Considering w/m injection for my supercharged z4m

[fr8tdog]

I'm getting my car back from ESS next week, which is a Z4M supercharged to 500bhp. The kit uses a Vortech V3 centrifugal blower and a front mount air/air intercooler. ESS won't tune for water/meth, but I would like to add it for safety and maybe even up my boost. I also have a nitrous system that I installed prior to going forced induction. My tune is an ECU reflash and it being from ESS is considered top of the line. That being the case, I don't know if it would be possible or even smart to have another shop try to tune over the ESS tune. My current pulley allows 8 psi. Is it possible to add the water/meth kit and not tune the car....and then change the pulley out for 10 psi. Am I understanding this correctly, that by increasing boost 2 more psi that it would effectively lean my current tune to allow for Auquamist w/m without going to rich? Can I then take the approach of fine tuning with different jetting and water/meth ratio? I don't have a dyno graph yet to even know what my current afr's are, but I would guess they float around 12-12.5. What results would I expect if I just added the water/meth system without increasing boost and no tune?? Thanks in advance for any info

[Howerton Engineering]

Depending on the mix and jetting you use, AFR's will typically drop .5 to 1.0. Whether this still makes power or pulls timing excessively depends on the programming of the ECU. Some cars will tolerate down to 10.5 with too much issue, some don't like to be below the high 12's.

I think tuning it with the kit/jetting maybe possible, but in the long run setting the jetting right for the application then having the car re-tuned will give the best package.

[fr8tdog]

if i increase boost with different pulley wont that lean the mixture? so then water/meth will bring afrs back in line.

[Howerton Engineering]

Theoretically yes, but you can never be sure until it works right. The dynamics of all the variables involved can sometimes make it more complicated than it seems. There is a good chance that it will work, but I wouldn't want to make any false promises.

[fr8tdog]

Fair enough, and thanks for the honesty. Sounds like I need to call ESS and pick their brains a little. Cheers
Joe