SUPRA ULTIMATE B58 JB4 GUIDE AND LOG REVIEW (V1)

[GRMan]

No it's more like 11-16 depending on conditions.

Right…I didn’t know it’s running on such low boost, just ~1.1 bar tops

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[Phantomx]

I think @ColonelAdama i’m going to readjust the duty bias back down to your settings. Getting some other passes and time I can see the overboost your talking about. What I’m realizing is playing with higher boost anyway, the fuel trims kinda ramp up to the 40’s pretty quick but then settle right down in the heart of the run. Cars running strong, even 4th today was tripping the traction control light briefly. I also see that bit of timing pull too, playing with it getting it dialed in.

 

[ColonelAdama]

I think @ColonelAdama i’m going to readjust the duty bias back down to your settings. Getting some other passes and time I can see the overboost your talking about. What I’m realizing is playing with higher boost anyway, the fuel trims kinda ramp up to the 40’s pretty quick but then settle right down in the heart of the run. Cars running strong, even 4th today was tripping the traction control light briefly. I also see that bit of timing pull too, playing with it getting it dialed in.

Pretty normal for trims to spike up a bit before dropping with JB4. 40s is OK if you log occasionally. If you start seeing it get near 50, it's too much ethanol or boost.

Glad your car is running well. Really looking forward to next dyno run! Wanna see that 500 whp

 

[ColonelAdama]

Right…I didn’t know it’s running on such low boost, just ~1.1 bar tops

That's 11:1 B58 compression for ya. Unusually high for a boosted car. That's why these cars require ethanol/methanol to push anything over 20 psi.

My GTI (9.6:1) will happily push 25 psi on 93 due to low compression.

Even S58 (9.3:1) can do 25-27 psi on 93 since its lower compression than B58

 

[razorlab]

That's 11:1 B58 compression for ya. Unusually high for a boosted car. That's why these cars require ethanol/methanol to push anything over 20 psi.

21+ is actually 10.2 CR
20 is 11.1 CR

21+ has higher torque-target programming because of the lower compression (stock)

 

[ColonelAdama]

21+ is actually 10.2 CR
20 is 11.1 CR

21+ has higher torque-target programming because of the lower compression (stock)

Interesting, didn't realize they changed pistons/crank/heads(?) between 2020-2021. Thought it was just the manifold.

 

[razorlab]

21+ is actually 10.2 CR
20 is 11.1 CR

21+ has higher torque-target programming because of the lower compression (stock)

Some ECU table differences between 20 and 21+ for reference:

 

[razorlab]

Interesting, didn't realize they changed pistons/crank/heads(?) between 2020-2021. Thought it was just the manifold.

Yes, head is different, 20 has the exhaust manifold integrated into the head. 21+ has six seperate ports like older style head castings and therefore the six log exhaust manifold.

 

[zrk]

20 has the intake manifold integrated into the head

?

 

[razorlab]

?

You know what I meant, the exhaust runners are cast into the head and merge into two ports where the 21+ has six "normal" exhaust ports.

Literally states it in the tech doc that the manifold is cast into the head on 20.

 

[Jesse DaBears]

You know what I meant, the exhaust runners are cast into the head and merge into two ports where the 21+ has six "normal" exhaust ports.

Literally states it in the tech doc that the manifold is cast into the head on 20.

Zacks just a chooch. We know what you mean.

 

[zrk]

Zacks just a chooch. We know what you mean.

I'm just a chooch. We knew what you meant.

 

[Phantomx]

I had to freakin lookup what Chooch was… never heard that LOL

 

[Phantomx]

Ran a quick log with e40 (probably more like e37) but up’ed the E content a bit and I dropped the boost a tick at 4500 trims were taking awhile to adjust back down so just pulled 1psi out there and stopped maxing out and seems to recover a little quicker.

I did forget to put it in sport mode so the shifts were lazy but good run.

https://datazap.me/u/phantomx2k/mhd-bef-jb4-e40?log=0&data=1-3-4-12-14-18-19-34&hg=19-1-4-3-18-14-12

Here was an earlier run but I bumped the rev limiter apparently I have to shift a bit earlier to catch it. Speaking of what do you guys shift at?

https://datazap.me/u/phantomx2k/mhd-bef-jb4-e40?log=1&data=1-4

overall feels strong it’s just a different animal now. I don’t like that trim spike but as mentioned seems normal and it adjusts down pretty quick (within 1k rpm) timing seems steady around 15 and AFR looks good in the 12’s.

Thank you guys for all your help it’s also been a great learning experience.

 

[ColonelAdama]

Ran a quick log with e40 (probably more like e37) but up’ed the E content a bit and I dropped the boost a tick at 4500 trims were taking awhile to adjust back down so just pulled 1psi out there and stopped maxing out and seems to recover a little quicker.

I did forget to put it in sport mode so the shifts were lazy but good run.

https://datazap.me/u/phantomx2k/mhd-bef-jb4-e40?log=0&data=1-3-4-12-14-18-19-34&hg=19-1-4-3-18-14-12

Here was an earlier run but I bumped the rev limiter apparently I have to shift a bit earlier to catch it. Speaking of what do you guys shift at?

https://datazap.me/u/phantomx2k/mhd-bef-jb4-e40?log=1&data=1-4

overall feels strong it’s just a different animal now. I don’t like that trim spike but as mentioned seems normal and it adjusts down pretty quick (within 1k rpm) timing seems steady around 15 and AFR looks good in the 12’s.

Thank you guys for all your help it’s also been a great learning experience.

Just checked one since I'm not at my PC but I see that it pulled boost due to high trims, so E has to go down some with those boost levels. Alternatively, see if Terry can up the fueling in the BEF.

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