SUPRA ULTIMATE B58 JB4 GUIDE AND LOG REVIEW (V1)

[FLtrackdays]

It's possible that the JB4 just reverted to Map 0 if any safety was tripped. Whether it be fueling, boost, knock related. I can see if it was in a log.

Next time you're on an empty highway ramp, just punch it in 3rd for a log. No need to wait for a track day and can still avoid speeding too much.

Sounds good! Map 0 (off), keep it in 3rd gear, hit the log button, floor it, when the car and temps are hot outside about 3 times (logs)? Ideally, I’d like to replicate when the car is extra toasty, like when it happens on track. Or does that not matter?

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[ColonelAdama]

Sounds good! Map 0 (off), keep it in 3rd gear, hit the log button, floor it, when the car and temps are hot outside about 3 times (logs)? Ideally, I’d like to replicate when the car is extra toasty, like when it happens on track. Or does that not matter?

Just take logs across the year and send em for review. Usually the car adapts on its own if you are using additive maps. 3rd gear, and do one Map 0 and Map 1.

 

[ColonelAdama]

Yall... I think I finally found the cause of MT issues.... Yes, I have talked about the solutions, but I spent a while researching today and one theory lines up with every MT log I've ever seen.

Behold: Injection Monitoring - A new feature for B58s, not in prior N55s/S55s.

Injection monitoring function actively checks the status of the high pressure fuel system, both pump and injection, and can lower the cylinder fill limit to prevent either maxing the pump or available injection window.

This connects Terry's theory of IPW (injector pulse width) exceeding a defined limit, along with my theory that there is a torque limit. Torque, of course, is directly related to cylinder fill.

The real truth appears to be that a "torque limit" is put in place when injector pulse width limits are exceeded. This is pretty much caused by too much ethanol or too high of boost targets on the JB4, but in the case of an MT car, VERY easy to exceed.

Also supports why some people experience dme_Bt drops with the new FP upgrade - definitely tripping the injection monitoring flag. "The high pressure fuel pump can be considered at it’s limit if either the maximum angle (typically 126°) is reached, the fuel pressure drops far enough below the target, or if the mass flow rate of the fuel reaches the calculated mass flow rate of the pump. " Either of these two in bold are easy to trip when you are spoofing a low pressure value to the DME. Even though you are not really hitting the pump limit.

Shoutout @a90Omen for the revelation based on your no O2 sensor log ? I found that the MT boost issues are directly tied to the closed loop fueling model.

"When the conditions to start limiting are met, the ECU starts to drop the cylinder fill limit (DME_BT) until the fuel pump is back within spec. It does this by incrementing the limit down quite rapidly, but up again quite slowly. "

Sound familiar?

I can't say why MT cars have their monitoring more sensitive, but I would assume just because the DME has less control over vehicle operation/boost/shifting.

 

[razorlab]

Yall... I think I finally found the cause of MT issues.... Yes, I have talked about the solutions, but I spent a while researching today and one theory lines up with every MT log I've ever seen.

Behold: Injection Monitoring - A new feature for B58s, not in prior N55s/S55s.

Injection monitoring function actively checks the status of the high pressure fuel system, both pump and injection, and can lower the cylinder fill limit to prevent either maxing the pump or available injection window.

This connects Terry's theory of IPW (injector pulse width) exceeding a defined limit, along with my theory that there is a torque limit. Torque, of course, is directly related to cylinder fill.

The real truth appears to be that a "torque limit" is put in place when injector pulse width limits are exceeded. This is pretty much caused by too much ethanol or too high of boost targets on the JB4, but in the case of an MT car, VERY easy to exceed.

Also supports why some people experience dme_Bt drops with the new FP upgrade - definitely tripping the injection monitoring flag. "The high pressure fuel pump can be considered at it’s limit if either the maximum angle (typically 126°) is reached, the fuel pressure drops far enough below the target, or if the mass flow rate of the fuel reaches the calculated mass flow rate of the pump. "


Shoutout @a90Omen for the revelation based on your no O2 sensor log ? I found that the MT boost issues are directly tied to the closed loop fueling model.

"When the conditions to start limiting are met, the ECU starts to drop the cylinder fill limit (DME_BT) until the fuel pump is back within spec. It does this by incrementing the limit down quite rapidly, but up again quite slowly. "

Sound familiar?

That is when the SOI hit over 400. No way a stock turbo B58 is hitting over 400 SOI

Mine doesn't even hit that until high rpm 6500rpm+ at 28+ PSI on a Pure 700

EDIT: My bad, I thought that was the link to EOI and SOI since you mentioned injector IPW. That is HPFP angle limit at 126, not injector IPW or anything. Stock turbo can def hit that in lower/mid rpm. I don't see how this is MT specific though?

 

[ColonelAdama]

Stock turbo can def hit that in lower/mid rpm.

This is just supplementing my hypothesis. The issue is rare above 5500.

 

[razorlab]

This is just supplementing my hypothesis. The issue is rare above 5500.

Yes, HPFP demand goes down as RPM rise since it's cam driven. It's the HPFP, not the injectors.

You could log via MG Flasher app (free to log with a free account) and log HPFP angle and see if it's really happening. Again though, this isn't MT specific.

 

[razorlab]

@ColonelAdama

Here is an example of load limitation created by injector SOI (Fuel Injector Angle Start) going over 400. Notice that load limit logging item (top light blue plot) drops as soon as SOI crosses over into 400+ and the Fill Limit Flag "8" gets tripped.

 

[ColonelAdama]

Again though, this isn't MT specific.

I promise something is configured differently. Even Manual S58s have the same issue.

 

[razorlab]

I promise something is configured differently. Even Manual S58s have the same issue.

Sure, but it isn't those tables mentioned in that Ecutek article you linked. Those tables are the same between MT and AT.

 

[ColonelAdama]

Sure, but it isn't those tables mentioned in that Ecutek article you linked. Those tables are the same between MT and AT.

Hm, so you checked Load limit adjustment rates on each ROM?

 

[razorlab]

Hm, so you checked Load limit adjustment rates on each ROM?

Yup. Can you log via MG Flasher app to really see what is happening? Could get you closer to what it might be.

 

[ColonelAdama]

Yup. Can you log via MG Flasher app to really see what is happening? Could get you closer to what it might be.

I am pretty sure the JB4 disables when OBD is unplugged, so not really sure how log MG flasher. I guess theoretically you could try with a JB+ or other piggyback.

 

[razorlab]

I am pretty sure the JB4 disables when OBD is unplugged, so not really sure how log MG flasher. I guess theoretically you could try with a JB+ or other piggyback.

Does it? Are you sure? I thought the OBD2 connection was just for logging? I would hope so since their sample rate is atrocious. I wouldn't depend on anything with that rate.

 

[a90Omen]

Yall... I think I finally found the cause of MT issues.... Yes, I have talked about the solutions, but I spent a while researching today and one theory lines up with every MT log I've ever seen.

Behold: Injection Monitoring - A new feature for B58s, not in prior N55s/S55s.

Injection monitoring function actively checks the status of the high pressure fuel system, both pump and injection, and can lower the cylinder fill limit to prevent either maxing the pump or available injection window.

This connects Terry's theory of IPW (injector pulse width) exceeding a defined limit, along with my theory that there is a torque limit. Torque, of course, is directly related to cylinder fill.

The real truth appears to be that a "torque limit" is put in place when injector pulse width limits are exceeded. This is pretty much caused by too much ethanol or too high of boost targets on the JB4, but in the case of an MT car, VERY easy to exceed.

Also supports why some people experience dme_Bt drops with the new FP upgrade - definitely tripping the injection monitoring flag. "The high pressure fuel pump can be considered at it’s limit if either the maximum angle (typically 126°) is reached, the fuel pressure drops far enough below the target, or if the mass flow rate of the fuel reaches the calculated mass flow rate of the pump. " Either of these two in bold are easy to trip when you are spoofing a low pressure value to the DME. Even though you are not really hitting the pump limit.

Shoutout @a90Omen for the revelation based on your no O2 sensor log ? I found that the MT boost issues are directly tied to the closed loop fueling model.

"When the conditions to start limiting are met, the ECU starts to drop the cylinder fill limit (DME_BT) until the fuel pump is back within spec. It does this by incrementing the limit down quite rapidly, but up again quite slowly. "

Sound familiar?

I can't say why MT cars have their monitoring more sensitive, but I would assume just because the DME has less control over vehicle operation/boost/shifting.

It’s insane to me that my mindless mistake led to this… Let me know what sensor you want me to disconnect next and I’ll give it a shot ?

 

[i3igpete]

Does it? Are you sure? I thought the OBD2 connection was just for logging? I would hope so since their sample rate is atrocious. I wouldn't depend on anything with that rate.

When you unplug it loses input parameters of RPM/gear, so it goes into a failover version of map 1 without WG control. Just a constant offset to the pressure sensor at all times, similar to JB plus.

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