2 bar tuning
08-09-2006, 06:52 AM
#11
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The stock MAF on our trucks are good for about 60 lb/min or around 12000HZ. When running FI it does not take great deal of effort to max this out. I have seen boosted 6.0L's max this at 2-3 psi of boost. I run 12 psi non-intercooled on my 5.3L and am seeing reading max at 64.5 lb/min at 5800 rpm's. I added a 2 BAR MAP in tandem to my stock MAP in preperation to go to a 2 bar SD tune. I currently log 184 kPA at 5800 which agrees with my Dakota Digital Boost gauge reading of 12 psi... atmosphere is 103 kpa and 1 psi of boost is equal to about 6.8 kPA. Since the stock OS maxes out at 103 kPA for a N/A vehicle, you rely on the MAF for boosted fueling. When you run out of MAF...you go 2 BAR...... There is a new Granatelli 100mm MAF out, but it has the same 60 lb/min 12000 hz limitations of the stock MAF...this is due to the OS in the PCM.
With a 2 BAR SD tune, the OS is modified so your VE table increases from a 15 kPA - 105 kPA table to a scale of 5 kPA - 210 kPA. This allows you to toss the MAF and use the VE table on both sides of atmosphere (103 kPA). You can now tune fueling in both vacuum and throughout the boost range up to 210 kPA which works out to be about 15.7 psi of boost.... for those hard core users, the 3 BAR SD OS is available for some models..... HP Tuners is what I tune with and the 2 BAR SD OS for my truck is $99.00.
BTW: GM P/N: 12580698 AC Delco: 213-1631 is a good number. That is what I have installed on the AV and jacked into HP Tuners..... Pictures, write up, and JPEGS of HPTuners Log showing kPA readings are here:
http://www.chevyavalanchefanclub.com...c,67297.0.html
Hope this helps.....
With a 2 BAR SD tune, the OS is modified so your VE table increases from a 15 kPA - 105 kPA table to a scale of 5 kPA - 210 kPA. This allows you to toss the MAF and use the VE table on both sides of atmosphere (103 kPA). You can now tune fueling in both vacuum and throughout the boost range up to 210 kPA which works out to be about 15.7 psi of boost.... for those hard core users, the 3 BAR SD OS is available for some models..... HP Tuners is what I tune with and the 2 BAR SD OS for my truck is $99.00.
BTW: GM P/N: 12580698 AC Delco: 213-1631 is a good number. That is what I have installed on the AV and jacked into HP Tuners..... Pictures, write up, and JPEGS of HPTuners Log showing kPA readings are here:
http://www.chevyavalanchefanclub.com...c,67297.0.html
Hope this helps.....
Last edited by FlaBouy; 08-09-2006 at 06:57 AM.
08-09-2006, 10:41 AM
#18
Originally Posted by trever1t
Just a small (may be way off track) question for you about 2bar tuning. If it deletes the MAF from calculating A/F then what or how does the PCM compensate for IAT's and Altitude changes?
This has helped me alot with summer heat by setting it to 1 and rescaling the VE trims dont swing as large as they did before even if the IAT gets 120+ and heat soaked
Ultimately thought whe need an adder table for the VE that is based off temp, Ive heard they are working on one.
08-09-2006, 11:03 AM
#19
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Originally Posted by 02sierraz71_5.3
If you have an 02 or later you can set the intake air charge model bias table to a value of 2 and that will solely go on ECT for calculations at 0 and it is solely using IAT, 1 is a 50/50 mix. That model has alot to do with trimming and afr concerning temp.
This has helped me alot with summer heat by setting it to 1 and rescaling the VE trims dont swing as large as they did before even if the IAT gets 120+ and heat soaked
Ultimately thought whe need an adder table for the VE that is based off temp, Ive heard they are working on one.
This has helped me alot with summer heat by setting it to 1 and rescaling the VE trims dont swing as large as they did before even if the IAT gets 120+ and heat soaked
Ultimately thought whe need an adder table for the VE that is based off temp, Ive heard they are working on one.
08-09-2006, 11:13 AM
#20
Originally Posted by 02sierraz71_5.3
Ultimately thought whe need an adder table for the VE that is based off temp, Ive heard they are working on one.
Originally Posted by Wilde
^^^This is a good tip ^^^, and has helped me with temp changes, I also use only STFT.
I thought the basis of this was more IAT temps more fuel. Which isn't always necessary. Mine is pulling tons of fuel with no "bias" at all. Hmmm.
Obviously going stft is the fix for anything under 110kpa, the pcm will fix it as per what it needs, but that confuses me as well, cause it isn't doing as the "theory" states with this bias.