SUPRA ULTIMATE B58 JB4 GUIDE AND LOG REVIEW (V1)

[ColonelAdama]

@ColonelAdama

Still looks like a bit too much ethanol. You can try bumping up FF by a few to see if that helps at all, but likely you need to dilute with more 93. Try to stick to 3 gal max. JB4 cars typically struggle with trims past E30. Trims at 49 for multiple consecutive datapoints is no good, risk of AFR going lean, CEL, JB4 safety triggered, etc.

Sponsored

 

[Carbonfibah]

Do you think I was making peak power at that level of e and I am going to drop off power by diluting more(I know it is more important than power just wondering what to expect? @ColonelAdama

 

[ColonelAdama]

Do you think I was making peak power at that level of e and I am going to drop off power by diluting more(I know it is more important than power just wondering what to expect? @ColonelAdama

your timing was fine, so as long as it still holds up after diluting, no power lost. Yes, you will lose power if you dilute too much and timing starts to suffer from low octane.

 

[swrdply400mrelay]

@ColonelAdama

With the JB4 PI kit, would you still run into fueling issues if you went with a stuffed or hybrid turbo?

 

[ColonelAdama]

@ColonelAdama

With the JB4 PI kit, would you still run into fueling issues if you went with a stuffed or hybrid turbo?

probably not, BMS has done it. I remember seeing that it does take some effort to dial in though

 

[Dven11]

@ColonelAdama Can you help me review my log?

https://datazap.me/u/dven11/log-1724202986?log=0&data=1-4-5-6-8-9-11-14-23-25-26-27-28-29

 

[ColonelAdama]

@ColonelAdama Can you help me review my log?

https://datazap.me/u/dven11/log-1724202986?log=0&data=1-4-5-6-8-9-11-14-23-25-26-27-28-29

Its not bad, but boost curve is kinda weird. WGDC tuning likely needed. What downpipe on the car?

 

[i3igpete]

Any time WGDC is offset by 5 or more from the FF curve, that is a region where you should adjust duty bias, since the PID control can only +/- ~8. That is why you're barely boosting over stock.

Try this:

duty_15

duty_20

duty_25

duty_30

duty_35

duty_40

duty_45

duty_50

duty_55

duty_60

duty_65

duty_70

old

50​

50​

50​

50​

50​

50​

50​

50​

50​

50​

50​

50​

new

50​

50​

50​

50​

50​

50​

52​

55​

55​

57​

57​

57​

 

[Dven11]

Its not bad, but boost curve is kinda weird. WGDC tuning likely needed. What downpipe on the car?

Whoops, sorry, I completely forgot the mods:

HKS Intake
Charge Pipe
VRSF Catless Down Pipe
VR Exhaust

Any time WGDC is offset by 5 or more from the FF curve, that is a region where you should adjust duty bias, since the PID control can only +/- ~8. That is why you're barely boosting over stock.

Try this:

duty_15

duty_20

duty_25

duty_30

duty_35

duty_40

duty_45

duty_50

duty_55

duty_60

duty_65

duty_70

old

50​

50​

50​

50​

50​

50​

50​

50​

50​

50​

50​

50​

new

50​

50​

50​

50​

50​

50​

52​

55​

55​

57​

57​

57​

Super helpful! Ok I will try that.

 

[Dven11]

@i3igpete @ColonelAdama

Ok I made the changes that Pete suggested:

https://datazap.me/u/dven11/log-1724293411?log=0&data=1-4-5-6-8-11-14-18-20-25-26-27-28-29

The more I look at the graphs and read up, the more I start understanding them. Who knew.

 

[i3igpete]

keep going, here's the diff between wgdc and ff for both pulls:

Draw a line through the middle of those two curves, and add it to your last duty bias curve. Note that if the JB4 isn't doing anything (during part throttle or spool up) then both curves just report 50.

Not a coincidence that it's starting to look like the table in adam's first post

	duty_15	duty_20	duty_25	duty_30	duty_35	duty_40	duty_45	duty_50	duty_55	duty_60	duty_65	duty_70
old	50	50	50	50	50	50	50	50	50	50	50	50
new	50	50	50	50	50	50	52	55	55	57	57	57
new2	47	47	47	47	47	50	56	59	61	61	63	63

 

[ColonelAdama]

Not a coincidence that it's starting to look like the table in adam's first post

duty_15	duty_20	duty_25	duty_30	duty_35	duty_40	duty_45	duty_50	duty_55	duty_60	duty_65	duty_70
32	32	32	32	35	36	39	48	55	57	62	62

FF= 35~40 ballpark But its good to see the process as a demonstration

catless and hi flow dp cars have a big drop off of duty under 5k typically.

 

[ColonelAdama]

@i3igpete
The tricky part of this WGDC tuning is that, unfortunately, there is usually more to it than syncing up the FF/WGDC curves.

Remember that the B58 is torque targeting, so when FF is too high, sometimes the car will just take the extra boost, consider it as cylinder overfill and reduce timing to stay under the torque target. Its not ideal running conditions and can overstress the turbo and just blow hot air. I have seen cars on Map 1 running 23 psi with horrible timing on 93 octane.

more info: https://ecutek.atlassian.net/wiki/spaces/SUPPORT/pages/170557464/B58+Tuning+Guide

So the best way to mitigate this, imo, is do a Map 0 log and figure out what ecu_psi /dme_bt range the car wants to run at. Your goal with JB4 is to adjust FF and duty so that ecu_psi / dme_bt curves look as similar to the Map 0 log as possible.

ecu_psi is ideally 1 psi below dme_bt (any closer is throttle closures)
dme_bt should usually be in the 12-17psi range depending on conditions. (cylinder fill ~100%, or whatever cylinder fill desired is)

This is a B48, but is demonstrating exactly what I mean. 23.5 psi on Map 1. No timing. But the boost control and WGDC stuff would appear to be a good fit right? I would start dropping FF on this car, and you'll find that dme_bt will drop too.

https://datazap.me/u/coloneladama/log-1724333400?log=0&data=1-2-3-4-8-11-15-20&zoom=61-144

 

[i3igpete]

Regarding the last log, I would argue that cause and effect might be getting mixed up. If knock is detected during the spool up phase, then that would disable ignition advance because combustion is already unpredictable. (The DME can't differentiate between pre-ignition or detonation, so it just avoids timing advance either way.)

The DME goes for increased boost because that's the only knob it has left to meet the torque target.

 

[ColonelAdama]

Regarding the last log, I would argue that cause and effect might be getting mixed up. If knock is detected during the spool up phase, then that would disable ignition advance because combustion is already unpredictable.

The DME goes for increased boost because that's the only knob it has left to meet the torque target.

That's a viable theory. Notice there are 2 logs in my link. The second is with an E blend and no improvement whatsoever with timing. I think it is because cylinder fill % is just too high.

Sponsored