JB4 Maps on 93 Octane

[i3igpete]

Ignition timing in all cylinders except 3 are all super smooth. i wouldn't worry about this unless cyl 3 keeps having this problem, pull-to-pull variations are normal (remember knock is a stochastic event).

FF and WGDC look nice and aligned, no throttle closures.

Trims are momentarily high, but not a huge deal, you can deal with this by ramping boost up a little more slowly below ~4500. what is your current e-blend?

Overall looks great. you can probably raise boost if you wanted.

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[Gryph8n]

No E blend, just gasoline.

 

[ColonelAdama]

No E blend, just gasoline.

Good 93, log looks great.

 

[Gryph8n]

Thanks ColonelAdama, you have been super helpful. I appreciate you.

If default wastegate position is set at 0, I presume it defaults to baseline?…60? If fuel open loop is set at zero, what is the default?

Is the Boost drop 1st, 2nd and 3rd numbers by absolute total boost or additional boost? In other words if I enter 15 and extra boost is 4, then it defaults to total boost limit at that gear?

 

[ColonelAdama]

Thanks ColonelAdama, you have been super helpful. I appreciate you.

If default wastegate position is set at 0, I presume it defaults to baseline?…60? If fuel open loop is set at zero, what is the default?

Is the Boost drop 1st, 2nd and 3rd numbers by absolute total boost or additional boost? In other words if I enter 15 and extra boost is 4, then it defaults to total boost limit at that gear?

Default wastegate position is supposedly a "lag-fix" but even BMS doesn't mention it much because it hardly does anything. Default is 0. I have tried up to 50-60. I've heard after that, you can get a CEL. It was more made for N54,N55 cars that have pneumatic wastegates. Not electric like b58

Fuel open loop does nothing for b58. 0 is the default.

Boost drop is "reduction", as in the opposite of additive. Whatever target you have set will be subtracted by those numbers.

 

[Gryph8n]

Default wastegate position is supposedly a "lag-fix" but even BMS doesn't mention it much because it hardly does anything. Default is 0. I have tried up to 50-60. I've heard after that, you can get a CEL. It was more made for N54,N55 cars that have pneumatic wastegates. Not electric like b58

Fuel open loop does nothing for b58. 0 is the default.

Boost drop is "reduction", as in the opposite of additive. Whatever target you have set will be subtracted by those numbers.

ColonelAdama, I logged some 0-60mph pulls. Please see the logs.

https://datazap.me/u/gryph8n/log-1709077117?log=0&data=1-4

The first pull, I noted that my FF curve overshot my PWM curve in the beginning and lagged below late in higher rpms, so I adjusted my boost at those RPMs to match the curve better in the two subsequent runs. Looking at the graphs of my two later runs, the FF & PWM curves match perfectly. Shouldn’t that optimize my performance? However my 0-60mph times were slower for the two later runs? Am I missing something? Please help me understand this? Thanks

 

[ColonelAdama]

ColonelAdama, I logged some 0-60mph pulls. Please see the logs.

https://datazap.me/u/gryph8n/log-1709077117?log=0&data=1-4

The first pull, I noted that my FF curve overshot my PWM curve in the beginning and lagged below late in higher rpms, so I adjusted my boost at those RPMs to match the curve better in the two subsequent runs. Looking at the graphs of my two later runs, the FF & PWM curves match perfectly. Shouldn’t that optimize my performance? However my 0-60mph times were slower for the two later runs? Am I missing something? Please help me understand this? Thanks

0-60 runs aren't any good for reviewing logs. Need a 3rd or 4th gear pull from 2500 to redline, and ideally a shift into the next gear before letting off.

You can't accurately tune your FF curve without looking at the entire RPM range while you have full traction and no boost by gear (ie. 3rd gear+ in your case).

 

[Gryph8n]

0-60 runs aren't any good for reviewing logs. Need a 3rd or 4th gear pull from 2500 to redline, and ideally a shift into the next gear before letting off.

You can't accurately tune your FF curve without looking at the entire RPM range while you have full traction and no boost by gear (ie. 3rd gear+ in your case).

okay here are two more logs, pulls from 3rd gear to redline before shifting. Anything I can do to optimize power delivery curve?

https://datazap.me/u/gryph8n/log-1709139872?log=0&data=1-4

 

[i3igpete]

Trims and timing look great. You have throttle closures right at 5k that corresponds to your target curve ramping down, at the same time that FF is ramping up. You're basically asking the JB4 to do opposite things at the same time.

You can either change your duty bias to ramp up less aggressively, or change the boost target to be flatter above 5k. Either one should solve the throttle closure.

 

[Gryph8n]

So at 5000rpm and higher, I can keep boost levels the same and not taper off until 6500rpm? I had tapered due to concerns of overboost.

 

[i3igpete]

Overboost is an overloaded term, could you elaborate what you mean by overboost?

 

[Gryph8n]

the concern of having the boost levels going too high at higher rpm and overshooting the target boost and having the ECU cut power.

so my prior boost was at +4.1 psi @4500rpm-5000rpm with decrease at higher rpms.
5000 rpm = 4.1 psi
5500 = 3.7
6000 = 3.6
6500 = 3.0
7000 = 2.5

i3igpete you are suggesting that I just keep boost at 4.1 psi flat rather than tapering?

 

[ColonelAdama]

the concern of having the boost levels going too high at higher rpm and overshooting the target boost and having the ECU cut power.

so my prior boost was at +4.1 psi @4500rpm-5000rpm with decrease at higher rpms.
5000 rpm = 4.1 psi
5500 = 3.7
6000 = 3.6
6500 = 3.0
7000 = 2.5

i3igpete you are suggesting that I just keep boost at 4.1 psi flat rather than tapering?

In my opinion, you just need to drop duty bias at 5k by a bit until throttle closures stop dropping below ~80. Try something like 44 or 45 instead of the current 48.

Otherwise it is not far off from being perfect. @i3igpete, I don't think any drop in boost targets is needed. If anything, I see headroom for another +1 psi across the whole range.

 

[i3igpete]

overshooting the target boost and having the ECU cut power.

i3igpete you are suggesting that I just keep boost at 4.1 psi flat rather than tapering?

At the boost levels you're currently running, we're still in the throttle valve's command range, and fuel trims at the high end are nowhere near maxed. You're unlikely to hit fuel cut/limp mode.

But, yes, I'm suggesting that you can run more boost at 5k (and above) if you wanted to, and the effect is that the throttle would stay open. Or, you can back off the duty bias in the 5k range.

Personally, I prefer to counteract the DME_BT's default taper at the high end by requesting peak boost very near redline. This is personal preference, of course.

If anything, I see headroom for another +1 psi across the whole range.

Agree

 

[Gryph8n]

In my opinion, you just need to drop duty bias at 5k by a bit until throttle closures stop dropping below ~80. Try something like 44 or 45 instead of the current 48.

Otherwise it is not far off from being perfect. @i3igpete, I don't think any drop in boost targets is needed. If anything, I see headroom for another +1 psi across the whole range.

how do these settings look?

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