SUPRA ULTIMATE JB4 GUIDE AND LOG REVIEW (V1)

[ColonelAdama]

SUPRA ULTIMATE JB4 GUIDE AND LOG REVIEW (V1)

Been a busy 5 months learning nearly everything there is to know about JB4 on the B58 platform. Funny how trying to get my catless MT running right turned into countless log reviews and custom tuning on the JB4tech.com forum. As Jesse said it best, it's all about experience.

Without further adieu, here is everything I know about tuning with this piggyback:

SECTION 1: Getting Started

• Install guide:
  https://www.jb4tuned.com/instructions/JB4_BMW_B48_B58_INSTALL_CARB.pdf
• A used unit may not have an EWG connection. I highly recommend having this. Especially if you have an aftermarket downpipe, or want to run ethanol, or want to use absolute boost control. Just get the dang thing if its missing.
• If you have a new unit, congrats. You already have one. Install is easy when you remember the stock intake comes out in one piece. And remember to have a pick tool for the connectors to lift them off gently.
• Strongly consider getting the bluetooth connection if you intend to do any custom mapping. The app is something like $30, but it is worth it. Highly recommended for easy logging.
• If you have purchased a used unit, the first thing you will want to do is go back to default settings. There is no reset button. You will need to go to the JB4 forum (https://www.jb4tech.com/forum/model.../4984-jb4-b48-b58-firmware-settings-and-notes) to see the default settings and set them manually.
• Check that the JB4 Firmware version shown in your app is the latest stable version. If not, updating takes 5 min. Keep the car on, engine off, phone battery charged (enough). Maybe turn off other bluetooth devices if you have a lot connected.

SECTION 2: Selecting a map

• JB4 works by modifying the MAP and TMAP sensor readings to tell the car’s DME that more (or less) boost is needed. The EWG works the same, but for wastegate position.
• The JB4 has two modes of boost control, which is how it achieves power gains.
  • Additive - the boost targets are an offset on top of stock boost requests.
  • Absolute - the boost targets are fixed and override stock boost requests.
• When you connect with the app, you will see the JB4 has 8 maps:
  • Map0: Stock tuning, fully disable JB4
  • Map1: Additive map with peak of 3psi over stock added (91-93 octane)
  • Map2: Additive map with peak of 4psi over stock added (~93 octane)
  • Map3: Additive map with peak of 6psi over stock added (not recommended for Supra)
  • Map4: Absolute target map with peak of 20psi target (93+ and/or E30 octane) suggested for higher boost models like G chassis, Supra, and Z4. EWG required for proper control.
  • Map5: Absolute target map with peak of 22psi target (E30+ fuel) suggested for higher boost models like G chassis, Supra, and Z4. EWG required for proper control.
  • Map6: Custom tuning map allowing both additive (below 10psi) and absolute (above 10psi) targeting. Setting RPM1500 boost below 5.7psi will make entire map6 additive, setting above 5.7psi will make entire map6 absolute target.
  • Map7: WMI map (boost varies based on WMI additive, meth flow, and other criteria)
  • Map8: VALET / Low Boost Map
• The JB4 ships with Map1 enabled. Remember to set it back to Map1 if you bought a used unit.
• Map1 is the mildest map the JB4 comes with. BMS recommends all JB4 noobs to start by taking a Map1 data log. All fuel is different, your 93 might suck and Map2 won’t work well.
  
  
• In safe conditions, shift to 3rd gear, go full throttle from 2500 RPM to redline while your app is connected to the JB4. It will automatically log the run, and store it under the logs tab. You can then email it to yourself, or just save as a draft (as i do).
• I prefer to turn log grouping off. Depends on who is reviewing your logs.
• The datalog file name will read as your JB4 engine code(P58), the map you were in, how many runs, and the date.
  
  
• Sign up for datazap.me . This website appears to have been made for reading JB4 log csv files (amongst other tuning platforms). They host the logs so we can just link them here. I don’t think csv can be uploaded. JB4 PC app can be used too - see Section 3.
• Here’s where you can make a decision: Do you actually want to DIY tune or just have someone more experienced do it?
  • non-DIY:
    • Post your log (datazap link) in this thread or JB4tech. Myself or others will review as we can.
  • DIY:
    • Keep reading
• Provided that your Map1 ignition advance and fueling look good- Map 2, Map 4 can be logged on 93 octane or higher. I do not recommend Map 3 for high boost B58 models like the Supra. Its more intended for Gen1 or non TU engines.
• Access to ethanol will open up options for those on 91 octane to use maps higher than Map 1, and those with 93 octane to try Map 5 or improve their existing maps. I will write more later about E-blending.
• Remember, always log at lower settings/Maps before moving up. If you aren’t sure if the log is any good, post it for review.
• Set a boost safety (boost failsafe) of ~2-3psi above your maximum boost. For most people, 23 is a good set point. If you are running high boost, something like 25-26 works. this failsafe protects your turbo and engine in-case you goof something up with wastegate tuning, for example.

SECTION 3: Datalogging

• So you’ve got a datalog, or a hundred (if you don’t group logs) lol
• You can either use the official JB4 app or datazap to read the csv. Or excel, google sheets, or JMP if you’re weird like that (yes I’ve seen it lol)
• I, personally, am not familiar with the JB4 PC application, but the instructions can be found here: https://www.jb4tech.com/forum/model...eview-ab/138-jb4-laptop-connection-directions
• I like using datazap because it lets me configure multiple views easily. This means I can look at different groupings of engine parameters during the run to make it easier to interpret. I will get into which groups I use after talking about the parameters:
  
  
• Parameters:
  • Boost: This is the pressure, in PSI, in the charge pipe just before the throttle valve. Under ideal conditions the boost value will be within 1psi of the boost set point value (see Target). Though this may not necessarily apply to all models (MTs). More on that later.
    
    
  • Target: The JB4's target boost. The value is determined by the JB4s internal mapping and many other parameters including engine speed, pedal input, intake temperature, gear, map-specific boost targets, and other internal logic.
    
    
  • Boost2: Post throttle manifold pressure. This is the boost in psi that your cylinders will receive. The DME will use the throttle to keep manifold pressure under target if the charge pipe pressure (boost) goes above target.
    
    
  • ECU_PSI: The ECU (Engine Control Unit) is just another name for the DME (Digital Motor Electronics) or engine computer. The ECU_PSI is the DME observed boost which is being transmitted by the JB4. When boost is close to target then ECU_PSI will be close to DME_BT (see DME_BT). The JB4 will alter this value above and below DME_BT as needed to manipulate the throttle blade.
    
    
  • DME_BT: The DME_BT displays the current DME boost set point. This is determined by the DME and flash map and will typically stay between 10-16psi on a stock 2021+ Supra. But can vary even more, due to DME logic. This value generally does not effect the JB4's boost target unless it drops suddenly to indicate a fuel ceiling(see Trims), traction control, overboost, etc.
    
    
  • IAT: Intake Air Temperature is measured in the charge pipe just before the throttle valve and can be thought of as intake manifold temperature. It is measured by the TMAP sensor (Temperature Manifold Air Pressure) combination sensor. Both boost and temperature in one physical sensor. High IAT will cause the DME to pull timing, robbing power from the car. This is known as heat soak.
    
    
  • Pedal: Gas pedal input. This is the position of the pedal under your right foot with a range of 0-100%. While using cruise control this value will always report zero. Must be at 100 for the entirety of the run for proper log evaluation.
    
    
  • Throttle: Throttle blade position (0-100%). At full load, the DME will modulate the throttle to keep manifold pressure(see Boost2) under target when Boost exceeds (or almost exceeds) Target. If throttle dips below ~80 mid pull, that indicates some overboosting, and its likely that wastegate tuning is needed.
    
    
  • WGDC: Wastegate duty cycle is most easily explained as “wastegate position offset”. It is essentially the JB4 applying a bias on the wastegate position solenoid to open or close the wastegate as needed to control boost. This is inactive if you don’t have the EWG connection. This parameter is formulated something like this:
    • PID Output = boost_error (boost vs. boost target) * Internal Mapping * PID Gain (see wastegate tuning)
    • WGDC = FF + PID Output
  • FF: Short for "feed forward" or the fixed component of the PID boost control system. This is the starting point for boost control and the PID will then adjust WGDC above or below this value as needed for fine tuning. The user adjustment variable FF / wastegate adaptation value (0 -100) scales the FF value and will adjust itself over time as part of the normal JB4 learning routines. In addition, this value can be user adjusted by RPM using the duty bias settings(see wastegate tuning). The default value of FF is 50, but you may see it change across logs. If you don’t want it to adapt, enable Bit 1 under options. Duty bias ("FF by RPM") settings do not adapt.
    
    
  • Ign1-6: Ignition Advance is the number of crank degrees BTDC (Before Top Dead Center) when the spark is turned on to ignite the fuel/air mixture in the cylinder. In JB4 world, we want to see all 6 cylinders climb linearly to redline. Any step down in that climb is a timing correction. A drop greater than 3 degrees usually indicates insufficient octane, but not always. Ign advance is very important. 1 deg of timing is arguably more power than 1 psi of boost (actual tuners correct me). So keep this in mind when you start cranking up boost levels. It’ll also be healthier for your engine to not pull timing.
    
    
  • Trims: Fuel trims (0-50). The Trims display shows what the STFT (Short Term Fuel Trim) signal is doing. This value is displayed as 25 = 0% trims, 50 = +33% trims, and 0 = -33% trims. This is the difference between how much fuel the DME expected(from stock map fuel lookup tables), vs how much it actually needs to keep AFR(see AFR) on target. Since JB4 can’t control fuel, it relies on the DME to make these corrections. So usually trims will be higher than 25. I typically advise people to keep their maps under 40 trims, but if you log frequently, you may be able to push it a little more while keeping an eye on AFR. You can sometimes lower your boost targets in RPM ranges with high trims to mitigate this. The biggest factor for high trims is E content and the delta between ECU_PSI and Boost.
    
    
  • AFR: Air/Fuel ratio. B58 typically targets Lambda=1 (14.7:1) for most situations, but at high RPMs, or poor octane, or high cylinder/exhaust temps, it may start to get into the 13s. You will usually see this in low to mid 14s. No need to be alarmed. B58s run lean due to direct injection. You may see a spike on throttle let-off or gear change (see Autoboost Redux). If it is not sustaining 15+ for more than a couple data points, its not much to worry about. If your trims stay pinned at the top, you have an issue.
    
    
  • Meth: More to come on that - Still learning.
• Recommended Parameter Groupings -
  • Config 1: Boost control
    • RPM
    • ECU_PSI
    • Boost
    • Target
    • WGDC
    • DME_BT
    • FF
    • Throttle for diagnosis
  • Config 2: Fuel and Timing
    • RPM
    • Trims
    • AFR
    • IGN1-6
    • FP_L and FP_H if AFR and Trims are high
• Config 1 allows you to verify the car is near its boost targets and that WGDC is following FF closely. Meaning the PID output and boost error is small. If WGDC is not staying near FF, wastegate tuning is likely needed. Almost always necessary with catless DPs, and some high flow. You will also likely see a lot of throttle activity. More on that later.
• Config 2 allows you to verify the car has enough fuel headroom, and that the octane is sufficient for the boost targets. Read about Trims, AFR, and Ign1-6 above.
• If something seems unusual, I check that Pedal is at 100. Then I check to make sure there wasn't a traction loss event that can cause boost and timing drops. I just look at the RPM curve - if it has any sudden steps, it was probably wheelspin or clutch/trans slip.

SECTION 4: Ethanol Blending

• It is important to remember that ethanol has less energy density than gasoline, therefore your fuel system will be compensating for the higher volume of fuel. However, it is high octane (usually 105) and has excellent cylinder cooling capabilities. This allows the engine to run cleaner and more aggressive ignition timing (big power gains!) Since JB4's extra boost is already pushing the stock fuel map above normal, it is important to keep watch of trims when blending. I have seen many logs where people have overdone it and leaned out (usually a CEL, possibly limp mode, or trigger JB4 AFR safety)
• Per your Supra's owner's manual - up to E25 is permitted on the stock map, so generally that is my max recommendation to begin with.
• You can achieve this by following roughly a 1:3 ratio of E85:gas when you fill up. Typically this is about 3 gallons of E85 into an empty tank, and the rest with gas.
• I tend to start with just 2 gallons, as usually that is enough to start cleaning up ignition timing, without risking hitting the fuel ceiling. Higher E mixes may actually reduce boost targets, as B58 has an internal fuel flow limit.
• After filling, drive a bit(10-15 min) to let it mix.
• Log and watch trims. Generally want to stay under ~45. If you are seeing trims 40+ with your blend, I advise logging more often to check on it and AFR.
• An ethanol analyzer like Fuel It can help if you want to run higher blends of E and higher boost. It can integrate with JB4, and will show ethanol content in your gauges and logs. It cannot "auto-tune/flex-tune" your maps, however.
• If your tune is turned to 11/10 (ie 22+ psi) and requires high octane and minimum E content, an E analyzer is strongly recommended.
• If you are running moderate boost map like 2 or 4, you may still benefit from a little ethanol even if you are on 93 octane. All depends on timing corrections. E analyzer probably not needed since they won't be as octane sensitive.

SECTION 5: Wastegate tuning (FF / Duty Bias)

• Usually needed for any car with non-OEM downpipe to compensate for the freer flow.
  • Used to prevent overboosting at low-end and midrange.
  • Used to reduce throttle intervention for boost control.
• Here is a valuable resource that I learned from that can help until I write this section:
  https://www.jb4tech.com/forum/model...g-review-ab/4229-jb4-duty-bias-ff-tuning-info
• N54, but still 90% applicable.
• FF value is saved PER MAP, but duty bias is global.
• You can seriously screw up your tune here if you don't fully understand it - be warned.
• High flow catted DPs or Catless DPs WILL need duty bias adjustments. Here is a good starting point:

  • duty_15	duty_20	duty_25	duty_30	duty_35	duty_40	duty_45	duty_50	duty_55	duty_60	duty_65	duty_70
    32	32	32	32	35	36	39	48	55	57	62	62

    Not every car is the same. Probably will require more fine tuning, but these have worked for several cars without many adjustments needed.

I will likely write more about options settings, Map 6 configurations, and some general diagnosis of common issues I have seen - including tuning MT Supras. I may elaborate a little more on the techniques I use to begin custom tuning a car at a later point.

Hope this helps you get started with JB4.

Since others have asked: Tips/donations not required but very much appreciated for guide support and log reviews! Venmo - @ColonelAdama

Sponsored

 

[ColonelAdama]

Post saved in case there is a character limit

 

[Josh George]

Thank you for writing this!

 

[Hardac_]

You are the fucking man, this is what a car community is about. Not gating this behind $500. Glad to see you here from over on N54. Installing my JB4 today after work.

Do you have a Cash App or something for donations?

 

[ColonelAdama]

You are the fucking man, this is what a car community is about. Not gating this behind $500. Glad to see you here from over on N54. Installing my JB4 today after work.

Do you have a Cash App or something for donations?

Glad you found the guide helpful! Any tips are appreciated for sure! Venmo is same as my username here - @ColonelAdama

Good luck getting your JB4 setup, any questions you may have can be posted here.

 

[ColonelAdama]

Just wrote a section on Ethanol blending, as it is common for people to run too much and go lean. I have seen many logs like this.

It is best to start low (~2 gal), as each car can vary how it handles the extra fuel load.

 

[Hardac_]

Map 2 log here. I didn't read ahead of time and skipped Map 1, hope it's okay.

https://datazap.me/u/adm613/1st-day-1st-pull?log=0&data=1-4

I don't quite know what I'm looking for yet, but the car felt great. I was foolishly running Circle K 93 octane at the time, but have since filled up at Shell's 93.

The car has a cold-air intake, downpipe, and cat-back exhaust as its major upgrades.

 

[totalone]

Similar mods. Following

 

[Erty]

• Per your Supra's owner's manual - up to E25 is permitted on the stock map, so generally that is my max recommendation to begin with.

Why is this my first time hearing about this lol following this thread thanks again!

 

[swrdply400mrelay]

Thanks for the info!

What mods have you done to your MT Supra?

What are the limitations of the JB4 vs unlocked ECU with BM3/MHD?

Thinking about getting an AA catted dp + DAW hypercore - would JB4 suffice?

 

[ColonelAdama]

Map 2 log here. I didn't read ahead of time and skipped Map 1, hope it's okay.

https://datazap.me/u/adm613/1st-day-1st-pull?log=0&data=1-4

I don't quite know what I'm looking for yet, but the car felt great. I was foolishly running Circle K 93 octane at the time, but have since filled up at Shell's 93.

The car has a cold-air intake, downpipe, and cat-back exhaust as its major upgrades.

Looks pretty good. Octane seems fine. I do see some boost spikes that kind of look like they may be caused by wheelspin but not completely sure. It is potentially overboosting from the downpipe (see throttle activity). I think it may be worth doing some logs on Map 4 as well! Much easier to control boost on absolute maps.

Catless or catted? Duty bias will likely need to be modified.

 

[ColonelAdama]

Thanks for the info!

What mods have you done to your MT Supra?

What are the limitations of the JB4 vs unlocked ECU with BM3/MHD?

Thinking about getting an AA catted dp + DAW hypercore - would JB4 suffice?

My MT Supra just has a Function Werk catless DP and JB4.

JB4 biggest limitation is inability to control fueling. So it can only push up to 33% more fuel than the stock map calls for. This makes it harder to make big power with ethanol. Also makes it harder to run high boost below 4k rpm or so. An unlock with BM3/MHD would likely be much torquier, but I don't think the peak power would be that far off.

JB4 can't control timing either, so it just runs stock timing maps. Again, its fine, but prevents it from being as powerful as say, an E30 OTS map from BM3 or MHD.

It is easiest to view JB4 as an advanced boost controller rather than a conventional tune.

Edit: @swrdply400mrelay - Jesse says JB4 works with hypercore, so I'll take his word for it. I have never tuned any non-stock turbo car though, but would be willing to learn.

 

[Hardac_]

Looks pretty good. Octane seems fine. I do see some boost spikes that kind of look like they may be caused by wheelspin but not completely sure. It is potentially overboosting from the downpipe. I think it may be worth doing some logs on Map 4 as well! Much easier to control boost on absolute maps.

Catless or catted? Duty bias will likely need to be modified.

Catted AA downpipe. Traction control was on, but it did kick in a lot and was in a sandy/dusty industrial area. I think I saw the same boost peak of 27.2 and another later, it seemed it was whenever I suddenly dropped the throttle to 0 from WOT, but I'm probably misreading that.

I'll find some clean roads and do some more Map 2 and Map 4 runs.

Thank you!

Btw, greetings from Columbia my fellow SC-ian.

 

[ColonelAdama]

Catted AA downpipe. Traction control was on, but it did kick in a lot and was in a sandy/dusty industrial area. I think I saw the same boost peak of 27.2 and another later, it seemed it was whenever I suddenly dropped the throttle to 0 from WOT, but I'm probably misreading that.

I'll find some clean roads and do some more Map 2 and Map 4 runs.

Thank you!

Btw, greetings from Columbia my fellow SC-ian.

Sweet, AA is not that hard to dial in with wastegate tuning.

We will do that after seeing the Map 4 log though.

Boost spikes when you let off the pedal are pretty normal. Throttle plate closes and that high pressure won't enter the cylinders. (see boost2)

Ha, this fellow SC-ian would be happy to show ya all the great roads up here if you're ever in town

 

[Hardac_]

Sweet, AA is not that hard to dial in with wastegate tuning.

We will do that after seeing the Map 4 log though.

Boost spikes when you let off the pedal are pretty normal. Throttle plate closes and that high pressure won't enter the cylinders. (see boost2)

Ha, this fellow SC-ian would be happy to show ya all the great roads up here if you're ever in town

That is an offer I would love to take you up on in in the not too distant future. In a similar vein, Kershaw is just down the street from me and CMP is a fantastic and beginner friendly track. Our Supras do wonderfully around there. I'm waiting to go back once I iron out this JB4 and finally get my MSS springs installed.

More logs pending...

Sponsored