I have an 86 Iroc with a 406 tpi that I am currently setting in. I got all my stuff to do da programing,(execept the ziff socket and epproms that haven't came in yet). And I am running the 89 tdf file with the 89 arap bin.
I'm running twisted wedge heads, about a 270 roller cam, and 24lb injectors.
My question is?.....is there constant or any thing that you change to let it know the displacement of the engine. What should I change to keep it from leaning out.
Being a larger engine, I have a fear of it leaning out at WOT. Also where is it that you disable your cold start injector.
Any suggestions will be grately appreciated.

 

I can answer one... There is no cold start injecter code in the ARAP, or even the stock 89 bin. If you still have one plumbed to you intake, make sure it is unplugged from the harness.

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Mike Metzler (Desert86Roc)
Mike@SpeedworldMotorplex.com
[*] Webmaster: SpeedWorldMotorplex.com[*] Click Here For My Racing Page[*]86 IROC 305 TPI (406 build in progress)
ET's @ 1250 ft[*] 14.28 @ 95.461 mph (uncorrected, NOS, no headers)[*] 15.365 @ 86.785 mph (uncorrected, Headers, no NOS)

 

There is no displacement constant necessary with MAF cars since the MAF is measuring the actual airflow and not calculating it. You'll need to change the injector constant to 24#/hr if they're not Ford SVO injectors and about 26#/hr if they are since Ford rates their injectors at a lower pressure (which means they flow more at the pressures TPI engines typically run). If your block learns in most of the block learn cells are all lean or rich, you can adjust the injector constant to get them closer to 128.

To keep from leaning it out in the upper revs, you'll need to adjust the PE (power enrichment) vs. RPM table and possibly the PE vs. coolant temp table to make global changes to your WOT (well, PE, but it's practically the same thing) fueling.

Regarding the cold start injector, I'd unplug it and/or buy a block-off kit from Street and Performance (www.tunedport.com) and play with the Open Loop AFR %Change vs. Coolant Temp table to mimic it's function. Actually, since you started with the ARAP bin, you probably won't need to touch that table if you disable your cold start injector.

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Greg Westphal
'87 IROC 305TPI/A4

 

If your block learns in most of the block learn cells are all lean or rich, you can adjust the injector constant to get them closer to 128.

I'm new to this. What do you mean by 128?...

 

To keep from leaning it out in the upper revs, you'll need to adjust the PE (power enrichment) vs. RPM table and possibly the PE vs. coolant temp table to make global changes to your WOT (well, PE, but it's practically the same thing) fueling.

Hey Greg,
I noticed on the tables that it has %Change.
What's it referring to? To keep it from leaning out, do I need to raise the precent change or lower it. How much would be a good start.......Just need an Idea.

 

Z-BOSS,

128 is the middle of the range for block learns and integrators. For more info on them, read the article at:

http://www.racer-x.f2s.com/proc/blm_int.htm

The %Change to the PE is how much the injector pulse width is modified (usually increased) in the Power Enrichment mode to add more fuel. Raising the percentage adds more fuel, hence richens the mixture, which would keep you from leaning out. It's much better and safer to start too rich than too lean. For a good start, I'd look at the PE tables from the regular '89 350TPI bin (like the AUJM bin) at:

http://www.eecis.udel.edu/~davis/z28/

and maybe increase those values some to be on the safe side...

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Greg Westphal
'87 IROC 305TPI/A4

 

thanks alot,
I really appreciate the reply!

 

The %Change to the PE is how much the injector pulse width is modified (usually increased) in the Power Enrichment mode to add more fuel. Raising the percentage adds more fuel, hence richens the mixture, which would keep you from leaning out. It's much better and safer to start too rich than too lean. For a good start, I'd look at the PE tables from the regular '89 350TPI bin (like the AUJM bin) at:


I did the comparision as you said and I noticed that the arap bin is burning leaner at WOT.(Am I right here)
So I take it that GM programmed their cars to run a little rich at WOT, which actually hurt their performance.(would that be right)
Since my engine has more displacement(406) it would be best if I raised the percentages on the original GM bin alittle, right?.

 

The MAF uses the delta in temps across a hot wire, the MAP uses MAP and rpm. Both reguire calculations.

Also, the MAF voltage drops lag actual airflow in all transistions, so it's also always wrong. Also, with no MAP AE correction it's gussing at what AE is best.

The newer MAFs are much better, but the MAP will always read *faster*.

Either have there strong points.

 

You're right Z-BOSS, the ARAP bin is leaner at WOT, and most of the GM cars are way rich at WOT, so there's power to be made by taking out some fuel there. Of course, you don't want to go too far and lean it out or get some knock... Yes, for your 406 I'd raise the percentages quite a bit to be safe until you can get some data and see how rich/lean it is. You should work on getting your normal-cruise block learns down to the 126-128 range first, then work your way up.

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Greg Westphal
'87 IROC 305TPI/A4