[Brandon818]

I know I'm probably going to start a pissing match rn. However I'm curious about peoples opinions. I currently have a jb4 and am satisfied, however I not fond of piggy's and am thinking about switching to MHD and Bq tuning. I have a 335is and know the jb4 dosent work well with it. The few things that a delaying my switch is dyno numbers and actual power. I'm worried I wont be at the same power level I am. Anyone that have numbers to prove that one tune gives more ponnies on stock turbo's.

edit: my car also feel's like its hesitating and barely hit's 16 psi on 30-40 % e85 to 91, car sometimes hesitates on map 1 and 5 w/o E85

[RSL]

Let me pee in the pool first and get out then lol

JB4 is not a "tune". The sooner you realize that, the quicker you'll make a move. The tune you have now is stock unless you're running a backend flash with the JB4, but you're better off flash only, particularly on DCT, as you seem to know. Theoretical limit for power is your environment, hardware and octane, nothing will change that. If you're using JB4 without a BEF, you're running higher boost at lower reported loads that aren't tuned for it and probably making less power because of it (different AFRs, VANOS, higher timing targets with probably corrections like crazy on 91, etc.). Post some logs.

You'll need JB4+BEF to maximize power on the JB4, which means you'll need a flash. At that point, JB4 is literally nothing more than a simplified and glorified boost controller and doing nothing flash only can't, except the JB4 is still hijacking signals and reporting BS values to the DME and there's no need for it.

I used JB4 for about 4 months when I first got my IS an eternity ago, then tossed the JB4 in a box where it sat for years, went to Cobb, then MHD, then tossed JB4 back in with MHD for about another 3 months just to see, then back to just MHD and JB4 went in the trash to make sure I never talk myself into giving it a 3rd chance. Just cut to the chase and go custom flash only.

[Mike@N54Tuning.com]

With a 335is DCT you'd definitely want to load up a back end flash map which you can do for free using *********** or for $79 using MHD.

From the JB4 BEF FAQ:

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.

[Boland01]

We have a JB4 on one car and MHD on the other two. The JB4 does have some on the fly features MHD does not. Both systems do what they are intended to. However, for the price and what it does I would now lean towards the MHD at least on the E90 platform.

[McLovin335i]

I love how my 335 runs with MHD and the E40 map. I drove on some twisty highways this last weekend and the car just flew! I almost compare the power to old motorcycles I used to have. You have no problem passing slow cars for sure. Still trying to save up for the walnut blast and vacuum hoses to help even more.

[nissubaru]

Originally Posted by RSL

Let me pee in the pool first and get out then lol

JB4 is not a "tune". The sooner you realize that, the quicker you'll make a move. The tune you have now is stock unless you're running a backend flash with the JB4, but you're better off flash only, particularly on DCT, as you seem to know. Theoretical limit for power is your environment, hardware and octane, nothing will change that. If you're using JB4 without a BEF, you're running higher boost at lower reported loads that aren't tuned for it and probably making less power because of it (different AFRs, VANOS, higher timing targets with probably corrections like crazy on 91, etc.). Post some logs.

You'll need JB4+BEF to maximize power on the JB4, which means you'll need a flash. At that point, JB4 is literally nothing more than a simplified and glorified boost controller and doing nothing flash only can't, except the JB4 is still hijacking signals and reporting BS values to the DME and there's no need for it.

I used JB4 for about 4 months when I first got my IS an eternity ago, then tossed the JB4 in a box where it sat for years, went to Cobb, then MHD, then tossed JB4 back in with MHD for about another 3 months just to see, then back to just MHD and JB4 went in the trash to make sure I never talk myself into giving it a 3rd chance. Just cut to the chase and go custom flash only.

What about when you are running catless dps? Is it necessary to be running jb4 for the auto code clearing function? I flashed my car back to stock recently, removed jb4 and put the oem dps back in. I'm considering running a BEF but if I don't need the jb4 I'll keep it uninstalled.

[RSL]

Originally Posted by nissubaru

What about when you are running catless dps? Is it necessary to be running jb4 for the auto code clearing function? I flashed my car back to stock recently, removed jb4 and put the oem dps back in. I'm considering running a BEF but if I don't need the jb4 I'll keep it uninstalled.

Cat efficiency codes are disabled in the MHD OTS tunes, but can be enabled again in flash time options if you have stock/catted DPs. If you have a bin you can access in TunerPro, you can disable whatever codes you like to keep the CEL off. The cat codes may already be toggled off in BEF, not sure, but no, certainly don't need JB4 just for autoclear.

[HawkeyeGeoff]

For what it is worth, JB4+BEF is very smooth....JB4 without a BEF is pretty primitive. I am happy enough with the BEF that I'm just leaving it on that and calling it a day.

[Kevinl]

Jb4 without bef sucks compared to mhd

I would just go with mhd only unless you want the novelty the jb4 has

[1932blownhemi]

Tagged for future reference...

[tmick5jr]

Originally Posted by Kevinl

Jb4 without bef sucks compared to mhd

I would just go with mhd only unless you want the novelty the jb4 has

explain..

[x42bnx]

I haven't had any experience with JB4, however as a new 335i owner - I have done extensive prepurchase research because I was excited to get into this.

In my opinion, it seems that MHD has made it so simple to flash a vehicle. I have changed tunes as I have upgraded multiple times and the simplicity of it is astounding. As far as drive-ability, it's consistent and I know what to expect. That was the major deciding factor, I wanted peace of mind knowing that the ECU was flashed and not being 'tricked' into what you wanted it to do.

[F10onesimus]

Buger tuning Jb4 harness b stage 2 n55 e-series used 375 obo

[Faredo]

Ive had a G5 jb4, Jb4 with BEF and MHD Stand alone.

jb4 was ok but it just didnt have the same finesse. throttle was touchy, boost felt like a miss before it came on hard. Reminded me of an old SAFC piggyback.

I then went BEF and it was definitely better. much better street manners.

I can tell you as far as street and autocross wise I cannot feel the difference between BEF and straight MHD. I've eventually taken Jb4 out and have not looked back. The whole map on the fly thing is over rated to me. I have 2 minutes to change maps if needed, and its not often.