JB4 boost readings still seem low

[Terry@BMS]

EWG opens up a lot of possibilities, especially so for larger turbos!

 

[Tonkabob]

Good to hear. I'm really loving the new EWG control now that I mostly have it working. That combined with the new boost scaling means we'll probably see some 25psi logs soon lol. Don't think there is much more power to be had beyond "20psi" with the new scaling but never hurts to keep trying.

Yeah hit 26 psi this morning!
On the new scale i think 22-24 still has some added power.

 

[xot1]

EWG opens up a lot of possibilities, especially so for larger turbos!

That is my long term plan. I hope I can still use JB4 with a back end flash on hybrid turbos.

Yeah hit 26 psi this morning!
On the new scale i think 22-24 still has some added power.

26

 

[Terry@BMS]

Collected a little data today... Found a problem in the firmware and didn't have the software handy to fix it so will need to pick it back up later. But, so far the data mirrors my previous testing.

1) Boost > 20psi, minimal gains. Especially top end boost where we need it for track benefits.
2) Leaning out AFR does add top end power at the expense of stability/safety.


20psi vs. 23psi peak:


23psi peak but with a much leaner AFR (like, 14:1 at peak HP!)

 

[xot1]

Collected a little data today... Found a problem in the firmware and didn't have the software handy to fix it so will need to pick it back up later. But, so far the data mirrors my previous testing.

1) Boost > 20psi, minimal gains. Especially top end boost where we need it for track benefits.
2) Leaning out AFR does add top end power at the expense of stability/safety.


20psi vs. 23psi peak:
View attachment 36351

23psi peak but with a much leaner AFR (like, 14:1 at peak HP!)
View attachment 36352
View attachment 36353 View attachment 36354

Do you have a theory to explain the higher torque at 20psi?
How is your test car on the exhaust side? Is it stock?

 

[HerbieTheCar]

Collected a little data today... Found a problem in the firmware and didn't have the software handy to fix it so will need to pick it back up later. But, so far the data mirrors my previous testing.

1) Boost > 20psi, minimal gains. Especially top end boost where we need it for track benefits.
2) Leaning out AFR does add top end power at the expense of stability/safety.


20psi vs. 23psi peak:
View attachment 36351

23psi peak but with a much leaner AFR (like, 14:1 at peak HP!)
View attachment 36352
View attachment 36353 View attachment 36354

What Map are these tests done on?

 

[Tonkabob]

This looks like a custom map with +10 PSI and using the new waste gate controls. WMI also?

At 22 PSI and 5K RPM you are only pulling like 7-8 timing advance while in my log i'm at 12.5 adv. At 5400, peak HP you are up to 11. More power to be had there.

But at 6000 you have 15 timing in both and a few more PSI in one and the HP and TQ are the same which is odd.

Thanks for sharing, great info and exciting how much boost you can hold at RPM now.

 

[Toddasaurus]

EWG opens up a lot of possibilities, especially so for larger turbos!

Do you know if the wastegates are open during launch control? I wonder if we could build a little boost if they're fully closed we could actually do some brake boosting in LC...?

 

[Terry@BMS]

What Map are these tests done on?

Map6 and the E85 autotuning map. Running car on 40% E85. Ran CPI to keep fuel pressure level as boost went up on these specific runs but on another round of testing where I test it leaner (the 465 chart) CPI was disabled.

 

[Terry@BMS]

But at 6000 you have 15 timing in both and a few more PSI in one and the HP and TQ are the same which is odd.

Thanks for sharing, great info and exciting how much boost you can hold at RPM now.

WGDC is the offset to dutycycle. The higher it goes the more wastegate dutycycle is being added. The JB4 also datalogs actual wastegate dutycycle now through the same connections it uses to adjust it.

I've hit 25-26psi on the road with clean timing so expected to see good things on the dyno, and while there was some midrange power to be had, the top end didn't budge. Maybe the primary downpipes are just a limiting factor now? I don't have a sensor to measure turbine back pressure on this car to test the pressure ratio.

 

[Terry@BMS]

Do you know if the wastegates are open during launch control? I wonder if we could build a little boost if they're fully closed we could actually do some brake boosting in LC...?

Yes I think we'll be able to improve boost at the launch both in LC and brake boosting applications now with this EWG control, although our specific car is RWD and traction limited, so we'll need to recruit some AWD cars who don't mind risking breaking drive train parts.

 

[Terry@BMS]

Do you have a theory to explain the higher torque at 20psi?
How is your test car on the exhaust side? Is it stock?

I outlined my theory in another post but basically excessive back pressure preventing top end gains is my suspicion. Likely, due to the small factory turbine. Catless primaries may extend the top end power band a bit in this situation.

 

[Tonkabob]

Could it be heat as well? 22 psi at 6k is alot more turbine speed than 22 psi at 4k.
Timing is good at 6k.

 

[Thorne]

Can you share graphs showing boost and share csv? Something looks to be restricting the top end... One thing that I don't get is your showing numbers now that don't agree with you jb4 site...

 

[Terry@BMS]

Could it be heat as well? 22 psi at 6k is alot more turbine speed than 22 psi at 4k.
Timing is good at 6k.

In my experience it's usually what we call exhaust back pressure. Basically the ratio of pressure in the turbine housing relative to the boost pressure. If it's more than 2:1 then you stop making more power as you continue to raise boost. The "fix" is usually a larger or higher flowing turbine. The correct diagnostic test is to attach a pressure sensor to the turbine and feed that in to the JB4 to log along side boost. I'll see what I can do, requires to drill/tap the exhaust side of the housing which isn't always practical due to turbo placement.

 

[Terry@BMS]

Can you share graphs showing boost and share csv? Something looks to be restricting the top end... One thing that I don't get is your showing numbers now that don't agree with you jb4 site...

I'm purposely not posting all of the information I've gathered, just what is relevant to this discussion we're having on boost pressure. I'm still running a business here, after all.

 

[Thorne]

 

[HerbieTheCar]

Map6 and the E85 autotuning map. Running car on 40% E85. Ran CPI to keep fuel pressure level as boost went up on these specific runs but on another round of testing where I test it leaner (the 465 chart) CPI was disabled.

Would there be any increases for users who are only using Map 1 or Map 2?

 

[Terry@BMS]

Would there be any increases for users who are only using Map 1 or Map 2?

The discussion in this thread is intended for modified max power guys so won't apply to someone just running map1 or map2.

 

[xot1]

I outlined my theory in another post but basically excessive back pressure preventing top end gains is my suspicion. Likely, due to the small factory turbine. Catless primaries may extend the top end power band a bit in this situation.

That would make sense. Can't it also be the exhaust getting too hot?