Need some input on settings for afc, car has sri, cat-back and tb mods, tested today with a motec wideband on the street air/fuel
was 13.8 cold engine after the underhood temp went up the air/fuel was 13-high 12's doing pulls in 3rd and 4th. The sri in sucking in warm air at this point. So what I was wondering is what air/fuel ration are other people running richer or leaner. Did a search lots of topic for the evo guy but nothing for th n/a lancer.

 

I've seen numbers so varied on lancers than from car to car it's probably not a good comparison. 14.7 is total stoich though so it looks like you can add some fuel to it. What are your Hi, Low throttle %'s set at?

 

Thanks for the quick reponse, low at 10% hi at 70% cruising reading is 14.7. Its at wot that I get the other readings

 

kinda long but relevant. PMs from Boe (our resident RRM turbo guy):

[Narrowband O2 sensors] can be as much as .5 off!! Not that you can't tune with them but you need them more as dummy safeties to know if something is wrong/if you go lean! For tuning when all you have are those things you need to be more by feel as well and 4th gear is where it's at. In third or lower gear you can actually pull thru detonation without feeling it. In 4th you'll feel it and see it! For turbo on 91 octane tune for a 11.9 all around AFR and go rich about 11.5 at peak torque. For NA try to be around 12.8 all around and at peak torque be around 12.3 AFR. For 93 octane raise these points by .3 on all to maximize higher octane! Goal is to be as close to detonation point in timing and fuel but be safe enough to keep exhaust temps low!

Detonation more or less feels like a studder/shakking of engine with no gain in speed/rpm/power. If you keep it up it destroys the engine. Sometimes it is so slight you only hear it as a slight pinging noise from engine while under load(driving hard) This is why most tune on dyno as 4th gear tuning there is not a problem...

your right about richness in lower gears if tuning in 4th and it applies to 5th as well since it is more or less an overdrive gear. The key is to be as close to detonation point in fuel and timing as this is when most power is made and engine is maximized. However driving near this point makes it a dangerious area so usually you tune down a little by pulling at least a degree of timing out and then adding some fuel at least .3 points. It's a very touchy situation when your trying to maximize power/speed especially if your turbo/supercharged as a tank of bad gas or a unusually hot day could have adverse effects on your tune! This is also why dyno tuning is so effective as you can see things happening that you won't necessarily feel. Graph and charts show it though. As for detonation retarding engine it does if ecu is programmed that way as in the case of the evo. In the lancer it isn't. The knock sensor is set up to flash the CEL light when it senses detonation but it has no effect on timing as NA cars with low hp should never reach this point. The factory tunes them to safe. With the evo it is tuned safe but climate/weather/temps/altitudes have affects on turbo'd cars thus they need to have a fail safe/protecting device. That's the knock sensor. It will retard a degree for every knock a second sensed. If more than one in a second it retards accordingly. Our engines were not designed for turbo by mitsu so the technology/programming for the knock sensor was not included in the ECU. Oh well... nothing we can't work around though. Hope this clears up some things.

i'd go with it. follows most of what i've read. and this is for HI tuning.