JB4 Maps on 93 Octane

[Gryph8n]

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.

So boost is at chargepipe and boost 2 is at manifold. In theory boost 2 smooths spikes in pressure and is what “matters”. So the boost curve could be a little smoother by upping the psi a few points at lower rpms?…but pretty close to optimal now.

Sponsored

 

[ColonelAdama]

So boost is at chargepipe and boost 2 is at manifold. In theory boost 2 smooths spikes in pressure and is what “matters”. So the boost curve could be a little smoother by upping the psi a few points at lower rpms?…but pretty close to optimal now.

Yes.

You can certainly give it a try. That's what Map 4 does, just with absolute.

The issue is that the stock map on the DME doesn't really kick up the boost targets (dme_BT/ecu_psi) till around 4.5-5k. So you can run into fuel limits quicker under 4.5/5k when pushing more boost.

in other words, there's more fuel headroom 5k+.

 

[Gryph8n]

Yes.

You can certainly give it a try. That's what Map 4 does, just with absolute.

The issue is that the stock map on the DME doesn't really kick up the boost targets (dme_BT/ecu_psi) till around 4.5-5k. So you can run into fuel limits quicker under 4.5/5k when pushing more boost.

in other words, there's more fuel headroom 5k+.

on the first run, I increased psi at 3500 rpm to 3.7 instead of 3.6. But got boost pressure spike at the end of the curve but not on boost 2 curve.

Second run, returned to 3.6 @3500 and the spike is gone.

Third run, tried increasing psi at 4500rpm from 4.6 to 4.7 but again got pressure spike at end of boost curve.

I presume run 1 & 2 or not ideal with spike of boost curve at the end even though boost 2 curve is smooth and throttle doesn’t correct? This is a good indicator that my pressure curve is optimized?

I understand what you are saying with map 4. Between this thread and your other ultimate JB4 guide, you have provided so much valuable information. Basically everything that is needed for someone to run and optimized their map 2, 4 and 6.

 

[i3igpete]

i would not read too much into a cause and effect with such small changes. the dme itself can vary boost targets (and therefore the control strategy to achieve those targets) by 2 psi from pull to pull within minutes of each other.

 

[ColonelAdama]

on the first run, I increased psi at 3500 rpm to 3.7 instead of 3.6. But got boost pressure spike at the end of the curve but not on boost 2 curve.

Second run, returned to 3.6 @3500 and the spike is gone.

Third run, tried increasing psi at 4500rpm from 4.6 to 4.7 but again got pressure spike at end of boost curve.

I presume run 1 & 2 or not ideal with spike of boost curve at the end even though boost 2 curve is smooth and throttle doesn’t correct? This is a good indicator that my pressure curve is optimized?

I understand what you are saying with map 4. Between this thread and your other ultimate JB4 guide, you have provided so much valuable information. Basically everything that is needed for someone to run and optimized their map 2, 4 and 6.

Yeah your boost control is fine. I would just be fine tuning your stuff at this point and watching timing since you're over 20 psi on 93.

If your timing sucks, you'll lose more power than the boost is worth.

 

[Gryph8n]

Running a different fuel source at high altitude. Had to adjust my boost pressure down. How do these logs look? What happened to my WGDC the first pull? Thanks

https://datazap.me/u/gryph8n/log-1709770537?log=0&data=1-4

 

[totalone]

Damn some work was put into this,

I will be copying your 21PSi target to see how my car will react to it. he only concern I have with this is cold temps now. Summer will be much hotter and I wonder how will extra boost behave with not such dense air.

 

[ColonelAdama]

Running a different fuel source at high altitude. Had to adjust my boost pressure down. How do these logs look? What happened to my WGDC the first pull? Thanks

https://datazap.me/u/gryph8n/log-1709770537?log=0&data=1-4

map is too hot up top. timing is horrible. 5k+ boost needs to be dropped.

why not try map 2 and see how timing looks then? if its still no good, then you'll need better fuel.

 

[Gryph8n]

Yes I’m finding out that fuel source is important. Just limited in what is available close to me. So for 5k+ on this map, maybe go to not more than 4.2psi and taper to 3.0 by 7k or just keep flat?

 

[Gryph8n]

map is too hot up top. timing is horrible. 5k+ boost needs to be dropped.

why not try map 2 and see how timing looks then? if its still no good, then you'll need better fuel.

looking like my map 2 is okay? What psi ramp up do you recommend?

https://datazap.me/u/gryph8n/log-1710201307?log=0&data=1-4

 

[Gryph8n]

I re-ran the map 6 values listed above with better fuel. https://datazap.me/u/gryph8n/log-1710202479?log=0&data=1-4

 

[ColonelAdama]

I re-ran the map 6 values listed above with better fuel. https://datazap.me/u/gryph8n/log-1710202479?log=0&data=1-4

Looks pretty good. See if turning up autoboost redux improves your shifts. Boost could be a bit smoother on the shift from the log.

 

[Gryph8n]

So I ran some 0-60mph times. Could someone look at run 2 of this log? Is it even possible that I got a sub-3 second run? Or did JB4 glitch? I realize that this isn’t as accurate as a draggy. Thanks

https://datazap.me/u/gryph8n/log-1710283281?log=0&data=1-4

 

[ColonelAdama]

So I ran some 0-60mph times. Could someone look at run 2 of this log? Is it even possible that I got a sub-3 second run? Or did JB4 glitch? I realize that this isn’t as accurate as a draggy. Thanks

https://datazap.me/u/gryph8n/log-1710283281?log=0&data=1-4

Yeah I have no idea how reliable that 0-60 actually is so don't take it so seriously.

Logs look pretty good. Run 2 had the cleanest shifting. Others boost spiked a bit on shift, so I recommend turning up autoboost redux till Boost2 stays relatively smooth through the shift.

ie, turn it up by 10 and see if it improves.

 

[Gryph8n]

My autoboost redux is already at 70, need to go higher to 75?

Sponsored