Grass roots Water Injection/ injectors

[Daniel Houlton]

Jason_Leone at amat.com wrote:
> 
>  <<For my turbo, I don't
> yet have an intercooler and don't know when I will.  In the meantime, I've
> planned on building a water injection system using basically a boost
> pressurized tank and a couple pumps to provide a pressure differential to
> inject water after the turbo.Instead though, it's very likely that I'll be
> getting an ERL AquaMist from a friend to try out.  This is the $500 job I think.
> Uses a high pressure
> magnetic/diaphram pump or something.  I won't be getting the controller
> they sell for it, just the basic system.>>
> 
> Uhh, before blowing all that cash on the AquaMist set-up...PLEASE read this

Yeah I should have mentioned.  I'm not *buying* the AquaMist (not with money
anyways), I'm *getting* one, basically free from a friend.  I agree they're
way too expensive for me, but hey, I can't turn it down.

> page! It's what the doctor ordered. Grass roots water injection for
> forced-induction.
> 
> http://home.ccci.org/Key_Information/MerkurPage.htm#H20

Been there.  Excellent page with temp reduction results and everything.  This
is pretty much the system I was basing mine on.  FYI for those that haven't
been there yet, he got better temp reductions with the water injection (< $100)
then he did with his custom Spearco air/water IC (~$700).


> 
> You also mentioned that your injectors were hitting the 100% duty cycle wall
> under full boost (9psi), and that you heard anything over 80% was dangerous.
> Well, it depends on a lot of variables, but running most Bosch injectors at 90%
> is fine. They can handle it all day long. 95% is pushing it. 100% is
> unacceptable. If you could tweak the injector pulse width values in the code,
> you could swap in larger injectors and simply run the duty cycle at
> significantly less at idle...and close the pulsewidth to the about the lowest
> value the ECU can go (let's say 5ms). Then have normal values up top. That would
> avoid running extremely rich at idle, but would be fine under boost. One of the
> problems with my Motronic 2.9 version, is that it can't lower the pulsewidth
> below about 4ms. When 440cc/min injectors were swapped in, it would run rich at
> idle. The code couldn't be tweaked any further. Result? Plenty of fuel under
> boost, but black smoke at idle. Kiss $35 worth of new NGK dual-electrode plugs
> goodbye. Fouled beyond cleaning. Motronic out, Electromotive in. No more MAF
> sensor troubles either. Speed Density and forced-induction is a match made in
> hot rod heaven, IF...you have the right software. =)
> 
> Jason
> '93 SLC

Yeah, that's a big if.  If I had an aftermerked EFI I could do about anything I
wanted.  Too expensive though and I'm not willing to replace the stock ECM.  In
a sports car? yeah maybe.  But not worth it to me for my truck.  Even modifying 
the stock ECM is out since there's no scanners or chip makers for it that I'm
aware of.  Not sure I'd want to fork over the cash for a one-time chip anyways.
Too little bang for the buck.  I would go to a complete system like an Electromotive
unit before I did that.


--Dan