afc and egt?

[Tamago]

Originally Posted by o89canucks

I don't see a difference on leaning out a turbo vs. na car, leaning is leaning wether you have a turbo or not.

the difference is that the DSM guy is probably leaning to 14:1. turbos make engines more efficient, volumetrically and thermally (at low boost)

stoich is 14.7:1. that's what the yaris ECU is going to try to achieve in closed loop. leaning the engine out further will simply overheat the exhaust manifold, as well as your pistons, valves, everything.

so you'll get better fuel mileage at the cost of engine longevity, which does more harm to the environment than leaving well enough alone.

[o89canucks]

Originally Posted by Tamago

the difference is that the DSM guy is probably leaning to 14:1. turbos make engines more efficient, volumetrically and thermally (at low boost)

stoich is 14.7:1. that's what the yaris ECU is going to try to achieve in closed loop. leaning the engine out further will simply overheat the exhaust manifold, as well as your pistons, valves, everything.

so you'll get better fuel mileage at the cost of engine longevity, which does more harm to the environment than leaving well enough alone.

Longetivity, yes, if you exceed safe temp ranges...which is what the egt gauge is for. Cast iron exhaust manifolds are made to withstand temperatures up to 1600F before doing major damage, I still wouldn't recommend running that hot for any extended period of time though. You still may get a decent gain by running egt temps 2-300 degrees over stock levels.