Scotthatch wrote: ↑Wed Jun 20, 2018 11:06 amjoe 90 wrote: ↑Tue Jun 19, 2018 7:37 am If you're using EFI, in particular the speed density variant of EFI, it's really not compatible with water injection due to the way it works (Cooling the charge in the manifold increases the density, but the computer has no way of knowing how much by) . It's going to lean out the AFR when it turns on. Adding methanol or ethanol to the mix will tend to richen it back up.
That's yet another big disadvantage of speed density systems and a big plus for MAF based EFI.
If you're starting with a MAF based EFI system and the AFR is correct then adding water and methanol will make it richer, same with a carburettor.
This is a very interesting take on what happens and worth remembering when doing this
Not only that but if you're using a WB o2 sensor, it won't read correctly either, even using WI on a MAF based system.
WI always makes them read incorrectly.
It changes the partial pressures of all the gasses involved.