JB4 Maps on 93 Octane

[ColonelAdama]

try something like this. It should be a little peppier than Map 2.

map6_15	map6_20	map6_25	map6_30	map6_35	map6_40	map6_45	map6_50	map6_55	map6_60	map6_65	map6_70
1.0	1.5	2.0	2.5	3.5	4.0	4.5	5.0	5.0	4.5	3.5	3.0

if it rounds any of those targets by a tenth, don't worry about it. JB4 has tendency to do that.

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.

I did taper these targets but if they look good still, we can try it without the taper on the top end.

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[Gryph8n]

try something like this. It should be a little peppier than Map 2.

map6_15	map6_20	map6_25	map6_30	map6_35	map6_40	map6_45	map6_50	map6_55	map6_60	map6_65	map6_70
1.0	1.5	2.0	2.5	3.5	4.0	4.5	5.0	5.0	4.5	3.5	3.0

if it rounds any of those targets by a tenth, don't worry about it. JB4 has tendency to do that.



I did taper these targets but if they look good still, we can try it without the taper on the top end.

https://datazap.me/u/gryph8n/log-1709165453?log=0&data=1-4

new logs with changes. Then tried two runs at the end without taper but appears that has dropped timing (not throttle)?

 

[ColonelAdama]

https://datazap.me/u/gryph8n/log-1709165453?log=0&data=1-4

new logs with changes. Then tried two runs at the end without taper but appears that has dropped throttle?

whatever settings you ran for the first pull in that log is what you should stick with. last pulls in the log are too much boost and timing drops.

turn down duty bias a little 6.5k-7k too

 

[i3igpete]

agree. last few pulls the throttle looks great but timing goes down. back off boost a bit and compensate with lower duty bias to keep throttle open.

 

[Gryph8n]

These were my settings for the runs before dropped timing. I posted it for future reference for readers. I will turn down duty bias at 6500 and 7000 from 62 down to 60. Thanks again.

 

[ColonelAdama]

These were my settings for the runs before dropped timing. I posted it for future reference for readers. I will turn down duty bias at 6500 and 7000 from 62 down to 60. Thanks again.

Yeah, ~20 psi is about right for good 93 octane, and to be able to have great timing. If you make any changes, make sure they're smaller adjustments at this point.

 

[Gryph8n]

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.

Here is an illustration of i3igpete’s astute observation in a screen shot, since logs won’t always be available in links for future use. Circled in blue. Happens right at 4940 rpms.

 

[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.

 

[Gryph8n]

Throttle closures at 5000rpm. First graph before correcting duty bias. 2nd graph after correcting duty bias. ColonelAdama was spot on.

 

[Gryph8n]

Help me understand what is happening here at 2800-3100rpm when the throttle drops way down before maxing out. Is that a function of the turbo spooling up to speed and building boost? What is happening with the engine at this time?

 

[ColonelAdama]

Help me understand what is happening here at 2800-3100rpm when the throttle drops way down before maxing out. Is that a function of the turbo spooling up to speed and building boost? What is happening with the engine at this time?

Normal. Throttle is just managing the boost as it transitions from spool to steady state.

 

[Gryph8n]

I went back and adjusted boost at 6500rpm from 3.6 up to 3.7 but got throttle correction, see graph with blue circle. That pressure spike at the end is an indication of? So I’m thinking that I’m optimized for higher rpm range.

https://datazap.me/u/gryph8n/log-1709228529?log=0&data=1-4

the 2nd run, I adjusted psi back down to 3.6 and no throttle correction. But noticed the dip in pressure curve at lower rpms, circled in orange. Is there any room to optimize it there? Increase psi a few points or will that just mess up the whole curve?

 

[ColonelAdama]

That pressure spike at the end is an indication of?

throttle blade closing when you let off and boost building up in charge pipe for a moment

But noticed the dip in pressure curve at lower rpms, circled in orange. Is there any room to optimize it there?

its not so much a dip, rather that there's just a spike on transition from spool to steady state. DME just doesn't want to run as much boost under 4.5k. normal

it may help to look at Boost 2 (post throttle) to get a better idea of how smooth the power delivery is.

 

[Gryph8n]

throttle blade closing when you let off and boost building up in charge pipe for a moment


its not so much a dip, rather that there's just a spike on transition from spool to steady state. DME just doesn't want to run as much boost under 4.5k. normal

it may help to look at Boost 2 (post throttle) to get a better idea of how smooth the power delivery is.

boost 2 looks to me to match up to pre-boost curve. How does looking at boost 2 vs boost

help?

 

[ColonelAdama]

boost 2 looks to me to match up to pre-boost curve. How does looking at boost 2 vs boost

help?

Do you see that Boost2 does not show the spike at spool-to-steady state transition? right at boost threshold. should mellow out any spikes over/near target.

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