SUPRA ULTIMATE B58 JB4 GUIDE AND LOG REVIEW (V1)

[“I’m keeping this stock”]

Honestly I'd just jump to the current V28 T1 firmware (alpha P158) if you had issues on map1. It works better than the "MT mode" workaround. Already sorted mine and another guys MT in like 2 revisions and a single day lol. Basically the MT mode will probably be obsolete since the entire additive boost mode was modified to accommodate our cars.

Post a log though so I can verify

Finally got my new tires on so started messing with the jb4 again. i downloaded p158 v28 and noticed it was on p58 for gen 1 b58. could that have been causing my issues?

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[swrdply400mrelay]

prob not! I'd just stick with the JB+ unless you want to switch to E30.

Yeah, that's too much trouble to run E, lol.

Just wondering how BMS was able to run map 2, didn't gain much hp but +35 torque. Probably not worth the effort?

 

[ColonelAdama]

Yeah, that's too much trouble to run E, lol.

Just wondering how BMS was able to run map 2, didn't gain much hp but +35 torque. Probably not worth the effort?

They probably won't show you the log for that ? not letting anyone here run shitty timing.

 

[razorlab]

Just wondering how BMS was able to run map 2, didn't gain much hp but +35 torque. Probably not worth the effort?

Trust Terry about as far as you can throw him.

 

[Bug2th]

Hope this isn’t too ignorant a question but when I read about timing I just see comments about bad or better timing- what is considered good timing? I know this is dependent on builds and fuel/temp/elevation, etc. but just trying to get a rough idea how it is determined - like for a stock car on 91 is 5 or 10 or 20 btdc considered good? I’ve done a bit of research but couldn’t really find anything. The most info has been a few posts from @Thraxbert.

 

[ColonelAdama]

Hope this isn’t too ignorant a question but when I read about timing I just see comments about bad or better timing- what is considered good timing? I know this is dependent on builds and fuel/temp/elevation, etc. but just trying to get a rough idea how it is determined - like for a stock car on 91 is 5 or 10 or 20 btdc considered good? I’ve done a bit of research but couldn’t really find anything. The most info has been a few posts from @Thraxbert.

The base timing(and boost)will fluctuate based on IATs. What you are looking for is any drop from ign1-6 climbing to redline. No timing corrections = all cylinders converge and climb linearly towards redline

1-2 cylinders dropping <3 degrees is typically OK, just means you're reaching the limit of the octane.

 

[i3igpete]

The convergence of the timing across cylinders matters more the actual magnitude of the datasets. For example, in very hot temperatures, but no knock, the curves will stick together like the top left box. It will just hit a different number at redline - this is fine. The knock algorithms are much more complex nowadays compared to back in the day where there was a simple knock sensor voltage vs RPM calibration table.

 

[ColonelAdama]

The convergence of the timing across cylinders matters more the actual magnitude of the datasets. For example, in very hot temperatures, but no knock, the curves will stick together like the top left box. It will just hit a different number at redline - this is fine. The knock algorithms are much more complex nowadays compared to back in the day where there was a simple knock sensor voltage vs RPM calibration table.

Great example, I'll add to the first post.

 

[Bug2th]

Great example, I'll add to the first post.

Great. Thanks. That gives me a better idea of what to look for.

 

[Cfdproductions]

Couple logs from an auto car that I have been helping out … only doing 60-90 pulls right now, getting the fuel mix dialed in with this new board… took a little while to get the timing figured out

 

[MK5_Pengwn]

@ColonelAdama I newbie to JB4 and I have a 2022 Supra 3.0 Premium. Please take a look at my logs and let me know if more information is needed. Here is a link to my logs on Datazap:


https://datazap.me/u/mk5pengwn/clean-3rd-gear-run-map-1

https://datazap.me/u/mk5pengwn/18-march-2025-runs

Thank you for your time!

Anthony

 

[dAPEX]

2024 MKV Supra 3.0 6 speed manual with VRSF highflow catted d*******, AWE touring catback exhaust, MST cold air intake, JB4 with latest firmware and fuel pressure control running E20 with mix of 93 octane and E85, this log is map 1 in 3rd gear

Map 1 3rd gear:

https://datazap.me/u/dapex/supra-mk...&trim=5&tmin=75.30&tmax=100.00&hg=1-4-18-9-14

Map 1 4th gear:

https://datazap.me/u/dapex/supra-mk...&tmin=75.30&tmax=100.00&hg=1-2-4-18-9-1-10-17
Feels and looks like I'm getting surging/cutting of throttle on 3rd, 4th gear pulls on Map 1 and Map 2.

@ColonelAdama any ideas what is going on with this crazy throttle closure?

 

[razorlab]

Feels like I'm getting surging/cutting of throttle on 3rd, 4th gear pulls on Map 1 and Map 2.

Because you are. Car is not happy. Look at your throttle plate:

 

[dAPEX]

Because you are. Car is not happy. Look at your throttle plate:

Haha, I know I am getting throttle closure based on the log (and how the car is behaving). I don't know how to figure out why. What do you mean look at the throttle plate? Forgive my stupid question. The car has 7k miles and I haven't ever messed with the throttle body. Do you think it is defective? My understanding was that the throttle normally only closes like this when boost is significantly over the target but that doesn't seem to be happening.

 

[razorlab]

Haha, I know I am getting throttle closure based on the log (and how the car is behaving). I don't know how to figure out why. What do you mean look at the throttle plate? Forgive my stupid question. The car has 7k miles and I haven't ever messed with the throttle body. Do you think it is defective? My understanding was that the throttle normally only closes like this when boost is significantly over the target but that doesn't seem to be happening.

Throttle can close based on a bunch of things. Going over boost target, load max, torque max, pressure ratio limitation, traction control, etc.

However, it's usually never a lightning bolt like in your logs. I would say something is wired incorrectly or something else wrong. @ColonelAdama is the resident JB4 master here.

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