[chenry]

I don't understand (sincerely) - why there is a need to stack a piggyback with a flash - shouldn't the flash be all you need? Can someone explain...thanks!

In other words what is the flash not addressing (or cant) that they piggyback is (or can)

I see this coming up now and again - and almost posted this in one of the flash posts - but figured it best to start a new thread

Thanks again

[canman111]

I've read people when they run methanol they use a jb4 to control methanol and the flash for everything else.

[B58togo]

As stated above, for meth control, but also for the ability to datalog and monitor various parameters when running Bluetooth. Can also control the exhaust flap.

[BMWILUVU]

Originally Posted by chenry

I don't understand (sincerely) - why there is a need to stack a piggyback with a flash - shouldn't the flash be all you need? Can someone explain...thanks!

In other words what is the flash not addressing (or cant) that they piggyback is (or can)

I see this coming up now and again - and almost posted this in one of the flash posts - but figured it best to start a new thread

Thanks again

They have too much money to waste and like jerky rides. The flash is up against the fuel and torque limit by itself and so is the piggyback.

[335i/335d?]

From another thread:

What is a back end flash map?

For those who prefer flash tunes but want to keep the benefits of JB4
functionality and features just add in a back end flash map. The BEF
are templates you can write to your DME using the MHD or ***********
N54 flashing systems that are specifically designed to compliment JB4
tuning. These maps adjust fueling, timing, load targets, VANOS, and
other functions on flash side while allowing the JB4 to retain its
superior absolute boost control, on the fly map changes, in dash
gauges, shift light, auto learning/self tuning, gear dependent boost
control, data logging, WMI integration, PI integration, NLS, and other
features. It's simply the best of both worlds and greatly eliminates
the need for expensive and time consuming "custom tuning" those
running flash only often have to resort to. Note BMS is not affiliated
with *********** or MHD, does not provide flashing tools, and no
flashing support is provided beyond the templates posted. Contact
*********** and/or MHD directly for flashing support and additional
information as needed.

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

While it's possible to tune an N54 without a JB4 doing so comes with
many disadvantages.

1) 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 if a WG line drops off, and the only fuel pressure safety
provided is when fuel pressure drops down so low fuel injection itself
has to be suspended. In addition to these basic safety systems the JB4
offers layered advanced safety systems. For example it monitors fuel
trims bank to bank and reverts to safety if they exceed more than a
15% variance indicating a possible fuel distribution or o2 sensor
issue. Port injection and WMI add extra failure points and the JB4
control provides advanced safety systems for them as well. The port
injection FAQ covers the basics.

2) The JB4 boost control system is programmed as 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 in dash on the fly 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, 2STEP RPM, 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. The JB4 samples boost and analog sensors
250 times per second and CANbus specific data like air, fuel ratio,
fuel trims, and timing advance 10 times per second.

5) Integrated JB4 features such as no lift shift, 2step, 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. For example
with the JB4 NLS and JB4 port injection control when you press the
clutch in for NLS your port injection flow is momentarily suspended to
avoid huge backfires that have been known to blow out o2 sensors and
in extreme cases blow up intake manifolds. When the DME requests a
torque drop due to traction or stability control the JB4, WMI, and PI
systems all respond accordingly. JB4 anti-lag has a dedicated user
adjustable boost limiter to avoid unnecessary engine stress while
engaged. 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
diverters/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) 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.

7) 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 JB4's 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.

I would like to have the fuel cap removed but still be able to change between maps; I use EU 102 octane but in some cases I have to fill it up with EU 95 octane. Further the datalogging of the jb4 is great and I like their service.

[B58togo]

Originally Posted by BMWILUVU

They have too much money to waste and like jerky rides. The flash is up against the fuel and torque limit by itself and so is the piggyback.

Not so. The jerkiness from the JB4 is not there with a flash tune. All the JB4 would be doing is monitoring and logging.

[kern417]

As everyone else said, my understanding is no flash offers the same level of adjustment and features that JB4 offers. Logging, gauges, hardware tweaks, etc. I think of it less as a stack or more as a flash tune + 2nd "coding" tool that unlocks other features for the car.

[E90ROXS]

Originally Posted by kern417

As everyone else said, my understanding is no flash offers the same level of adjustment and features that JB4 offers. Logging, gauges, hardware tweaks, etc. I think of it less as a stack or more as a flash tune + 2nd "coding" tool that unlocks other features for the car.

Only when you know what you are doing with the JB4.

[rjd_F30]

Originally Posted by kern417

As everyone else said, my understanding is no flash offers the same level of adjustment and features that JB4 offers. Logging, gauges, hardware tweaks, etc. I think of it less as a stack or more as a flash tune + 2nd "coding" tool that unlocks other features for the car.

bootmod3 offers all of those things Though I'm not sure what you mean by hardware tweaks.

But there is still reason to stack a flash and a piggyback, and as others have mentioned, that's for meth or ethanol control in some cases.

[kern417]

Originally Posted by rjdnyy224

bootmod3 offers all of those things Though I'm not sure what you mean by hardware tweaks.

But there is still reason to stack a flash and a piggyback, and as others have mentioned, that's for meth or ethanol control in some cases.

I'm used to tuning platforms that offer a lot of other options so I'm surprised how the BMW aftermarket works. But glad to hear at least one company offers a full package. I know in another thread where I mentioned I was waiting for a tune instead of running a JB4, Terry listed out a bunch of reasons why JB4 is still valuable and that was one of them. And then by hardware tweaks I mean getting your boost gauge to show in the instrument cluster, controlling exhaust flaps, etc.

[rjd_F30]

Originally Posted by kern417

I'm used to tuning platforms that offer a lot of other options so I'm surprised how the BMW aftermarket works. But glad to hear at least one company offers a full package. I know in another thread where I mentioned I was waiting for a tune instead of running a JB4, Terry listed out a bunch of reasons why JB4 is still valuable and that was one of them. And then by hardware tweaks I mean getting your boost gauge to show in the instrument cluster, controlling exhaust flaps, etc.

For sure. JB4 is definitely a complete package as far as piggybacks go, but BM3 offers all the stuff JB4 does, save for using the gauges as a menu or boost gauge etc. Also should point out that I don't think BM3 is available for the B series yet (that's what I get for venturing into the B58 subforum lol) but everything I mentioned has been true for the N series engines and when it comes out for the B series, those features will be maintained and maybe some new ones will be added.

[B58]

All you need is a combination of a JB4 + future BEF and the car will be good to go. The current flash tunes on the market for the B58 are not so impressive to me.