A/F Question

jp2134

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Where do you want the coyote running?
I was recently on the dyno, my A/F sat at 12 for the whole run. Then I gradually leaned her up to run at a perfectly flat 13.
After that, she made 430/355. Mods= Tune, CAI, Boss Mani, Cat deletes.

At an A/F at 12, she made 419.

Any suggestions/comments would be a great help.
 

Voltwings

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Just remember that leaner makes more power because it is hotter. id keep an eye on that number 8 running it that lean, unless you had some serious cooling mods invested, i dont feel the extra couple horsepower would be worth it though.
 

jp2134

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I adjusted it on my handheld while I was on the Dyno. It's a friends dyno, so I just did a bunch of runs. It lays almost completely flat on 13 now.
I guess what I'm getting at, is 13 too high? It made the extra power, it was actually 416 at a 12 A/F
 

jp2134

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OK, sweet. Thanks. I know some other cars are fine at 13, wasn't too sure about this one. My T/A used to be at 12.8-13 and it was totally fine
 

scott_0

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I wouldn't go leaner than 12.5, or you'll making your own #8 thread.......
 

Shaun@AED

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Dyno readings are not accurate enough IMO. They are not programmed the same as the Factory ECU.

Dyno widebands 1.0 Lambda = 14.64:1
Factory Ford Programming 1.0 Lambda = 14.08:1

This means a dyno will always read leaner than the Ford ECU. Couple that with cats and taking measurements at the tail pipe and you could be WAY off on your dyno readings. Especially if the dyno unit is not an ECM wideband.

I tune on Lambda. .83 to .84 lambda commanded on NA Coyotes and into the .7's for boost.
 

INEEDA_TERMI

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Not to hijack the post or anything but how accurate are the factory A/F gauges?

Lol accurate enough to allow the engine to operate without Grenading. The factory wide bands are the life line of these motors. All calibrations take afr into account. Think about it man, quite sure they're pretty damn accurate.
 

Shaun@AED

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Not to hijack the post or anything but how accurate are the factory A/F gauges?

Assuming they are heated correctly and calibrated, Very accurate.
Ford uses NTK sensors on the Coyotes. I buy the same sensor with a different connector for $399 each for dyno tuning use. The ECU uses data from the Rear O2's to keep the fronts in calibration. Similar to you doing a 'free air' calibration on an aftermarket unit.
 

jp2134

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I run nothing but 93, from the same station every time. I'm kinda anal about fuel.
It was getting A/F from the tail pipe.
I have a Diablo Trinity, and it has an A/F readout, which was pretty close to what the tailpipe readings were. It was about .2 under.

But I brought it down to 12.5 to be safe.

And my commanded Lambda is at .85 at WOT
 
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mhyjek

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I run nothing but 93, from the same station every time. I'm kinda anal about fuel.
It was getting A/F from the tail pipe.
I have a Diablo Trinity, and it has an A/F readout, which was pretty close to what the tailpipe readings were. It was about .2 under.

But I brought it down to 12.5 to be safe.

And my commanded Lambda is at .85 at WOT
I'm not sure if Diablo base tune takes this in account, but I know when you get an AED or Lund or most other tuning places they change fueling on #8 to run more fuel so it runs cooler. So at your commanded lambda you are on the edge if it doesn't run more fuel to 8. Also if your gas is a little off could be trouble, most likely not during the winter months do to extra corn in winter blended gas. If you have the pro version tuning software and can do it great, if not get an AED datalog tune would be my advice...
 

Shaun@AED

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I run nothing but 93, from the same station every time. I'm kinda anal about fuel.
It was getting A/F from the tail pipe.
I have a Diablo Trinity, and it has an A/F readout, which was pretty close to what the tailpipe readings were. It was about .2 under.

But I brought it down to 12.5 to be safe.

And my commanded Lambda is at .85 at WOT

For Reference Ford Racing Procals command .86 lambda at WOT.

.85 Lambda commanded @ 14.64 = 12.44:1 air fuel
.85 Lambda commanded @ 14.08 = 11.97 (Track pack car would read this on the dash)

Same actual air to fuel ratio (lambda), different programming. This is why we use lambda.

I'm not sure if Diablo base tune takes this in account, but I know when you get an AED or Lund or most other tuning places they change fueling on #8 to run more fuel so it runs cooler. So at your commanded lambda you are on the edge if it doesn't run more fuel to 8. Also if your gas is a little off could be trouble, most likely not during the winter months do to extra corn in winter blended gas. If you have the pro version tuning software and can do it great, if not get an AED datalog tune would be my advice...

Some do run more fuel on the #8, but I do not. We solved the lean condition differently, at the source.
 

JohnRichard

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using live link, what pid do I use to check the afr...

All we have here is e10 so i found the Stoich is 14.08 is that correct?
 
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