JB4 Hesitation

[Mike_f80nyc]

JB4 FTW
Im running JB4 on my car for over 30k miles and never had any issue with the car or with the JB4. Car ran 10.80 at 133mph on stock turbos which is vorld record, now we cannot blame JB4 or any other tune if something goes wrong with the car since we all run high boost. If you gap the plugs to 0.18 they should be good for at least 12,000 miles, since I already experienced that. Good luck OP

[mark5092]

Originally Posted by NJ-M4

Love my JB4.

Have never had any problems with it over the last 1 1/2 years and various mods/setups on my car.

👍🏽

[///F80M3]

Originally Posted by mike@x-ph.com

Op,
Recommend you post longs instead of screenshot and as mentioned above make sure plugs are gaped correctly

Can't attach the csv file so I converted to doc file.

[Mike@N54Tuning.com]

Originally Posted by ///F80M3

Can't attach the csv file so I converted to doc file.

Can't open DOC files in the JB4 interface so that won't work. Most people on here just change the name from .CSV to .TXT or something so the system lets you load them. Or use BMS' support forum which is generally a better source for help.

Mike

[///F80M3]

Originally Posted by Mike@N54Tuning.com

Can't open DOC files in the JB4 interface so that won't work. Most people on here just change the name from .CSV to .TXT or something so the system lets you load them. Or use BMS' support forum which is generally a better source for help.

Mike

Attached the txt files.

[Mike@N54Tuning.com]

Originally Posted by ///F80M3

Attached the txt files.

Runs are short but don't see any obvious issues. Definitely get some new plugs and gap at 0.020". Normally new plugs every 15-20k is suggested, so if you have 38k on yours, might explain the issue.

Mike

[SflBimmer8484]

Plug gap has been a known issue on these cars since they were released and we started upping the boost. If you want to run over 23+ psi gaping is highly suggested. What tune you are running is pretty irrelevant.

[dmk08]

Originally Posted by rmedeir1

+1. JB4 nice but not as smooth and comparable to a VF HEX

I drove a VF stg 2 car and it felt no smoother than my JB4 Map2 E40 mix car. It just felt slower.

[SflBimmer8484]

Originally Posted by dmk08

I drove a VF stg 2 car and it felt no smoother than my JB4 Map2 E40 mix car. It just felt slower.

Unless the jb is running out of fuel I dont see it being that much smoother. The stock dme does a great job with our active -8 controlling all the parameters.

[dmk08]

Originally Posted by Andrew@ActiveAutowerke

Unless the jb is running out of fuel I dont see it being that much smoother. The stock dme does a great job with our active -8 controlling all the parameters.

Yeah 1 of 2 things are happening when JB4 isn't smooth IMO.

-Not enough fuel for the boost you are running.
-DSC is intervening

[SflBimmer8484]

Originally Posted by dmk08

Yeah 1 of 2 things are happening when JB4 isn't smooth IMO.

-Not enough fuel for the boost you are running.
-DSC is intervening

I agree or a spark issue like the Op is experiencing.

[///F80M3]

Originally Posted by Mike@N54Tuning.com

Runs are short but don't see any obvious issues. Definitely get some new plugs and gap at 0.020". Normally new plugs every 15-20k is suggested, so if you have 38k on yours, might explain the issue.

Mike

The dealer just replaced it. I only have 5k miles on the current plugs which is why I thought it was something else.

[Mike@N54Tuning.com]

Originally Posted by ///F80M3

The dealer just replaced it. I only have 5k miles on the current plugs which is why I thought it was something else.

I doubt the dealer gapped them to 0.020" and there is a known problem with OEM plugs having their ceramic break off and drop down. The NGK 97506 plugs are a better choice.

Mike

[mark5092]

OEM plugs come gapped at .028. Dealer installs them that way right out of the box. OEM plugs are very easy to damage if you are not very careful gapping them. The ceramic is easy to damage also. Have to be very careful installing them especially when torquing. You can hear the ceramic crack.

[///F80M3]

Originally Posted by Mike@N54Tuning.com

I doubt the dealer gapped them to 0.020" and there is a known problem with OEM plugs having their ceramic break off and drop down. The NGK 97506 plugs are a better choice.

Mike

NGK 97506 gapped to .020 is better than OEM? I thought OEM plugs were the best option for the S55. Can't wait to see the condition of the stock plugs.

[///F80M3]

Originally Posted by mark5092

OEM plugs come gapped at .028. Dealer installs them that way right out of the box. OEM plugs are very easy to damage if you are not very careful gapping them. The ceramic is easy to damage also. Have to be very careful installing them especially when torquing. You can hear the ceramic crack.

Thanks for the tip.

[NorCal f80]

i was super excited when ecu tunes came out until I read about these nightmare flagging dealer stories. jb 4 for me.

[SflBimmer8484]

Originally Posted by ///F80M3

NGK 97506 gapped to .020 is better than OEM? I thought OEM plugs were the best option for the S55. Can't wait to see the condition of the stock plugs.

We tested every option we could find. In the end we stayed with the gapped stock plugs.

[bmwtrix]

So, I have a JB4 and supposed to get BM3 shortly, do you guys recommend taking the JB4 out completely, or running both? If both, do you keep at MAP2 with the BM3? Or is it pointless? Thanks!

[dmk08]

Originally Posted by bmwtrix

So, I have a JB4 and supposed to get BM3 shortly, do you guys recommend taking the JB4 out completely, or running both? If both, do you keep at MAP2 with the BM3? Or is it pointless? Thanks!

I would take it out unless you plan on using it to stack.

[Mike@N54Tuning.com]

Originally Posted by bmwtrix

So, I have a JB4 and supposed to get BM3 shortly, do you guys recommend taking the JB4 out completely, or running both? If both, do you keep at MAP2 with the BM3? Or is it pointless? Thanks!

To start you'd just leave the JB4 on map4 so you can keep your in dash boost guage & CANflap on BC button active. Then evaluate the mapping with your tuner. Most use map4 for the "flash only" map and then enter a map6 for when they are on higher octane or want a race map. Then you can toggle between your flash only and race map within seconds in dash, keep boost by gear active for the race map where traction might be more of an issue, etc.

Mike

[CaryTheLabelGuy]

Let's dispel some myths in this thread, shall we?

1. The JB4 is not as smooth as a flash tune: The stock tuning tends to overshoot its boost targets often and varies boost targets a lot depending on several conditions (ambient temp/IAT, baro.....etc). With a JB4 (or all piggybacks, for that matter), the situation is exacerbated when the overshoot happens, making it more apparent. What sets the JB4 apart is the fact that it can take direct control over the EWGs which, if you know what you're doing, can smooth out this issue. The issue isn't the JB4's fault, it's the OEM DME tuning. A flash tune can fix this issue, but overshoots and how the DME handles an overshoot can still happen.

2. Drivetrain errors are common with the JB4/ other piggybacks: Drivetrain errors usually happen from misfires that are a result of high fuel trims. When the DME starts to see higher fuel trims (lean), it actually starts to lower target AFRs (Air/Fuel Ratios) as a failsafe measure. The stock fuel system is not "running out of fuel", it's actually the exact opposite. The DME is targeting richer and richer AFRs, which on a DI engine like the S55, will cause misfires if AFRs dip into the 10:1 range, ESPECIALLY if ethanol (or any alcohol fuel) is present. The JB4 can fix this problem if you know how to use the tools the JB4 gives you and you have the Fuel Pressure Sensor hooked up. Again, this sets the JB4 apart from the other piggybacks and is a VERY useful feature, particularly if you want to run an ethanol mix (E30/E40).

3. Traction control: If TC is kicking in, particularly when making significantly more power than stock, it can be quite violent and feel like something is broken or has just broken. I hardly ever use TC for this very reason. If I'm in "beast-mode", TC is OFF. MDM mode isn't much better, either and I only use it in the rain. If you learn how to drive your car with TC off and know how to properly modulate the throttle/counter steer, you shouldn't need TC in most circumstances. HOWEVER, if you aren't familiar with high-powered turbo-charged cars that are rear-wheel drive, you should keep TC ON and just accept the fact that your power delivery won't be nearly as smooth, especially with more power; you will be safer and there is something to be said for that.

4. Spark Plugs: The plug has two main purposes. Ignite the air/fuel mixture and transfer heat from the combustion chamber. It's important to remember spark plugs do not create heat, they only remove heat. The spark plug works as a heat exchanger by pulling unwanted thermal energy away from the combustion chamber, and transferring the heat to the engine's cooling system. The heat range is defined as a plug's ability to dissipate heat. Make sure the plugs are properly torqued as a improper seat will not allow heat to transfer to the head. The temperature of the spark plug's firing end must be kept low enough to prevent pre-ignition, but high enough to prevent fouling. This is called "Thermal Performance", and is determined by the heat range selected. The insulator nose length, gas volume around the insulator nose, the materials/construction of the center electrode and porcelain insulator all determine the plugs heat range. Improper gap can play a huge roll in knock as well. You want to run the most gap possible to better expose the spark to the ignition, but if you run too large of a gap, you will have misfires. If you run too small of a gap, you will increase firing end temp and thus combustion temps/pressures. you must reduce the gap about .004" for every 50 hp you add as a general rule of thumb.

All plugs are notoriously improperly gapped right out of the box, even an OEM plug. Every time you change you plugs, you should confirm the gap and re-gap if needed. The stock plug gap spec is .0314 and will likely need to be gapped-down.

A misfire will register a lean spike if your WB has a high sample rate (the stock S55 WBO2s samples at a high rate and can detect misfires), but it may not be enough for you to see unless it was a serious/consecutive misfire.

A misfire can also be picked up by the knock sensor and registerd as knock, or the most common way to tell if you are missing is a loss in power(shaky torque curve) and a actual "miss" which can be felt and heard along with backfiring..ect.

If your gap is too large, you will most likely get a misfire across all cylinders, in which this case you will deffinatly pick this up using a high sample rate WBo2(fast high spiking lean conditions) and it would be felt and would deffinatly show up on the dynograph.

I also think the S55, making significantly more power than stock, needs at least a step colder plugs. This is something I see constantly overlooked on S55 tuning. I'm just not sure how the stock plugs cross-reference to good aftermarket alternatives from NGK or Denso as I've never actually looked, to be honest. I'm a HUGE fan of NGK's Iridium IX plugs and would need to do a little research on what aftermarket plug would likely work best for the S55.

Each colder heat-range can lower combustion temps by as much as 100*c and typically allow a slightly larger gap.