N/A=Pig Rich at WOT?
Thread Starter
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Scion Evolution
Joined: Feb 2006
Posts: 3,777
From: Orlando, Fl//Scion FR-S
Well guys I was looking at how my car was working during different loads with my wideband, and saw that at WOT my car even hitted 10.6AFR and the stayed on 11.3-11.5 and went again 10.7 and I was like, Why is it so RICH when this car is not so modded. Is anyone else with a wideband recording this in N/A setups?
Yes - When I dynoed my car it was running way rich - around 10's for AFR. Try taking out your ECU fuse to reset the ECU, then after plugging it back in, idle the car for a few minutes then drive normally - you should see better AFR's
Thread Starter
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Scion Evolution
Joined: Feb 2006
Posts: 3,777
From: Orlando, Fl//Scion FR-S
That's what I did 3 days ago, sine I connected the wideband. I disconnected the battery for 30 minutes, while I was working on it and then reconnected it and saw the readings today when I got to install the gauge itself. So those are my normal AFRs.
your car ran rich? mine was running on the leaner side with cai, header, spipe, and exhaust. i was in the mid to high 13's. then at redline it would spike up to like 14 something... i had to richen it to get it back down.
Originally Posted by dstyle
your car ran rich? mine was running on the leaner side with cai, header, spipe, and exhaust. i was in the mid to high 13's. then at redline it would spike up to like 14 something... i had to richen it to get it back down.
Originally Posted by RSXaco
Originally Posted by dstyle
your car ran rich? mine was running on the leaner side with cai, header, spipe, and exhaust. i was in the mid to high 13's. then at redline it would spike up to like 14 something... i had to richen it to get it back down.
Stoich is approximately 14.7: 1 (it can actually vary depending on what is in the fuel). That is the optimum mixture to acheive a full burn and low emmissions (a result of a full burn). Running FI you will see much richer setups to keep the system safer on the engine.
A common misconception around this is that if you add more fuel because you are upping boost, you are making it "richer", which is untrue unless you change the ratio.
So, technically you arent running the car "lean" at 13:1 on a stock setup, you are running rich compared to stoich (stoichiometric ratio).
Thread Starter
Senior Member




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Scion Evolution
Joined: Feb 2006
Posts: 3,777
From: Orlando, Fl//Scion FR-S
Yep, I think that's the stock setting working there, and also because we use regular fuel the ECU pulls enough back to be REAAAALL safe. I think. A best AFR for N/A would be between 12.7-13.5 AFR. Idle 14.7 and suppooooosedly, 15.1 for cruising, since he engine is under no heavy load. But I think a safe margin at cruising would be between 13.5 and 14.5AFR. What do you think guys?
Hmm Well ive been using the search ,wanting to find answers. So i guess ill even try to brings this old thread back lol. I was wondering if i can get an update? What are you doing about this rich A/F ratio soros? My tc has been burning extreme gas with my I/H/E setup.
Lol thanks for helping me bring this thread back up, spot. But with just my weapon-r intake with ram air, tsudo midpipe, and tanabe axleback. I was gettin around 220 per tank for months. With the header ive been getting 180 per tank. For about 4 fill ups. This is with 50/50 city highway, even though that shouldnt even drop me to under 200 a tank.


