I currently have 24# fuel injectors for a zz4 / tpi setup. What size should I be getting to be safe and have it run optimally?

 

If you wanna go budget a set of the FMS 42s would be a good choice. If you're going to get new I'd do the 60lb/hr Dekas or one of the new sets of high-Z injectors. I think they are up to 80s now. If you have a good box it shouldn't be much more work to tune em in.

 

I would say the the minimum 30 pounders max no bigger than 42 pounders

 

http://www.rceng.com/technical.aspx

42 would be the minimal I would consider assuming 7.5 PSI of boost on an otherwise stock ZZ3. The engine is rated at 355hp and add another 175hp or so to it and you're looking at a solid 525hp. Even going with a .50 BSFC (likely conservative) you're talking about needing 42s. 30s wouldn't cut it with out static FP increases and high duty cycles.

 

42lb ford lighting injectors

 

thanks guys! if i do 42#ers, would I need to re-tune?

 

what procharger/boost level? how much power are you trying to make? pump gas? e85?

I'm going to be pushing my zz4 to 500ish whp with 60 or 80 lb injectors for 93 pump gas, the 80's will leave me room to grown with a new short block. You dont want to run your injectors at 100% duty cycle if you can avoid it i've been told, so don't go for the minimum if you can afford to go a little bigger (but not too big!)

yes your going to need a tune

 

the 42's are on now - I don't know what boost level just yet, but it is a p600b and will be running on 93.

 

Depends on the management system, those injectors by themselves should handle 500whp fairly easily, if not, just jack up the pressure to LSx levels and make those flow more like 48's.

If using an FMU, the pressure is gonna spike ALOT to make the injectors flow alot more, depending on the ratio rise by the FMU. This will be harder on the fuel pump so be careful. 42's will be enough in this case.

60's are good sized injectors, they can handle likely 600whp. I know my friend made 700whp with them on a lsx motor but he ran alittle higher pressure so they may have flowed more like 68's.