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im getting conflicting answers on this site about afr . so what is the best afr at idle and then when full throttle? would like to here from someone that tunes these vehicles , or from someone that has experience and tuned there own car. then i know what to shoot for . thank you . im boosted also.

 
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14.7:1 is ideal for NA, for boost more like 11 or 12:1.

 
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yeah at idle 14ish is where to be so you dont run pig rich.. some people feel more comfortable with mid 12 and others like mid 11. You want more power or better reliability. The leaner you go obviously the more dangerous. If it was me I'd settle at 12.0 at the most.

 
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For Boosted:
idel = 14.7:1
Cruise = 14.7:1
Load = Varries
WOT= anywhere from 11:1 VERRY conservative tune, to as high as possible without knock. Higher the ratio the more likely to have a serious problem but also makes the most HP. Its a verry fine line to walk. Most people /tunners will shoot for 11.5-12.5:1 @ WOT

 
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under boost you dont want more than 12.5:1 afr. 14.7 is stoich and thats the target afr under vacuum and 0 manifold pressure.

 
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What everyone has said is right but just so you don't get too nervous if you don't pinpoint on that ratio since you don't have fuel management that can auto tune. At idle you wanna stay anywhere from 14.7-15.2. Partial throttle 14.1-14.7 and WOT 11.5-12.5. I think anywhere in between there is safe so get your wideband and go to town. Watch for lean spikes thats my advice.

 
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If you want reliability then it would be best to stay under 11.5 at WOT. If you watch some dyno vids online you ll see some boosted vics at like 13.9 WOT, but they are going for maximum power. Off boost around 14.7. This is coming from a very relaible shop, this is their site http://speedworkz.com/

 
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Partial throttle is the hardest to tune on our cars with a piggy back. You have to walk a VERY thin line by watching the long term fuel trim. I actually need to still do some minor tuning on 2000-3000 rpm @ very low throttle position(crusie on the freeway) If your off just the smallest amount when you come down off the freeway as an example you will either be way rich or way lean

 
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Usually those AFR are from tail pipe sniffers, and they tend to measure leaner than it actually is

 
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I hear ya tfnaaf. When I let off the gas during partial throttle it runs way rich and actually hesitates a bit, so I still have more playing to do. Funny thing is when I had the cat converter on I had the car running mint and lil issues. Now with a test pipe I can't seem to get it to run like I did but I love a challenge. EMS or PCS coming soon

 
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yeah, ive just been to lazy to get the laptop out and play with it

 
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If your tuning for accuracy why would you use tail pipe sniffers, I thought it was best to measure the AFR as quick as possible?

 
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AFR at idle can be as lean as possible. The engine has no load, so whatever fuel mixture making it running, is good enough.
Turbo full throttle you'll want to be safe from knoking.
D17 need to be richer then K20.
Eg., d17 is fine with 12:1, k20 can be fine at 13:1.
Best AFR depends on the engine design.
For easier understading picture this: if you'll keep both engines at the same RPM (5000 lets say) for 1 minute. During this time d17 piston will cover greater distance than k20 piston. This means d17 piston will need to produce more energy and heat to keep it going, therefore extra richness in the fuel will keep things coller and keep pinging distance away.
k20 not need to be as rich, because it doesnt need that bit of fuel for keepng things coller inside the combustion chamber.

 
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WELL, THANK YOU GUYS FOR TEACHING ME THE INS AND OUTS OF THE AFR.
I HAVE TO TEAR DOWN MY HEAD ASSY. I HAVE OIL LEAKING IN THE EXHAUST MANIFOLD. I FOUND THIS PROBLEM WHEN I BLEW OFF ANOTHER PIPE. FOUND THE PIPE WITH OIL ON IT . GUDE PERFORMANCE F@&KED UP MY **** . SO I HAVE TO SEND IT IT TO A LOCAL MACHINE SHOP TO CK IT OVER. MIN. REPLACE VALVE SEALS. SEEMS THIS PROBLEM HAS BEEN THERE ALL ALONG BUT DID NOT NOTICE IT TILL KNOW. SO I LEARNED I NEED TO BE AT 11.0-11.5 WOT AND AT IDLE 14.7 OR SO. THANKS FOR EVERYONE THAT RESPONDED .

 
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Have you ever dealt with those guys?? Their shop is only 5 min from me. I have talked to the owner a few years back. I know they do alot of auto-x.

 
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Ive been goin there for 2 years nd recently got my integra tuned there last month. The mustang, all wheel drive, dyno that they have is the first of its kind in the country. It does the basics like horsepower runs, 1/4 mile times, but it also runs fully loaded power tests, log multiple vehicle data channels, test partial or full throttle positions, road simulations, RPM step tests and a lot of other ****. Call em up and ask for Ian, he does the tuning and the more complicated jobs.