Going from NA to boosted I know I am going to upsize my injectors from 42# to 120#. My question is there any advantage one over the other for hi or low impedance? This is other than the obvious current supply needed to open the injector.

 

1st thing you need to know, what does your efi system support.

 

I'm pretty sure the XFI will support either but I will check. The main thing is the open/close time. Do milli seconds really matter considering the extra amp draw and heat of the low impedance? High current and heat usually lead to early failure, at least in my industrial experience.

 

That theory doesn't apply in this application. The low importance injectors are rock solid. I have run 16 Siemens Deka 225PPH injectors on my methanol fueled SBC for over 10yrs without a single issue. The Billet Atomizer injectors (160PPH to 850PPH each) are usually only used in drag racing applications are 8A/2A as well but have proven to be hard on some system's injector drivers so much that Holley and Big Stuff 4 Pro Extreme systems now recommend using their external driver modules. FAST XFI offers a heavy duty driver upgrade for about $250. Haltech which I represent worked with Billet Atomizer closely and their Elite 2500/2500T/REM units do not seem to have any issues with them. All currently produced aftermarket EFI systems should support 8A/2A Peak/Hold injectors. OEM systems are generally limited to high impedance only. Hope this helps.

 

Impedance not importance, ......
This is not a Bar Room, this is a Engineering Forum, I have removed the curse from your post as it offered no new knowledge on the subject.
Tom Vaught

ps I have been involved with Haltech EFI systems since 1996 for racing applications.
Boats, snowmobiles, Performance vehicles, and with dyno testing. For many years they built fine products. (As have quite a few other suppliers.) But they were one of the first doing 16 injectors.
The race car in 1996 used 16 160 lb/hr methanol injectors and Twin Turbos, it was a 6 second car in 1996.
By the way that race car today is shown weekly in a TV show in the USA driven by a guy named Chief.