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  • 2015 - 2023 (S550) Mustang -General/Talk

Stock Afr's

  • Thread starter Thread starter SilverS550
  • Start date Start date Mar 20, 2015

SilverS550

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Mar 5, 2015
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Mar 20, 2015
#1
  • Mar 20, 2015
  • #1
What are you guys seeing for AFR's at WOT with an untuned motor? I'm seeing 11.8 -11.9 on 93 octane. That would great with boost, but that's too rich to me for a NA motor.
 

84Ttop

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#2
  • Mar 20, 2015
  • #2
The few dyno pulls we made while mine was stock showed 12.4-12.6 afr's at wot (automatic car)

I would imagine some substantial gains just leaning the car out a little in your case
 
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SilverS550

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#3
  • Mar 20, 2015
  • #3
84Ttop said:
The few dyno pulls we made while mine was stock showed 12.4-12.6 afr's at wot (automatic car)

I would imagine some substantial gains just leaning the car out a little in your case
Click to expand...

That's exactly my thoughts on it. 12.5 would be ideal. I'm okay on pump gas and no boost at 12.8.

Might need to cut a few plugs the next time I strap it down and see how they look, 'cause that's a little fat for being NA.

Next time it's on the dyno will be with the tuning though, so I'll see what it's doing with the tune on it.
 

justinakajuice

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#4
  • Mar 20, 2015
  • #4
I was just playing around with that in my gauge cluster yesterday. Mine was in the high 11's (under load), close to 12. Seems to be the same across the board.
 

SilverS550

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#5
  • Mar 20, 2015
  • #5
I thought I noticed it go really rich on the initial hit in the video when I was at the track, but didn't really think about until yesterday when I was playing around a bit. As soon as I'd mat it it went right down to 11.8 - 11.9. I thought here is no way it's going that rich, but each time it dipped right down there and never came above 12.0 while it was WOT.

Those are numbers I look for in the '88 and the Chevelle, but they're both running high teens for boost on the street.
 

Noobz347

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#6
  • Mar 20, 2015
  • #6
I don't actually know what the compression ratio is on the new motors but I would hazard to guess that it's more than 9.5ish.

Yeah, those numbers would be kind of rich for an NA Windsor but don't seem extreme at all for higher compression.

What's the AFR you guys are seeing at idle and cruise?
 

SilverS550

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Mar 20, 2015
#7
  • Mar 20, 2015
  • #7
Idle and cruise is in the 13.8 - 14.2....totally normal.

Compression on these 5.0's is 11.0 - 1.

I'm gonna cut a few plugs next time I have it strapped down and see what the fuel ring looks like.
 
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