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Terry @ BMS Terry @ BMS is offline
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Join Date: Jan 2008
Default E Series N54 JB4 - 11-18-2010, 11:45 PM

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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.

Last updated: 10/21/15

Hey guys,

This is the central point of contact for all N54 JB4 related information. Anything from install directions, to firmware updates, to settings, to frequently asked questions. Any and all relevant info is linked in this post. If you come across something missing from here be sure to let us know.

Order the full N54 JB4 system here.

JB4 Board Upgrades, 2STEP/NLS, DATA cables, anti-lag, and other add-ons are available are here.

The latest JB4 ISO firmware is posted here.

The same BMS DATA to USB cable is used for all of our tunes and strongly suggested for free software updates and new features as we post them.

JB4 Interface: Latest Interface Download. When updating your interface you may need to first go to "add remove programs" and "remove" your previous JB4 interface.

For the full JB4 Install Guide click here.

If you need directions on how to connect a laptop to your JB4 to update firmware or how to datalog Click here.


Map 0: Stock bypass.
Map 1: 13psi. Suggested for most racing applications.
Map 2: 14.5psi. Suggested for those with exhaust and 93 RM2 or higher octane.
Map 3: Progressive meth mapping with flow sensor failsafe. See guide to enable. Meth use isn't supported/suggested without a flow sensor and map 3.
Map 4: Stock map w/ CAN active. Allows full logging and in dash gauges on the stock mapping.
Map 5: Autotuning map. Boost ranges between 12-17psi based on your cars octane, conditions, and modifications. Fully E85 compatible. If using E85 we suggest around 30% to start. Refer to the E85 FAQ for addl info. Resets to 93 octane level adaptions when selected and adjusts itself up or down from there.
Map 6: User defined map generally only used for diagnostics or troubleshooting.
Map 7: Race gas map. 18.5psi peak boost on the G5 ISO. Requires straight 100-104+ RM2 octane unleaded racing fuel. The expensive stuff. We do not suggest using leaded racing fuel. To use this map with E85 requires the BMS E85 back end flash, inline booster fuel pump, and a 40%+ E85 mix, per E85 FAQ.

1) Steering wheel controls menu and video is in the 3rd post down.
2) JB4 has cold/hot oil protection built in. So expect stock like boost until oil temps are > 160 degrees. Same goes for oil temps > 280 degrees.
3) The JB4 has several safety systems built in that will force a switch to map 4 (low boost) if the JB4 notices various conditions. Including boost over target, fuel pressure below target, and air/fuel ratio running lean. If you ever encounter an automatic switch to map 4 review the FAQ below for addl information.

Those on lower grade fuels, running strong E85 mixtures, larger than factory turbos, or those interested in doing custom mapping will want to load our free JB4 back end flash.


I made a post asking for help in this thread and I can't find it now. Where did it go?

Support requests and bug reports are generally deleted or moved from this thread without being read. If you require assistance from BMS email us at Otherwise for log and tuning support post logs, details, and fault codes in n54tech's support section.

Can I use E85 ethanol fuel with the JB4? If so what mixture should I use?

1) Generally speaking you can run 30-40% E85 without the need for logging or worrying about fuel trims, fuel pressure, etc. Just mix E85 in and select map 5. Done.
2) For those wanting to run higher mixtures (and more power) then you need to datalog. You'll want to first look at your low fuel pressure in the JB4 logs. If that is dropping below 50 then you're maxing out the low fuel pressure and should either reduce the E85 mixture or add a Fuel-IT Stage1 fuel pump upgrade.
3) Next up look at fuel trims. If they are exceeding 50 in the JB4 logs & open loop is already at or above 90, or if you get 29F2 codes from having too high of an open loop, then you need to add the free BMS back end flash for E85 fuels to extend the fueling range. The E85 flash also features VANOS changes, higher than factory timing advance, and some other stuff designed to help make more power on E85.
4) Finally after the flash and low pressure pump, you need to keep an eye on the high pressure pump. If it drops below 9 @ wide open throttle then you're maxing out the high pressure pump and need to lower the E85 mixture or lower the boost in the areas where it's dropping below 10. Alternatively you can add in a port injection kit, meth kit, or TBI injection kit, to augment the high pressure fuel pump.
5) Most cars will need an inline fuel pump upgrade OR meth to run more than 50% E85. We suggest this inexpensive inline option.
6) Using map 7 requires 50-60% E85, the back end flash, AND the fuel pump upgrade.

What is a JB4 back end flash map?

A JB4 back end flash map is loaded on to your DME using a Bavarian Technic cable and free BimmerBoost software. This allows enhanced ignition/knock mapping, fuel mapping, and VANOS mapping, beyond what is possible with the JB4 alone. In addition the flash map disables the speed limiter eliminating the need for extra wires. It's strongly suggested for those using heavy E85 mixtures and also can greatly benefit those on low octane fuels such as 91 octane. JB4 flash map information and software is posted here.

How long does it take for map 5 to adapt?

Map 5 is designed to be continually adapting particularly focusing on the last three minutes or so of wide open throttle activity. Upon selecting map 5 it will default to "93 octane" levels (approx 14psi peak) and adapt up or down from there. Those running E30 mixtures will see the tuning become more aggressive (higher boost, higher timing, leaner AFR) during subsequent wide open throttle pulls while those running lower octane mixtures such as 91 octane will see the tuning become less aggressive (less boost, less timing, richer AFR) during subsequent wide open throttle pulls. It's important to note the map learning is always active. So should things take a turn for the worse during a run (intercooler outlet temps rising, oil temps rising, increased engine knock, etc) the tuning will respond accordingly.

What do menu 4/2, 4/3 and 4/4 in dash do and which one should I select?

Menu4 allows you to tell the JB4 whether you are running on the factory flash tuning (4/3 DEFAULT SETTING), a JB4 back end flash map (4/2), or want to run flash only (4/4) with the JB4 providing gauges and/or boost targeting only.

If upgrading from an old JB3 system or JB4 G4 how do I rewire my harness to be compatible with a new JB4 G5 box?

Details are below and it takes around 15 minutes to perform. If after reviewing the guide you would prefer to pay us $25 to do the harness upgrade for you then select the appropriate upgrade kit from our site. We will hold your JB4 upgrade kit until you mail in your harness and box, modify the harness, and send the modified harness and JB4 box back to you. There will be a 1-2 week delay between when we receive your harness and return the modified harness.

For directions on how to modify your old JB3 wiring harness for the JB4 (including the old pin out harness) click here.

Install directions for JB4 G5 SLD wires and how to resolve 29D0 codes if doing a G4->G5 upgrade.

What is menu 5 for? Why doesn't my speed move in increments of 10 when making selections?

Upon installing the JB4 you'll need to use the menu 5 option to properly calibrate your gauges. Otherwise the numbers on the speedo, fuel gauge, and oil gauge won't align properly. You'll count up to 5 then set the tach based on your model and speedo type. Refer to the link below for the steering wheel controls sheet.

How do I read out and delete codes?

There are two methods. The easiest method for beginners is to connect the laptop interface and use the "read codes" button as indicated in the image below. This will give a full listing along with descriptions. Alternatively for more advanced users or if a laptop isn't available you may use the in dash reading on menu 1 option 1. For additional directions click here.

How does the traction assist work?

If you find traction problems too severe in 1st, 2nd, or 3rd gear you can cap the maximum boost/torque achieved in those gears to aid with traction. You'll find them under user settings. A value of 10.0 in 1st and 12.0 in 2nd will limit boost to 10.0psi while in 1st gear and 12.0psi while in 2nd gear. When in 1st or 2nd gear under the boost limit you may hold down the steering wheel volume or talk button to bypass the limit while the button is held down. For example if doing a burn out at the track.

How much boost can I run with a JB4?

The JB4 supports mapping up to 20psi out of the box. This is the limit of the factory TMAP sensor. For higher boost levels, you will need to add in a N20 3.5bar TMAP sensor using a special adapter available on our site. After adding the sensor you will update the "N20 TMAP" field to 1 within the JB4 interface to allow mapping up to 36psi.

Does the JB4 support larger than OEM turbos?

Yes. The JB4 is able to control OEM turbos, hybrid vacuum operated turbos such as RB & Vargas, and single turbo retrofits such as MOTIV, VM, and FFTEC. For hybrid turbos the appropriate back end flash file is required. Once the DME is flashed the JB4 map selection remains the same with the larger turbos. For single turbo kits many additional changes are required. See JB4 single turbo control thread for addl info.

I got a misfire code. What should I do?

Misfire codes are very common on the N54 motor and are generally either a defective plug, coil, injector, or if the misfires happen across multiple cylinders could also be an o2 sensor or high pressure fuel pump. The higher the power levels the more apparent hardware weakness are so often they will crop up first at only higher power levels. Eventually though, they will come up at OEM power levels too. If your plugs have over 15k miles on them I'd suggest switching them out. If that doesn't do the trick you can switch the coil on the misfiring cylinder over to another cylinder to see if the misfire moves with it. If it does, then replace that coil.

My SES light flashed and the JB4 switched to map 4 / low boost. What do I do now?

The JB4 has several active safety systems that will trigger SES light flashes.

The first is the over-boost safety. If boost exceeds the value you've set under user adjustment the SES light will flash once and the JB4 will switch itself to map 4 until you restart the car. The default setting is 18psi. Common causes for this are setting the value too low for the map/intended usage, improperly configured or defective wastegates, or JB4 setting problems.

The second is the run-lean safety system. If your air/fuel ratio (either bank) runs leaner than 14:1 over 4500rpm for more than a second the SES light will flash twice and the JB4 will again switch itself to map 4 until you restart the car. Common causes are maxed out fuel trims (see E85 notes above) or o2 sensor faults. Note any o2 sensor fault must be corrected for the tuning to operate properly.

Another commonly triggered fault is low fuel pressure. If your high fuel pressure drops below 7 (~800psi) the JB4 will flash the SES light three times and switch to map 4 until you restart the car. Common causes are an inadequate low pressure pump, too strong of an E85 mixture for your tuning/fuel pump, or a failing high pressure pump.

What is MaxCool mode?

MaxCool is an JB4 algorithm that improves engine cooling by increasing the speed of the electric water pump and engine cooling fan as a function of water temperature. When enabled you may hear the very loud engine fan and water pump running more often including at idle. MaxCool can be left on full time if you desire and is compatible with add on oil and water coolers such as the BMW PPK kit.

What are the user settings and which ones should I change?

Most are there for diagnostic use only and should not be touched unless you are directed to by your tuner. The settings you might adjust are documented below.

Boost Safety: If boost exceeds this value for more than one second the JB4 will switch to low boost map 4 until the car is restarted. Note this setting has no impact on what actual boost you run. That is determined by the map selected.

1st / 2nd / 3rd gear boost limit: For cars with poor traction limiting boost in 1st gear to for example 9psi and 2nd gear to 12psi can offer your tires some relief.

Default Wastegate Position (DWP): Menu 10 (0-5000rpm). The position the wastegate returns to when making less than 1.5psi of boost. Higher values can make the car feel more responsive but in some vehicles will make it more prone to "wastegate rattle". Lower values of say 800rpm are sometimes preferred to reduce rattle but might make low throttle feel more sluggish. Wastegate rattle is a hardware problem in nature and the software settings can only attempt to mask this issue. In some cases no setting can fully mask the rattle. This setting only effects performance at very low throttle input.

Pedal input: Menu 11 (0-5000rpm). This determines the gas pedal's impact on the boost target. A value of 0 will target 0psi up to 45% gas pedal input while a value of 5000rpm will target 0psi up to 5% gas pedal input. Regardless of setting full boost will be targeted at 100% gas pedal input. Note that depending on your menu 12 setting you will likely make more than 0psi regardless of this setting at lower gas pedal inputs when under load.

Base duty cycle: Menu 12 (0-5000rpm) and represents the minimum duty cycle to the boost solenoids. PWM will not drop below this value regardless of boost. The default setting is 2800rpm which is 28%. Going too high or low on this value may cause over/under boosting during low and partial throttle, surging, boost oscillation, and other headaches. Generally speaking this value should be set between 2400-2800rpm.

Duty Bias: Used for more advanced boost targeting adjustment is described in this thread:

FutureUseD: Various logging parameters which vary by firmware version. Refer to firmware notes valid options.

Does the JB4 support large single turbo retrofits?

Yes! Details & directions are posted here: For those running larger single turbo systems refer to these special notes on how to configure the JB4.

How do I install the 2STEP/NLS add on kit for manual transmissions?

Download NLS/2STEP install guide here.

If I decide to get the optional DATA cable for logs and firmware updates how to I route it?

For the USB cable you have a couple options. Option 1 is to route it over the rubber grommet under the DME cover and leave it there for quick access.You'll just have to lift up the one snap on black panel and can then route it in the window or door jamb. Option 2 is to route it in to the glove box. There is a DIY here:

Do I need to do JB4 logs? If I do logs how do I interpret them?

Datalogging is a more advanced function generally only used when troubleshooting or for those who are looking to extract the most out of their vehicle. This thread contains info on what the various logging parameters mean and how to interpret them.. In addition JB4 logs can be posted in the support section if tuning advice is needed.

Burger Motorsports
Home of the Worlds fastest N20s, N54s, N55s, S55s, N63s, and S63s!

It is the sole responsibility of the purchaser and installer of any BMS part to employ the correct installation techniques required to ensure the proper operation of BMS parts, and BMS disclaims any and all liability for any part failure due to improper installation or use. It is the sole responsibility of the customer to verify that the use of their vehicle and items purchased comply with federal, state and local regulations. BMS claims no legal federal, state or local certification concerning pollution controlled motor vehicles or mandated emissions requirements. BMS products labeled for use only in competition racing vehicles may only be used on competition racing vehicles operated exclusively on a closed course in conjunction with a sanctioned racing event, in accordance with all federal and state laws, and may never be operated on public roads/highways. Please click here for more information on legal requirements related to use of BMS parts.
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