[Neutrino]

Originally Posted by SaabJohan

Maximum power is at a rich mixture, around lambda .92. When making the mixture much richer than that the power will decrease. Using a leaner mixture will also decrease power but also decrease fuel consumption. The lowest fuel consumption can be found some above lambda 1.

You are correct but what i was refering to is that a lot of manufacturers seem to tune very conservativelly with very rich AF ratios especially at WOT or high rpm. Cars like the EVO even go below 10.0 AF (.68 lambda) above 5000 RPM. I presume manufacturers do this to have a good safety margin against detonation.

In those cases remapping of the ECU with leaner numbers will increase the power quite a bit. And this seems to apply to a lot of cars, and this is what i was refering to. I did not mean go above 14.70 stoich (1.0 lambda) into the lean territory.

I just meant go above very rich ratios and closer (not above) to the 13.57 (.92 lambda). This should make more power and give better MPG.