JB4 Hesitation

[///F80M3]

I just cleared codes and DME adaptation. Car is running very smooth and almost feels faster on map 0. I'm going to run map 0 for a few days then try map 1/2 again. If i misfire then I'm gapping stock plugs.

[kennkenn]

same here

[JoeyBananas]

Originally Posted by 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.

What plugs do you run with the JB4?

[SflBimmer8484]

Originally Posted by ///F80M3

I just cleaned codes and DME adaptation. Car is running very smooth and almost feels faster on map 0. I'm going to run map 0 for a few days then try map 1/2 again. If i misfire then I'm gapping stock plugs.

What plugs did you try?

[CaryTheLabelGuy]

Originally Posted by JoeyBananas

What plugs do you run with the JB4?

Ive been running the stock plugs. But I'm not running anything crazy and have no plans to.

[JoeyBananas]

Originally Posted by CaryTheLabelGuy

Ive been running the stock plugs. But I'm not running anything crazy and have no plans to.

Ok, so stock plugs on map2 should be fine

[CaryTheLabelGuy]

Originally Posted by JoeyBananas

Ok, so stock plugs on map2 should be fine

Absolutely.

[JoeyBananas]

Originally Posted by CaryTheLabelGuy

Absolutely.

As always, thank you. Always appreciate the info.

[///F80M3]

Originally Posted by Andrew@ActiveAutowerke

What plugs did you try?

Didn't change plugs yet. Going to see if it misfires again

[E92murdered]

Does bt tool work on m4?

[schnell1982]

Originally Posted by 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.

I always enjoy reading your posts

1 thing I have learned recently is the spefic torque for spark plugs on direct injection engines.
Correct torque will set the spark plug to the correct index location.
These are also 1 time use plugs and if they are re-used and re-torqued then the index will be in the wrong location.

In a class recently I attended, it was noted and proven that OEM Mercedes and NGK plugs have a different index
NGK's have been used on a few Mercedes direct injection motors and pistons have melted due to using spark plugs with the wrong index location

[Me333]

I put jb4 at 6000 miles. Nothing was needed. Car drives amazing and beastly.

[mike@x-ph.com]

Originally Posted by Me333

I put jb4 at 6000 miles. Nothing was needed. Car drives amazing and beastly.

[Jadar]

Honestly it's not your plugs or the coils, but still gap them down to around .20.

I had a similar issue with my jb4 on my n55. It ran fine and then like a year later started acting the same way as yours did. I contacted terry at bms and he sent me a new board for like $100 bucks and I replaced it and it was fine after that.

Try that 1st before venturing out into replacing expensive parts like coils.

[Jadar]

Originally Posted by CaryTheLabelGuy

Ive been running the stock plugs. But I'm not running anything crazy and have no plans to.

Have you done any track days Cary? What is your current setup?

[CaryTheLabelGuy]

Originally Posted by Dejan_

Have you done any track days Cary? What is your current setup?

Honestly, my car is mostly stock.

M4 ZCP DCT with JB4 (stock ZCP tuning), BMS intakes, stock exhaust, stock downpipes, stock chargepipes, E40, running custom map 6 (additive) and less than 24psi.

On E40, my ZCP is running the maximum timing curve, pull after pull.

At less than 20psi, it breaks traction in 4th often. I have no need to run higher boost as this car pulls very strong with this setup and traction is already limited.

My philosophy is simple, why run more boost than you have to? This car runs phenomenally with this setup.

Here is a screenshot of a 3rd to 4th gear pull to see for yourself. The car was breaking traction all the way through 3rd and again in 4th at around 6200rpm. This is right at 20# of boost, as you can see.

Timing is maxed out on stock ZCP tuning. I was in S2 mode, which pulls a good bit of timing and closes the throttle plate between shifts. Had I been in S3, the throttle plate would have stayed open and you'd see less timing pull between gear changes, which produces a more violent gear change and can cause even more traction issues.

[Jadar]

Originally Posted by CaryTheLabelGuy

Honestly, my car is mostly stock.

M4 ZCP DCT with JB4 (stock ZCP tuning), BMS intakes, stock exhaust, stock downpipes, stock chargepipes, E40, running custom map 6 (additive) and less than 24psi.

On E40, my ZCP is running the maximum timing curve, pull after pull.

At less than 20psi, it breaks traction in 4th often. I have no need to run higher boost as this car pulls very strong with this setup and traction is already limited.

My philosophy is simple, why run more boost than you have to? This car runs phenomenally with this setup.

Here is a screenshot of a 3rd to 4th gear pull to see for yourself. The car was breaking traction all the way through 3rd and again in 4th at around 6200rpm. This is right at 20# of boost, as you can see.

Timing is maxed out on stock ZCP tuning. I was in S2 mode, which pulls a good bit of timing and closes the throttle plate between shifts. Had I been in S3, the throttle plate would have stayed open and you'd see less timing pull between gear changes, which produces a more violent gear change and can cause even more traction issues.

Yeah it definitely isn't hard for the s55 to break loose that rear end. It's just sweet how quick the car is even with Zcp HP bump.

I've been a believer since my younger American muscle days that more hp is not always the answer especially to having a faster car.

500rwhp is more then enough for the street.

I was just curious how you were setup.

[Sleeper]

Originally Posted by Dejan_

Yeah it definitely isn't hard for the s55 to break loose that rear end. It's just sweet how quick the car is even with Zcp HP bump.

I've been a believer since my younger American muscle days that more hp is not always the answer especially to having a faster car.

500rwhp is more then enough for the street.

I was just curious how you were setup.

+1. Even in fresh-out-of-the-factory mode, the F8x is severely tire limited. Wider, stickier tires is a very simple and potent upgrade just by itself.

[JoeyBananas]

Peak TQ & HP is same with JB4 right? ZCP, non ZCP? The ZCP Has different traction control?

[EBM4]

Originally Posted by CaryTheLabelGuy

Honestly, my car is mostly stock.

M4 ZCP DCT with JB4 (stock ZCP tuning), BMS intakes, stock exhaust, stock downpipes, stock chargepipes, E40, running custom map 6 (additive) and less than 24psi.

On E40, my ZCP is running the maximum timing curve, pull after pull.

At less than 20psi, it breaks traction in 4th often. I have no need to run higher boost as this car pulls very strong with this setup and traction is already limited.

My philosophy is simple, why run more boost than you have to? This car runs phenomenally with this setup.

Here is a screenshot of a 3rd to 4th gear pull to see for yourself. The car was breaking traction all the way through 3rd and again in 4th at around 6200rpm. This is right at 20# of boost, as you can see.

Timing is maxed out on stock ZCP tuning. I was in S2 mode, which pulls a good bit of timing and closes the throttle plate between shifts. Had I been in S3, the throttle plate would have stayed open and you'd see less timing pull between gear changes, which produces a more violent gear change and can cause even more traction issues.

Hey Cary,

So I have Pure Turbos and FBO with JB4 installed on map 2 from 2nd or 3rd gear full throttle as I approach redline the car feels and sounds like it is misfiring. I do not get any codes the car will not shift gears from 2nd to 3rd or 3rd to 4th during these events. Does this sound like the same thing the OP is talking about on his car. I'm 16k miles now and in stock plugs, I can log the car tomorrow if that helps, I am not very good with the JB4 so I am assuming on the app I start he log prior to flooring it in second and run through the gear change (if it changes gear). Thanks

[dmk08]

Originally Posted by JoeyBananas

Peak TQ & HP is same with JB4 right? ZCP, non ZCP? The ZCP Has different traction control?

No why would it be? Jb4 adds boost to increase power. Adds it the same on a zcp and std. so since zcp starts with more itll end with more. Plus the zcp tune fueling is much better for the higher maps.

[dmk08]

Originally Posted by EBM4

Hey Cary,

So I have Pure Turbos and FBO with JB4 installed on map 2 from 2nd or 3rd gear full throttle as I approach redline the car feels and sounds like it is misfiring. I do not get any codes the car will not shift gears from 2nd to 3rd or 3rd to 4th during these events. Does this sound like the same thing the OP is talking about on his car. I'm 16k miles now and in stock plugs, I can log the car tomorrow if that helps, I am not very good with the JB4 so I am assuming on the app I start he log prior to flooring it in second and run through the gear change (if it changes gear). Thanks

Post up a csv log. Need to look at your trims etc.

I always so my log runs in 3rd from 3000 to redline but I have manual so maybe 4th for you?