast enough from wastegate?

Yes, but applies to any map. Usually throttle can keep overboosting under control, but it can cause weird DME_BT behavior too.

Just to clarify- overboost is anytime boost > target, which subsequently means ECU_PSI > DME_BT. Usually nothing to worry about between shifts or when you let off.

 

[totalone]

Yes, but applies to any map. Usually throttle can keep overboosting under control, but it can cause weird DME_BT behavior too.

Just to clarify- overboost is anytime boost > target, which subsequently means ECU_PSI > DME_BT. Usually nothing to worry about between shifts or when you let off.

Thank you!
I wanted to share some logs with you once I get my car back. I was also going though my logs on map4 and tweaking a bit, trying to learn it by my self to have some idea.
I am on AA downpipe and MPE with 93 octane

 

[table]

Kinda off topic, but I must ask. Is the JB4 now CARB legal? Or is it just the "BMW B38/B46/B48/B58 JB4 Tuner" not the "JB4 Tuner for 2020-Present Toyota Supra Mk5" despite them being the same egine.

 

[ColonelAdama]

Kinda off topic, but I must ask. Is the JB4 now CARB legal? Or is it just the "BMW B38/B46/B48/B58 JB4 Tuner" not the "JB4 Tuner for 2020-Present Toyota Supra Mk5" despite them being the same egine.

Must be both because they are identical units.

 

[ColonelAdama]

For anyone curious - Here is the MT tuning strategy that worked for me. It is currently running 4-5 psi over ECU_PSI without throttle closure while catless.

This is on 93, so you can clearly see that MT fuel headroom is poor compared to an AT car. (trims)

https://datazap.me/u/coloneladama/log-1707228942?log=0&data=1-2-3-4-8-15-20

• V24 Firmware with WGDC limits unlocked. (requested from BMS)
  • If you aren't catless, probably not needed.
  • On V22, WGDC cannot drop below 29. I need it at ~20 at lower RPMs.
• Map 6 boost targets similar to Map 4, with less mid range boost due to trims
• ~3 psi underboost
  • ECU_PSI always stays ~3 psi under DME_BT
  • FF=35 (varies car-to-car)
  • Duty biases that took months to finalize, preventing weird DME_BT drops (varies car-to-car)
    • Lowered DBs in any RPM range that experienced unusual DME_BT behavior
• PID OFF! PID gain =0
  • FF=WGDC
  • turned off PID gain because boost_error will always be high due to underboosting
• About 20-30 revisions of frustration

Yes, it can be done. I hope figuring out these tricks can save other MT owners a lot of time, but it will be much harder still compared to an AT car, and less powerful.

I can probably eek out another 1 psi across the board for a stout 19 psi map on 93 octane. Doesn't look like E blending will be possible with trims > 40

These DBs would probably be a good starting point for any catless B58.

duty_15	duty_20	duty_25	duty_30	duty_35	duty_40	duty_45	duty_50	duty_55	duty_60	duty_65	duty_70
27​	27​	27​	27​	30​	32​	35​	42​	50​	57​	60​	60​

 

[swrdply400mrelay]

Kinda off topic, but I must ask. Is the JB4 now CARB legal? Or is it just the "BMW B38/B46/B48/B58 JB4 Tuner" not the "JB4 Tuner for 2020-Present Toyota Supra Mk5" despite them being the same egine.

I asked Burger, they said the Supra one is not, nor do they have plans to get it CARB legal. Though the two units are identical, and you can use the BMW one for the Supra.

From what I understand, CARB does not care if it's the same engine in a different brand car, it still has to go through CARB certification which costs companies money. With low volume Supras, I'm not sure it would be worth their time.

If you went to SMOG, not sure if they would look up the CARB EO # and see it's for a BMW...

 

[Phantomx]

Any help you can provide using JB4 with MHD BEF? I have the wifi adapter coming then i’ll get the MHD license and have the ECU unlocked within the next week or so, everything seems to have to come from Cali and i’m in FL so shipping takes forever.

Currently been running JB4 on Map 5 with E30
Current Mods:
Injen CAI with Charge pipes
Dinan CF turbo inlet tube
AFE Full Exhuast
Kanji Garage catless DP

Trims are maxing out currently so want to flash with MHD to help the JB4 from my research this combo is pretty awesome. Also debating just MHD E30 tune no JB4 but since you and Jesse have a of experience would love to hear your thoughts.

If I do JB4 with MHD which map on JB4 should be used and which OTS map (if anyone knows) for the current mods?

Here is the log from the last time I did it with the current mods:
https://datazap.me/u/phantomx2k/fbo?log=0&data=1-4

Any help is always appreciated don’t mind paying for good advice

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