With the aem wideband failsafe set to turn off the boost controller at anything leaner than 12.0 under wot. Is there a need to have any other failsafe nowadays? Almost seems like there is no benefit but adding complexity to have much else for meth injection.

 

If you are running 100% meth. But if you are running M50/W50 or 100% water, you will loose 30-70% of the in-cylinder cooling. To be abolutely certain, you also need a EGT gauge with failsafe.

 

Are you saying that since 50/50 and 100-0 water-meth won't change AFR as much, or at all, but offer up to 70% of the cooling power of the injection, and therefore an AFR failsafe will not help?

 

100% water will not alter the AFR but will slow down the burnt rate. AFR based failsafe will not work effectively. For this type of application, egt or turbine flow sensor is recommended.

Generally, 100% water requires lean AFR running to get the best results