[keithmac]

I`ve tried a fair few mixtures and quantities of water/methanol on my GTO Twin Turbo, from 500cc/min to 2000cc/min of pure methanol currently.

I have always tuned for 11.5:1 petrol AFR, regardless of the actual ratio of water/ methanol/ petrol and never had a problem with this method (not to say it`s right though). All wideband controllers derive AFR from the Lambda reading, so I`ve always tuned for the same lambda value..