AF Ratio question?

Starfire

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So I have my gauge set to turn on a warning light anytime i go under 11:1, well every time I got WOT I do, doesn't that seem too rich? I thought I should be about 11.5-11.7:1 running about 7.5lbs boost.
 

JeremyH

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Mine does this as well, at throttle tip in it goes rich 10 ish for a sec, then steadies around 12.5-13.0 and as i hold wot and boost starts to hit the a/f drops and steadies out at 11.8-11.9.
 

Starfire

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Mine will stay there though, just thinking i'm loosing power running rich and also taking a chance of clogging cats.
 

JeremyH

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I wont ever take that chance again, no cats for me.

Did it just start doing this or has it been like that?
 
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KungFuHamster

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with a power adder id rather err on the side of safe (rich) than lean. rich may clog your cats but lean will hole a piston. take your pick.
 

scramblr

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Mine will immediately dip to 10.xxx as soon as I go WOT and then climbs to 11.4-11.7 by the time I'm at the top of 4th as read on my AM Cobalt and on a dyno. I attribute it to the safe JDM email tune.
 

KDT

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Mine holds at 10.9-11.1 at WOT and I run anywhere from 6 - 9 lbs of boost depending on what pulley I have on. Yes that's pretty rich and costing some power but it is safe. I have an offroad X pipe so I don't have to worry about the cats. Here is a copy of my dyno sheet running Brenspeed's Stage 0 tune. My Stage 1 tune runs the same way, very rich. However, it still makes all the power I am willing to put on a stock motor though.
 

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Bkid

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Wow I went to a dyno day yesterday and they told me I was running way to rich.It seems I may not be. I also thought my numbers seemed way low for my times,not that I care about the numbers. Track times are what matter to me.
 

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KDT

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Wow I went to a dyno day yesterday and they told me I was running way to rich.It seems I may not be. I also thought my numbers seemed way low for my times,not that I care about the numbers. Track times are what matter to me.
I'm not sure what the ideal AFR is with nitrous but yours is bottomed out on the graph. I'm sure some of the nitrous guys will chime in. I'm curious myself. Also, I know you are making way more than 306rwhp. What's up with that dyno chart?
 
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Vapour Trails

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My gauge has always performed similarly: initially rich then finds its way to mid 11s. I don't think it's anything unusual.

As for clogging cats, the vast majority of driving is at steady cruise and 14.7.
 
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MikeVistaBlue06

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So I have my gauge set to turn on a warning light anytime i go under 11:1, well every time I got WOT I do, doesn't that seem too rich? I thought I should be about 11.5-11.7:1 running about 7.5lbs boost.


Nope, 11:1 is where you want to be when you're WOT. Mine sits at 11:1 at WOT (on the dyno). During normal driving it will run 14.7:1. Normal highway driving will also clean the gunk out of the cats.
 
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