AFR help with AP

jodacoto

Member
:
MS3 07
ok, i need help . i just bought an ap and istalled it with Stage1+MSCAI2 93 Octane 1.03 map , i only have mscai2, forge bpv(removed) and only use shell 93. car has incredible power after the reflash "tune", but im scared to blow up the engine cause i don't know what to look for, specifically A/F ratios #'s , like what numbers should i be getting /reading? how do i know if im runnig rich or lean? i think my af are way off in the 14-15's and when i let off d gas it displays 14.5/29.3 ( in the AP menu wich AFR should i monitor, actual afr or the other one? ) (hand)

boost seems fine never higher than 18.5 psi , k/R usually 0.0. sorry for all the questions but as you can see im lost,i thougt this would be download intall and go (smash) i went to stock bpv just in case and removed injen prefilter.
 
Stoich is 14.7. You should see your Stoich as 14.7 ish when at idle (it can and does move around a bit 14.5-15.0 at times). When WOT it should go down and with your mods you should be in the high 9's low 10's. Between shifts your afr's will go up to 29.3ish and that is perfectly normal.

What you are seeing is fine. It is showing you that the lowest recorded is 14.5 and the highest is 29.3 which are what you should expect during normal driving.

When you do a wot run you should see the low number in the 9's or 10's but don't be shocked if you see 8's. What you DON'T want to see is 13+ when WOT.

EDIT: I missed the Cobb AP in your post. You should see nothing lower than 11's with the AP when WOT. Stock cars drop into the 9's typically and I have even seen 8's before on the dyno, but with the AP you should not see lower than 11's.
 
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You don't really want to see 9's either.. that means your running pretty rich. Ideally you want to keep it between 14.7 and 10-12.
He's right about not wanting to see 13's or up WOT. That would mean your running really lean and bad things can happen.
It sounds like your fine. I wouldn't worry at all about blowing your engine with the mods you have
 
Thanks Bravnik and Speed3driver, so i think i'm fine maybe i can still use the forge bpv with this map. anyone using the injen prefilter w/mscai and cobb ap ?
 
Stoich is 14.7. You should see your Stoich as 14.7 ish when at idle (it can and does move around a bit 14.5-15.0 at times). When WOT it should go down and with your mods you should be in the high 9's low 10's. Between shifts your afr's will go up to 29.3ish and that is perfectly normal.

What you are seeing is fine. It is showing you that the lowest recorded is 14.5 and the highest is 29.3 which are what you should expect during normal driving.

When you do a wot run you should see the low number in the 9's or 10's but don't be shocked if you see 8's. What you DON'T want to see is 13+ when WOT.

EDIT: I missed the Cobb AP in your post. You should see nothing lower than 11's with the AP when WOT. Stock cars drop into the 9's typically and I have even seen 8's before on the dyno, but with the AP you should not see lower than 11's.

Actually, the AFR is never 29.3

That is the simply the (full scale) reading that you get when the injectors aren't firing ((255/128) * 14.7 = ~29.3)
 
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Actually, the AFR is never 29.3

That is the simply the (full scale) reading that you get when the injectors aren't firing ((255/128) * 14.7 = ~29.3)

Thanks but knew that. Just didn't want the guy to worry as he seemed to be doing. It's normal to see that AFR was my point not that your AFR will literally be 29.
 
EDIT: I missed the Cobb AP in your post. You should see nothing lower than 11's with the AP when WOT. Stock cars drop into the 9's typically and I have even seen 8's before on the dyno, but with the AP you should not see lower than 11's.

Last night i did a couple of WOT runs to check on AFR numbers, and got a 9.4/29.3 , this morning 9.7/29.3 does this mean the car is running dangerously rich? if so, how can i fix this?
 
Not sure you can be "dangerously" rich in the 9's. You would not be getting full potential power, but I don't really see how this could be harmful. Getting up into the 10's or 11's at WOT should produce more power, as others have observed. 9's at WOT aren't gonna be dangerous.
 
Nah - You're fine man. Too rich is not a horrible thing, I have seen totally stock hit 8.'s. Car companies play it safe and most cars run richer than they need to as a safety precaution. Mazda is just REALLY safe. Cobb also played it safe with the OTS Maps as you can see.
 

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