SUPRA ULTIMATE B58 JB4 GUIDE AND LOG REVIEW (V1)

[i3igpete]

Evening everyone!

Something weird is going on, you're underboosting by quite a bit (requesting +5 but only getting +1). the PID seems to not add anything to your FF curve despite being on and set to 20. Auto shift redux is non-zero, so I don't think it's the MT logic kicking in.

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[ColonelAdama]

Something weird is going on, you're underboosting by quite a bit (requesting +5 but only getting +1). the PID seems to not add anything to your FF curve despite being on and set to 20. Auto shift redux is non-zero, so I don't think it's the MT logic kicking in.

V28+ has no shift redux, but MTs don't have it anyway. I am actually testing MT shift redux with Terry this week.

You are looking at dme_bt, not ecu_psi. MTs need to underboost. ecu_psi+target=boost

 

[i3igpete]

Right, however,

This is a hard equation as the returned variable (and is always true):
target - boost = ecu_psi

and this is a targeting equation:
dme_bt + target < boost - 1psi

 

[ColonelAdama]

and this is a targeting equation:
dme_bt + target < boost - 1psi

yeah for the DME's PID on AT cars, no such logic in JB4.

Look at calc_tq, he is at the torque target the entire pull

ecu_psi technically 2+ psi below dme_bt, calc torque is still at target. MTs are weird dude lol. Given Aux3 (max 80), the turbo is at 91% WGDC total and shows slight oscillating behavior which would indicate its at its desired target.

 

[i3igpete]

Huh, is that aux3 being raw ewg duty cycle a new thing?

 

[ColonelAdama]

Huh, is that aux3 being raw ewg duty cycle a new thing?

yeah, I think V30+. 100% WGDC is Aux3=80 for whatever reason.

Nice to have!

 

[Thatpartsguy]

Both look fine to me. If you have a dragy or something you can verify which is faster. Map 6 is only 1 psi more so it shouldn't be anything drastic anyway.

Pardon me for the potentially stupid question, but it looks like its pulling lots of timing on map 6 and not on map 2 what parameter is tripping to do this?

 

[ColonelAdama]

Pardon me for the potentially stupid question, but it looks like its pulling lots of timing on map 6 and not on map 2 what parameter is tripping to do this?

I do not see any significant timing pull on either map. Remember Ign2-6 are the corrections on this firmware.

 

[Thatpartsguy]

I do not see any significant timing pull on either map. Remember Ign2-6 are the corrections on this firmware.

Ok so if I'm understanding correctly ign2-6 would spike if timing was pulled?

 

[ColonelAdama]

Ok so if I'm understanding correctly ign2-6 would spike if timing was pulled?

Yes

 

[vlad]

I'm still sometimes getting throttle closures around 3.2-3.5K RPM. The interesting thing is that I get throttle closures even on map 0. Today out of 4 runs on map 1, the first 2 had closures and the last 2 didn't.

Some background:

• '24 auto.
• AA high flow cat, otherwise stock.
• 3K ft above sea level.
• 91 octane.
• Map 1.

FF at 40.

Current settings:

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	32	32	39	48	55	57	62	62

Today's log on map 1. First 2 runs through 3rd gear only (both show throttle closures, on the second run I had to stop early for traffic), last 2 runs through 3rd and 4th gears with no closures.

Log from 9/28 on map 0 showing throttle closures around 3.4-3.5K RPM.

Is there anything that can be adjusted to prevent this?

 

[razorlab]

The interesting thing is that I get throttle closures even on map 0.

OEM mapping uses throttle as part of the boost control strategy. Normal.

 

[vlad]

OEM mapping uses throttle as part of the boost control strategy. Normal.

So if the OEM mapping closes the throttle like this, how can we expect to not have this while running a JB4? In this thread people have mentioned that the throttle shouldn't go below 80% with the JB4 while the pedal is at 100%, but I was seeing 47% on map 0. Or am I missing something?

 

[razorlab]

So if the OEM mapping closes the throttle like this, how can we expect to not have this while running a JB4? In this thread people have mentioned that the throttle shouldn't go below 80% with the JB4 while the pedal is at 100%, but I was seeing 47% on map 0. Or am I missing something?

Ask the JB4 tooner bois.

 

[i3igpete]

So if the OEM mapping closes the throttle like this, how can we expect to not have this while running a JB4? In this thread people have mentioned that the throttle shouldn't go below 80% with the JB4 while the pedal is at 100%, but I was seeing 47% on map 0. Or am I missing something?

That is correct, catless downpipe will cause the DME to use thottle closure as a tuning knob on a jb4-less car. By adjusting with wastegate signal on a jb4, you are cleaning up the behavior from stock.

If you leave the EWG unadjusted, will it hurt anything? Not any worse than a dinantronix / racechip / jb-plus. All of those adjust boost sensor signal without wastegate control, and thus they will all trigger closures on catless cars. You just don't know it because none of them offer OBD logging. Side note the dinan unit will get RPM from the cam sensor, so at least you won't get "implausible pressure" errors at idle

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