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Terry @ BMS Terry @ BMS is offline
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Default JB4 MHD Back End Flash Maps for F Chassis //M Models - 08-30-2018, 08:57 AM

With the recent release of F series OBDII flashing tools for MHD its time for a central thread for S55 MHD BEF development discussion.

Wireless Flashing Device:

MHD BEF map templates are provided free of charge.

Click here to download the latest maps. Note they are subject to change and when we make revisions we increment the number on each one to keep track of the changes.

S55 JB4 BEF Map Designations:

RACE: Suggested for most applications including pump fuels and E85 mixtures up to 40%.
E85: Intended for use on E85 mixtures of 40-60%.
E85_IGN: Intended for use on heavy E85 mixtures 60-100% and features more aggressive timing advance for maximum stock turbo performance.
AL or ANTILAG: Added rolling anti-lag logic, requires JB4 wiring change to activate.

Starting work on the FAQ. It's a work in progress. I'll update it as I see more questions come in and as development progresses.

JB4 Map Guide with BEF:

Map0: JB4 fully disabled
Map1: Flash only map with JB4 active for logging/gauges
Map2: 22psi peak absolute target map
Map3: Additive map +5psi tapering to +2psi at redline (same as factory flash)
Map4: Low boost valet map, 11psi absolute target
Map5: //M style map, 13psi down low ramping up to 23psi at high RPM
Map6: Custom tuning map (can be used for absolute or additive based on RPM1500 setting above or below 4psi)
Map7: Race gas map, 28psi peak target
Map8: WMI safety map, profile for stock and larger turbos set based on boost safety above or below 31psi, boost level determined by meth additive and meth flow.

Map Notes:


What benefits does a back end flash map add to the JB4?

Adding in the MHD back end flash map allows adjustment over a wider range of engine parameters than are available with the factory flash. Including direct adjustment of timing and fueling tables, VANOS adjustment, fuel scalar adjustment for heavier E85 mixtures than possible JB4 only, speed limiter delete, optional exhaust burble, higher calculated torque reported to the automatic transmission, and a host of other parameters than are only possible via flashing the DME.

What are the benefits of running a JB4 with a flash rather than flash only for tuning?

While it's possible to tune an M3/M4 without a JB4 doing so comes with many disadvantages.

1) With JB4s unique features and logic paths, combined with the flexibility of adjusting DME tables directly via the back end flash map, you get better quality, safety, and more powerful tuning. The JB4 includes more robust safety systems than are possible via flash only. Starting with fundamental safety systems like reverting to a safety map if boost exceeds your safety setting, if the air/fuel ratio in either bank turns dangerously lean, or if fuel pressure drops below a safe level. While you might think the DME alone can handle these basic safety systems surprisingly it's not the case. The DME will happily let you run along at full power and a 18:1 AFR, with boost pegged, and the only fuel pressure safety provided is when fuel pressure drops down so low fuel injection itself has to be suspended.

2) More mapping options including absolute boost target maps. The JB4 boost control system is programmed to offer both absolute and additive maps. Absolute meaning you'll always target a specific boost level. Unlike the DME which naturally implements a LOAD control system where boost levels go down when it's cold and go up when its warm. The opposite of what you generally want for turbocharged performance. In addition the JB4 is quick and easily adaptable to a wide range of setups eliminating the need for expensive custom boost tuning and the risks that come with repeated logs on systems that are not yet setup. It's not uncommon for engine damage to occur while a new setup is initially being dialed in. The JB4 automatically tunes wastegate dutycycle, fuel trims, and other important tuning criteria full time in the background greatly simplifying the tuning process. In addition the JB4 auto-tuning map can self tune for various ethanol mixtures without the need of an expensive and difficult to install flex fuel sensor. Pedal to boost mapping, spool aggression, boost by gear, and other critical factors can be easily adjusted to suit the needs for the particular track or racing situation.

3) On the fly changes. Whether it's changing the boost/power level, boost by gear setting (including being able to disable it on the fly for burn outs or if traction turns out to be better than expected), pedal input, exhaust flap position, or what gauges are shown in dash, the JB4 allows a wide range of user adjustment real time from the drivers seat without having to use a 3rd party device or risk programming the DME between runs. You're able to make the changes while out on the track where you need to make them.

4) The JB4 allows for much better real time feedback to the driver. User adjustable in dash gauges allow you to keep a constant eye on boost, timing, knock, meth flow, and/or AFR, all selectable and changeable on the fly from the drivers seat. A user adjustable shift light can be triggered making rowing through the gears easier. JB4 Mobile allows wireless bluetooth logging via your Android or Apple phone without a cable locked in your OBDII port. In addition you can select map0 on the fly to allow OBDII port logging and diagnostics when needed for vehicle service. The JB4 default logging set includes all relevant data required for tuning including boost, timing cylinders 1-6, AFR and fuel trims in both banks, high and low fuel pressure, load, calculated torque, trans temperature, and many other parameters. The JB4 provides a simple to use but incredibly robust data logging system eliminating the need to select what parameters to record before each run and providing instant on the fly charting without the need of 3rd party internet programs. We routinely add parameters to the JB4 logging set based on customer feedback and evolving tuning requirements.

5) Integrated JB4 features such as anti-lag, port injection control, flex fuel sensor, and progressive water/meth (WMI) control eliminate the need for independent add on boxes that are more difficult to install and technically unable to communicate with each other. Integration allows these extra features to share information for a smooth and cohesive tuning solution. When the DME requests a torque drop due to traction or stability control the JB4, WMI, and PI systems all respond accordingly. WMI integration is able to hold boost levels low UNTIL fluid is flowing adequately to prevent spool up and transitional knock, adjust your boost target if the fluid being injected turns out not to be as potent as was expected or required to prevent knock, and in the event of a fail-safe depending on the severity of the situation either lower your boost target partially OR instantly dump boost out the diverter/close the throttle/cut timing. These are just some of the many examples of why having add on boxes an features all integrated through a single system is advantageous.

6) Does not require a MAP sensor change for higher boost levels. On S55 models the JB4 can control up to 36psi with both factory sensors. In addition to saving money on a 3.5bar MAP sensor(s) it also reduces headaches having to switch back the hard to reach MAP sensor(s) back to stock when flashing to stock.

7) Free maps for life with no custom tuning required. The JB4 is widely used and widely supported including free unlocked back end flash maps and custom mapping support from BMS via the n54tech support forum. BMS sponsors and attends several 1/4 mile and 1/2 mile races per year continuously improving the JB4 base maps and features based on real world experience and feedback. These updates are provided free of charge to JB4 customers via n54tech firmware posts.

8) The JB4 hardware is robust, reliable, highly developed, and upgradable, with many thousands of systems in use since 2008 when it was first released. The key to the JB4ís success is that it DOES NOT replace the factory engine computer or DME. The JB4 simply adds on to functionality already provided by the DME. As a result the DME remains in full control of your engine at all times with the JB4 dynamically making small but impactful adjustments to add in extra safety systems and features and dramatically improve performance. And unlike disposable flash maps the JB4 is a physical system you can remove and resell down the road.

Once I flash the DME can the dealership tell? What if I flash it back to stock?

Modifying your vehicle is not without risks and we believe flashing the DME is traceable even if flashed to stock. If you are concerned about your warranty it's best not to flash your vehicle. That said when used in conjunction with the JB4's expanded safety systems and mapping use/guidelines, expect a relatively high level of reliability at the elevated power levels.

What flash time options are available?

Certain settings can be toggled on/off or adjusted during the flashing process itself. Including the user adjustable exhaust burble settings, speed limiter delete, cold start delete, CEL delete, etc. MHD will be adding more options as their development progresses.

Burger Motorsports
Home of the JB4 the worlds most popular turbocharged tuning system!

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