[darkpuppet]

(07-10-2010, 07:47 AM)ZTWsquared Wrote: That's last bit is a double edge sword because the addition of water meth really richens the mixture, and some tuners are loath to lean the gas out, they'd rather reduce the water-meth ... which in turn means a reduction in cooling-effect, which in turn means the ECU pulls timing ... and so around it goes.

Fortunately I convinced Pat to give me control over the WOT A/F and timing - and that's all I will say about that.

Do you have a wideband O2 sensor?

If so, I'd go ahead and lean out your fuel at WOT -- I would think you should be able to aim for a 12:1 ratio under water meth and be perfectly safe...

Not to mention you should be able to increase your timing as well. It would take some maths to figure out, but the octane increase of the water/meth injection would provide an almost equal (or greater) benefit than the cooling effect... and this is where a knowledgeable tuner comes in -- because they should be upping your timing as if you ARE running a higher octane under WOT.

If you're seeing a seemingly significant rich burn, it could be either too much water/meth or an incomplete burn from the increased octane...

unfortunately, I don't have any hands-on tuning experience with water meth, so I don't know what the spark tables should look like...though, I wouldn't mind seeing what you have -- could be something obvious.