2009 Jeep JK Frankenstein 3.8

I have a 2009 Jeep Rubicon JK Frankenstein 3.8 or 3.9, 4.0 who know's now.
Anywhoooo I bought a 3.8 rebuild kit from 505 Performance.
60 over 10:1 custom pistons, mild custom cam, roller rockers, header's and worked over heads.
Now I need to learn to tune this tiny monstrosity. Yeah shoulda got a v-8 but
it wasn't in the budget.
I have adjusted my axle and tire ratio as well as fan speeds "I'm in Texas and its summer so I lower all on temps by 20%"
That's about it for my current knowledge. I need to adjust for the cam, cold air intake, header's and 10:1 I believe.
I have attached a log file from my drive to work this morning. Please if you require anything different or me to
setup my scan different just let me know.
Thanks in advance for any help with this little money pit.
TC.

Nice, I like the little 3.8L. I started this thread last winter and am working on some additional changes for hot summer temperatures and different altitudes -- Mostly the new changes are a bit less spark advance and richer PE to keep exhaust/cat temps lower and minimize getting into over-temperature enrichment. I'll be updating that thread soon, am pretty much done.

Suggest copying the Fuel Temperature - Fuel Mass Multiplier table. This change keeps the fuel trims closer to zero with hot underhood temperatures. And bypassing the PE (power enrich) delay with Fuel>PowerEnrich>Delay>VSS Min set to 127 mph works well.

To set the VE: Log the STFT and LTFT, drive in closed loop (not full throttle PE), and adjust the VE table until the trims stay close to zero throughout the RPM and MAP range.

Can't view logs now, will look at them later.

:cheers:

Took a quick look at your log. -6 KR is the maximum it will go per the Max KR table and you hit the max! PE mode wasn't entered because of the delay. I'll bet you heard the detonation, which happens even on stock new engines in hot temps.

Compared with stock, on mine the spark is reduced by 3-4 deg at the higher MAP's in both the PT and PE tables, PE delay is bypassed, and PE is richer throughout. I'm tuning for 87 octane, but with 10:1 pistons 91 octane sounds better.

:cheers:

Question on the roller rockers, what (if anything) actually had to be done to the inside of the valve covers for clearance? Thinking about these, but didn't want to loose the baffle that separates oil mist for the PCV and breather.

On a side note, noticed in your log that STFT's are ~5% at the high end, indicating it's breathing better than stock and the VE needs bumping up in those spots.

:cheers:

The roller rocker are from 505 performance and yes you do have to remove the baffles but the rockers squirt like a small block so I wasn't worried about it.
I need to research all the points you gave me as I am totally new to this. It would be great if I could compare your tune to what I have done.
My email is [email protected] and I appreciate any help I can get on this issue.

Quote:

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Originally Posted by Tconners

The roller rocker are from 505 performance and yes you do have to remove the baffles but the rockers squirt like a small block so I wasn't worried about it.
I need to research all the points you gave me as I am totally new to this. It would be great if I could compare your tune to what I have done.
My email is [email protected] and I appreciate any help I can get on this issue.

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Thanks for that info. You can download my tune from this thread https://forum.hptuners.com/showthrea...th-description, it's also in the repository. The compare feature in the editor is very handy! Still fine tuning the next revision, will PM/post when it's finished.

:cheers:

Awesome, thanks!

Any new progress?
I'm currently trying to figure out how to flash your tune from the repository easily onto my JK.
Just no quality time to spend on it currently. ;-(

Quote:

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Originally Posted by Tconners

Any new progress?
I'm currently trying to figure out how to flash your tune from the repository easily onto my JK.
Just no quality time to spend on it currently. ;-(

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Yep, been tuning at different altitudes and temperatures. I'll post up a new tune to the repository in a few days, and post a note here too.

Regarding how to flash/use this tune: Upload your original tune from the PCM and save the file, load mine as a compare file (the differences will be color coded), make the desired changes to your original file based on the compare file, then save the changes as a new file and upload to the PCM.

:cheers:

Thanks man! going to play with it this week.

Hi TC, latest tune is in the first post in this thread: https://forum.hptuners.com/showthrea...440#post512440

Best of luck, hope it saves you some time :cheers: