BMS VW GTI JB4 info thread

George Smooth

Drag Race Newbie
South Africa
Use subject to terms and conditions posted at

THIS PART IS LEGAL FOR USE ONLY IN COMPETITION RACING VEHICLES AS DEFINED UNDER CALIFORNIA LAW, AND IS NOT LEGAL FOR USE IN ANY OTHER MOTOR VEHICLE. California law defines a "racing vehicle" as "a competition vehicle not used on public highways." (Calif. Health & Safety Code 39048) This part may only be used on competition racing vehicles operated exclusively on a closed course in conjunction with a sanctioned racing event. Competition-only motor vehicles may not be driven to a racing event on a public highway and must be transported on a trailer or other carrier. USE OF THIS PART IN ANY OTHER VEHICLE MAY SUBJECT YOU TO FINES AND PENALTIES FOR VIOLATION OF FEDERAL AND/OR STATE LAW, WILL VOID YOUR WARRANTY FROM BURGER MOTORSPORTS, INC, AND CAN VOID YOUR VEHICLE'S WARRANTY. It is your responsibility to comply with all applicable federal and state laws relating to use of this part, and Burger Motorsports, Inc hereby disclaims any liability resulting from the failure to use this part in compliance with all applicable federal and state laws.

We would like to introduce users to our latest offering.

The unit is called a JB4 which is the name of our most advanced circuit board with CANbus connection (vehicle data network). It has been tried and tested over many BMW models and it is time for the evolution to start for the VW market.

Upgrade units for JB1 users are available to at this link, both revision 1 and 2 units can be upgraded:

Complete JB4 units can be found at this link:

The JB4 is a true plug and play tune offering safe and adjustable gains.

The unit ships with a base setting in map 1 that increases the boost by +4.0psi over stock that is safe to be used with 91US octane and 95 Euro.

Install instructions:
Install instructions can be found here:

JB1 to JB4 update instructions can be found here:
The JB1 to JB4 upgrade kit can be bought here:

To connect to the unit to make changes or do logs you have two options:
1. Laptop connection using our BMS Data Cable via free Windows and Mac software. (conventional serial cables will not work and possibly damage the board).

2. Via Bluetooth using our JB4 Connect kit that is IOS and Android compatible. The Bluetooth device replaces the need for our BMS Data Cable. On some Android devices users have has success connecting using our Data Cable. The App for the handset has a separate charge and can be found in the Google play store or App store as JB4 Connect.
The App can also be used for a gauge displaying showing true values, has shift light capability and acceleration times are being worked on.

JB4 connect link here:

User interface software:
For users that have opted to purchase the optional but recommended for JB4 BMS Data Cable you will need to download and install the Windows user interface at this link
There is a 3rd Party Developed Mac interface that can also be used, download link can be found here at bottom of post 1

Tutorial of how to install User interface software, connect to unit and make changes.

Video of user interface install and connection:

Directions on installing the interface and connecting to your JB can be found here
Firmware is what runs the JB4 unit. As we release new firmware it will be added to post 3 here.

Base settings

If you need to restore your unit with the settings the JB4 shipped with use the below values.

Map selection:
In order to change the map in the picture below under the logging tab you can pick the required map. Under status the unit must show connected. This is done by clicking file and selecting connect.

Upon shipping the following maps are active:

Maps are based on 60/85//5 and newer firmware.

Map 0: This is a stock map with JB4 logging ability. It is also the starter map for cars that are running flash tunes and are stacking the JB4.
Map 1: Tuned map with a average of 4.0psi over stock. This is the shipped map and is compatible for both 91 and 93 and can be used with cars on hardware.
Map 2: Tuned map with 5.0psi peak boost over stock. 93AKI/98Ron recommended
Map 3 Peak boost 6psi 93AKI/98Ron recommended
Map 4 Peak boost 6psi (Golf R and Audi S3 7speed DSG specific), it has a taper at higher rpm so will also work well for all on 93 in hot climates
Map 5 Absolute map peaking 25 tapers to 20psi. E30 with bolt ons needed. (not to be used on 1.8T or 2.0T Jetta)
Map 6: User adjustable boost map. The map comes preset with a 5.0psi over stock peak and is ready to use on any car running 93 octane. The preset map is also suitable for manual cars with clutch longevity in mind.
The mapping can be done in two manners. If the value at 1500 is kept below 10 it will work as a boost adder map. If the value at 1500 is higher than 10 it will work as a absolute map. This means actual total boost targets will need to be entered.
Map 7: Meth integration map using our FSB Meth controller
Map 8: This is a valet map/safety map where 50% of the boost is cut. It is also the starter map for cars that are running flash tunes and are stacking the JB4. It will give the ability to log the car via the JB4. This is also the safety map, so in any circumstance the JB4 detects a unsafe condition regardless of map it will default to this map. This includes knock detection, lean AFR or the boost safety value being triggered due to lack of boost control.

User Adjustment page:

Below is a outline of settings that can be changed in the User adjustment page:

Map 6 (blue outline): as explained above

AFR Bias (red outline): This value is to be set across the range at 100. It is the parameter which adjust the AFR ratio. Unless otherwise advised by us its should be left alone. For cars using the JB4 over a flash tune this value will start of at 0 across the rpm range and working on logs we will advise the end user on the settings.

Boost safety (green outline): This value is a boost ceiling that user will set. It is recommended the value of this is 2psi over peak tuned map. i.e. if you hitting 24psi set this at 26psi. If for whatever reason the car over boosts it will default straight to map 4 returning the car to the stock tune.

Fuel Open Loop (purple outline): This value is what controls the rail pressure to keep fuel trims in check. It is used to avoid having the ECU compensate fuel for the unseen boost. The unit ships with a 40 value. Upon logging some users with hardware may need to raise this value. The ceiling on most cars is 60. For users that are stacking the JB4 over a flash tune this value will be set to 0 initially and via logs we will see if it needs to be raised to compensate for the small boost add.

Max boost 1st, 2nd or 3rd (pink outline): The value added here is the amount of psi the JB4 will cut in the respective gear. With the 60/85//5 firmware it is also possible to go below stock or for flashed guys stacking below the flash request. If you feel hesitations in the specific gear with large max boost numbers it means the value is too high and must be dialed back.

Autoshift boost redux: This parameter allows the JB4 to cut boost momentarily between gear changes. If you see in your log throttle closures post shift or over boost start with a value of 60 and increase in 10's and see if the issue persists. If not its related to too high a boost at rpm of the gear landing point.

Code and Fault reading: At first release the unit will only be able to read faults in Hex Code and clear them. The next firmware update will bring the translation of the code into the user interface as well as activate the autoclear feature for users with **’s.
For now use E Series N54 in the setting page:


The JB4 now has full logging ability and all the parameters on the logging page are logged. The only three parameters to be added in the next firmware update is the oil temp, water temp and transmission temp.
Ign 1 represent overall timing with Ign 2-5 timing adaption and the rest are self explanatory. IAT is the value in F x10.

More on logging in post 2

The JB4 now has full logging ability and all the parameters on the logging page are logged. The only three parameters to be added in the next firmware update is the oil temp, water temp and transmission temp.
Ign 1 represent overall timing with Ign 2-5 timing adaption and the rest are self explanatory. IAT is the value in F x10.

Below a illustration of what a log will look like with a lot of parameters selected on display.


The JB4 firmware for data cable can be found at this link, go to 60 - VAG Gen3 To upload it connect to your JB4 unit (Key on but engine not idling). Go to File then Upload firmware and select the saved file from your laptop. If the upload fails try again without disconnected.

For phone app via bluetooth make sure you not connected to any other bluetooth device including the media inside the car, smart watches etc. Key on but engine not running. Connect to JB4 with app, Go to settings then firmware update. At the bottom you can browse files. Navigate to 60 - VAG Gen 3 and select the file.


Fault code translations can be found at this link. If a fault is not on the list email a screen shot through to


Can I run the JB4 with another device connected to the CANbus?
No, any other device connected to the OBD port creates latency on the CANbus. The CANbus was designed to allow one device at a time and further data being pulled may create safety issues on the network as well as bad signal to the JB4

Will BMS release cluster display and steering wheel map switching?
At this stage cluster hijack has proven to be cost prohibitive due to the Gateway system used by VW. We are looking at getting cheaper solutions that may be affordable. Steering wheel map switching or in car map switching is something being worked on and will come in a future firmware update.

What future features will the JB4 have?
Currently we working on the code reading ability which will come as the first firmware update. Next in line is an Autotune map. Once we have gathered enough data we will be able to create a dynamic map that will self adjust on the fly maximizing performance regardless of conditions, mods and octane used.
Why is the JB4 released as Beta?
When we release units they stay in Beta for quite a while. Any updates done to the unit are firmware related so they get uploaded using the BMS Data Cable.
The JB1 stayed in Beta for a year with only one update when we opened map 6 use.
The JB4 will be ever evolving as we keep adding features to it relative to customer requests.

Will the JB4 remove my speed limiter?
At this point in time, no. The speed limiter affects many safety parameters and until we are certain there are no ill effects on this we will not have speed limiter removal available. The speed limit exceeded is also a trigger point logged in the ECU which may cause issues down the line for any form of claim.

Can launch control be added for a manual car?
No, at this stage this requires changes in the ECU structure which the JB4 does not access or tamper with. We have had success with this on other brands with add on hardware so its something we to intend down the line.

Can the JB4 support larger turbos?
At this stage on the 1.8T we can support the IS20 and on the GTI the IS38. On the R any larger frame turbo will require a flash of some sort.

How do I know if I can stack the JB4 over my flash tune and what is the process?
This varies on what the flash tune is requesting from the car and if there is room for improvement. If more hardware is used, higher octane or ethanol or meth has been added chances are there is a gain to be had. On stack tuned cars we work one on one with clients so we can understand the trend and get a better idea for the community where gains can be had.

Do I need a professional to custom tune my car if I want more power than the preset maps?
BMS is renowned for its customer service and we can assist any customer with setting his car up to optimize performance. A large online community exists as well where users share their findings. The device works in such a way that it is easy for first time enthusiasts to get a taste of self tuning.

Why does the JB4 read my Vin number and is it Vin locked?
The Vin is read for certain mapping purposes. The unit is not locked to the car which would be unethical and can be resold.

Why is the JB4 cheaper than other options yet more advanced?
The circuit board used in the VW product has been used over many other brands and developed over a period of time so the development cost is spread over many models.

For any questions feel free to post here or email me for a faster response.

How to update firmware:

For firmware updates we suggest you turn off WiFi, change upload timeout to 25, and set your phone next to JB4 box under the hood.

Download firmware using the new JB4 Mobile firmware database or externally by clicking this link.

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George Smooth

Drag Race Newbie
South Africa
Logging and some stacking information.

The JB4 has full logging capability of most of the parameters we need to optimize the tune.

In order to log the steps are simple:

JB4 must be connected to log. A normal USB extender cable will work to get the wire into the car. This must be connected though to our BMS Data Cable. 3rd and 4th gear logs are preferable and if you plan on send them to me at for analysis please do not send 15minutes of driving.

Go to Data Logging next to File at the top, press Start, do the log then press and display. Do your run then press Stop and Display when you are safely stopped. Then go Export and Export log and save the file to your pc. This file can be reopened for viewing by going Data Logging then open log.

It is suggested once you get a baseline log to familiarize yourself with what you can click to see which value. The log is best to be viewed in the JB4 user interface.
Below is a typical JB4 only log that I have chosen that is a good example to explain everything as a lot of interesting things are happening. The car was run over and over 0-150mph prior to this log, its full bolt on with our meth kit.

I will start explaining each line starting from the top.

Pedal: This redline that is pegged against the top show where your pedal position is. In some logging tools available by other tuners they use this as the throttle so people are accustomed to seeing it full.

Throttle position (orange): The ECU uses throttle position to assist with torque targeting. It is the torque targeting that creates final boost hence us seeing boost level going up in summer months. This results in a floating throttle which is normal to a point. We do not want to see this value go down lower than 4000 which represents 40%. Sudden spike straight down are also a problem that that is usually accompanied with the overboost fault.

Meth (dark green line going all over the place): For guys running our FSB meth system this line represents meth flow. It should be pegged at the top of the graph in a straight line if flow is sufficient. This car has a meth flow issue which is also evident in the IAT values further down.

RPM (green line): It is interesting to keep a eye on the rpm signal. Good to see what wheel spin looks like or if you suspect clutch slip it will create curves instead of being straight.

Trims (light blue): For scaling purposes this is a JB4 calculated value using the OEM trim values and taking into account what we doing to the AFR bias. What we want to do in terms of trims is avoid going higher than 40-45%. If the car reaches this point take a note at what your AFR ratio is doing if its taking a dive you are reaching a fueling ceiling. This will only happen if you use too high a amount of E85 on your mix or you are running too high a boost level. At certain point adding boost does not add power so lower the boost in this case. The fuel is sufficient to max the turbo power wise both for a R and a GTI. If the car is run like this for a sustained run the ECU will throw a lean code Sensor 1 Bank 1 and the JB4 will default to map 4. On the ECU reading a value of 25% is no trim. So higher than that means its adding fuel and lower its cutting fuel.
You JB4 should ship with a fuel open loop value of 40. The maximum you can go is 60. Increasing the value will lower trim levels by increasing rail pressure. Dropping the value will increase trims values.

Boost (Blue line): This is actual boost

Target (Pink line): This is the boost target requested in the map 6 column. In this case we targeting actual boost values. If you use Map 6 as a boost additive by adding the values you want over the ECU boost the line will be found at the bottom of the graph as shown on the Stacked log below.

ECU PSI (Black): This is the boost value the ECU is requesting and seeing.

AFR (Mustard): Here we have the AFR value. If you have opted not to run the AFR wire to the lambda make sure your Fuel Bias values next to map 6 chart are all set to 0. The JB4 uses a calculation of the Fuel Bias Values and ECU AFR to work out the true value of AFR. You may see spikes in this value on the gearchange which is a calculation delay bug on the JB4 firmware we sorting out so do not be alarmed with this.

On this specific log it is interesting to note that in this log the AFR in 4th gear ranges from 13.2-12.7 which is a happy place for a Direct injection car. Switching to fifth we see the AFR drop to 11.3. It is rather rare for this to happen but I am glad we got it. The ECU has two mechanisms that are built into AFR functionality. One is a EGT (exhaust gas temperature) protection mechanism that dumps fuel when the EGT's get too high and the other is a full boost timer which is triggered if the car has sustained full throttle runs and it also dumps fuel. I think in this case the second one occurred.

IAT (fine turquoise line)
Overall Timing (thin redline)
IGN1 on logging page
Timing adaption (different colours but timing adaption event circled in orange) IGN 2, 3, 4, 5 represent cylinder 1, 2, 3, 4

The IAT is in Fahrenheit and to get correct value multiply by 10. So if it show a value of 10 its 100F.
On this log the IAT is sitting close to 100F across the rpm range. Ambients where around 100F as well and the meth not working well is not improving it.

What we need to look at in the IAT is a relationship between overall timing and timing adaption. In general the lower the IAT the more timing the car will run. So if you see your timing is lower than usual compare the IAT's of the previous runs to see if its boost or IAT affecting it. As you increase boost you will see the timing chart start dropping as well. In the mid range it is normal for you not to see any timing but at high rpm it has to pick up. This car in the log has got relatively good timing going up to 10 degrees at peak rpm where boost is running at 20psi. If we raise the boost at peak to 22psi we might see a 5 degree drop of timing and we loose any power gains from the boost increase. Regardless in terms of targeting we do not suggest values higher than 18psi at peak rpm. Anything higher in our findings and the timing offset costs far more than the power gained in boost. From 16-18psi at redline we only seeing a average of 4-5whp so its up to the end user to decide how hard he want to push the turbo. We will obviously find good trends from users over time in this regard as well.
On the log I have circled a timing adaption event in 5th gear. There is a lot of discussion about timing adaption on the Simos ECU and it is a general norm to allow up to -4 degrees. On our side we would prefer it to be kept to a minimum of -2 or less or none at all. The timing adaption can work as a function of torque targeting. In this case in orange it pulled -1.2 degrees in cylinder 1. Looking immediately at the previous gear we can see timing was not affected so this is not a issue. For safety purposes we have logged knock sensor values vs timing pull and in most cases there is no relationship.

Gear: The gear will show you which gear you are in. Works for manual and DSG and Auto. It is nice to look back at it because sometimes its hard to remember what occurred when. Also lets us see on our side when logs are sent if we looking at possible wheel spin or a issue.

Stacking the JB4 over a flash tune:

All the above will apply. With the JB4 connected you will start with a clean slate and log the car in map 0 which is a pass though map with logging capability. This will give you a idea of the state of your tune and show you how it is set and what it is doing.

On the user adjustment page you going to want to make the settings as below:

You will notice the boost safety is set to 30psi. Once you know your final peak boost adjust this value to 2psi over the peak so you can still have the safety feature for boost over run.

The same will apply in terms of what you are looking for in the logs. One variance is that the throttle position will stay mostly open due to the torque values in the tune being higher.

Start adding boost in single digits after your peak boost for starters and see how the car is handling it and what the affects are of the added boost in timing.
Keep a eye on the fuel trims and adjust accordingly in denomination of 5 in the fuel open loop setting
You can have a look at AFR values but they rarely move with stock turbos.
Look at the timing pull values vs overall timing. In some cases if timing pull is present you can start adding the fuel bias at those rpm in values of 5. This will en richen the AFR and in some cases the richer fueling can cool the cylinder enough to increase timing.

Be sure to work with me if you going for large increases or you trying to achieve maximum boost values.

Below is typical log. The car is a GTI APR Stage 2+ IS38 running our meth kit.
In this case you will see the pink target line at the bottom which represents boost add. In this case it is set at 1.8psi over stock. Trims have also been brought down the a fuel open loop setting of 20. This actually also improved the AFR curve in the process.

To control the boost per gear in the case of stacking the value you add is the psi it will cut in the specific gear. Boost cut 1st, 2nd and 3rd are used for these. If the value is too high the ECU might trigger a overboost code.

Feel free to ask any questions or email me logs to
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Ready to race!
Hawaii and Utah
George, my unit is enroute, when do you anticipate starting a Map 6 thread?
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Ready to race!
Los Angeles
Nice! This is what I have been waiting for. Can't wait to see what the JB4 is capable of. I'm down to the JB4 and the Cobb AP. Exciting times in the VW community.


Passed Driver's Ed
N.C. Ohio
Hi George,

I have REV1 JB1. Which plug do I not need to use when I upgrade to JB4?

and with the wire tap there are no issues if you have to remove for a dealer visit?



Ready to race!
So I read that we need to tap into the Lambda(O2?) sensor wire. Haven't looked at that part of my car yet, but would it be feasible for me to source the correct mating connectors to make an inline-T harness for the factory connection so I can avoid tapping into a wire?


Go Kart Newbie
No auto clear secondary cat codes yet?

George Smooth

Drag Race Newbie
South Africa
Hi George,

I have REV1 JB1. Which plug do I not need to use when I upgrade to JB4?

and with the wire tap there are no issues if you have to remove for a dealer visit?


LHD Rev1.

On the wire tap can pull the protective cover back on the lambda sensor wire and tap into it. Once the tap is removed it will be no where visible.

George Smooth

Drag Race Newbie
South Africa
So I read that we need to tap into the Lambda(O2?) sensor wire. Haven't looked at that part of my car yet, but would it be feasible for me to source the correct mating connectors to make an inline-T harness for the factory connection so I can avoid tapping into a wire?

The reason we do not have this part plug and play is the lambda sensor side plug only gets shipped to the lambda sensor manufacturer. We ordered to consignments via different sources and both times we got the wrong plugs. Once via the dealer as well. You can give it a shot and see if you get the right one.