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WOT Target AFR ?

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Old 03-07-2008, 10:32 PM
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Car: 82 Z28
Engine: 383 SP EFI/ 4150 TB
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WOT Target AFR ?

Just installed my HSR and looking to do some tuning
My datalogs are showing Target AFR at 11.85.

Is this a suitable figure?

I have read for rough NB tuning , WOT O2 readings around the 900+ mark are OK ( at least not lean )
Mine almost 900 flat WOT with no knock .
Is there a adjustable target AFR number in Tuner Pro (6E )
or do you change through Target AFR % VLV8 and temp?

11:1 383 HSR
Old 03-07-2008, 10:55 PM
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Re: WOT Target AFR ?

yes your Power enrichment PE tables are used to make target WOT air fuel ratio. Your motor shoots for a target stoichiometric air fuel of 14.7 and all the other calculations i believe are based on this. It makes percentage based fuel changes to move that 14.7 to a ratio like 12.5 or w/e you want it to be

Do you have a wideband o2 sensor? Whats the readings on that? 11.85 is somewhat on the rich side. Generally n/a will want 12.5-13.0
Old 03-08-2008, 05:33 AM
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Re: WOT Target AFR ?

Thanks ,
I am running the ARAP bin which stock is adding in 13% fuel at running temps and 7-9% in the upper LV8 regions so I assume that gives me a total of 20% more fuel OL .That ballparks to around 11.7 target AFR.
Can I change target AFR by just reducing the temp AFR target % change numbers?
Is this OL target AFR only for the time when not in CL or does it cover OL when WOT (in PE )?
You also have PE v RPM and PE vTEMP add in % fuel as well.

No WB at present , trying to get a rough tune before going out of town to dyno.
Old 03-08-2008, 01:42 PM
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Re: WOT Target AFR ?

You also have PE v RPM and PE vTEMP add in % fuel as well.
these are best for WOT fueling.

I think the OL target AFR stuff is only for open loop mode but not at WOT. PE mode covers that i do believe.

Thing with target air fuel ratio stuff is that it isnt always right. You may command a 12.5 to 1 airfuel ratio at WOT, but it could be anything. Wideband will help, but definately shoot to keep o2 sensor milivolts in the 950 range at WOT. I was around 880 or so and was 14.5 to 1 AFR, or very lean.
Old 03-08-2008, 02:06 PM
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Re: WOT Target AFR ?

Originally Posted by Orr89RocZ
these are best for WOT fueling.

I think the OL target AFR stuff is only for open loop mode but not at WOT. PE mode covers that i do believe.

Thing with target air fuel ratio stuff is that it isnt always right. You may command a 12.5 to 1 airfuel ratio at WOT, but it could be anything. Wideband will help, but definately shoot to keep o2 sensor milivolts in the 950 range at WOT. I was around 880 or so and was 14.5 to 1 AFR, or very lean.
O2 voltage is one place where its not consistant. My van is 12.5:1 @ 780 mv. The 3.4 in my S10 is 12.2:1 @ 825 mv. It really depends on the location of the O2 sensor and the heat it recieves @ WOT.
Old 03-08-2008, 05:51 PM
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Re: WOT Target AFR ?

Originally Posted by Orr89RocZ
these are best for WOT fueling.

I think the OL target AFR stuff is only for open loop mode but not at WOT. PE mode covers that i do believe.

.
I'm thinking that the ECM is seeing OL as a result of going into PE and throwing up that OL target number even though the fueling is from the PE tables.
Need WB to see the real world.

I have not changed any of the ARAP fueling yet except the injector cont for the 30lb SVO's.
But I had to pull alot of spark out with the ported TPI I ran engine in with and still had some WOT knock.
Ran the HSR yesterday with same settings and no knock anywhere so may be able to put some spark back in.
Any thoughts on HSR SA?
Old 03-08-2008, 05:59 PM
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Re: WOT Target AFR ?

it will definately like different spark tables than the long tube TPI setup, but i'm not sure what it really likes as far as either lots of spark or little spark. You'll have to play with that.

you really need a wideband to see your WOT AFR then you can play with timing once you know your not too lean
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