Fuel Injector sizing

HorchataKing

New Member
May 5, 2011
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Monterey, CA
I've searched high and low, and found many very helpful answers, but I still find myself trippin' over my choice here. All of my math, formulas, and everything point to NO, but something in my head keeps telling me I can make my 550rwhp with a smaller set and get at least a little better gas mileage. I'm not looking for anything resembling great gas mileage, I'm just trying to maintain better economy than an old chevy 350 v8. So the question I pose to you all, 1000cc to much? Should I just tune them down to 750s with my FPR, or flat out get a set of something more like 680s or 750s and work from there.

ps. I do have my safc, and wideband hooked up for once I get this motor into the car and running.
 

toyotanos

What will we break today?
Staff member
Super Moderator
Nov 29, 2008
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Coon Rapids, MN
First question I have for you would be what fuel are you using? Pump/race gas needs less injector than an alcohol fuel (E-85), but you also need to realize that knock will limit power output with the pump gas more than injector sizing does.

Additionally, fuel injector size does not determine fuel economy; the tune determines that, along with driving style/habits. Running too big of an injector can lead to issues where getting the tune right can be impossible, leading to poor economy by default.

I think 1000's woud be too much for an SAFC to control accurately, you would want a standalone wired for sequential injection for best results with them.


I personally run E-85 through a set of FIC 1350 injectors with dual pumps to support them, and I should never run out of fuel (with my 67mm 7M, that is) I also have an AEM which allows sequential injection and full tuning ability so I can have power and economy too :)
 

HorchataKing

New Member
May 5, 2011
33
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0
Monterey, CA
Would be 91for DD, and have a second fuel cell mounted with 103 for walking mustangs that like to sound beefy.

I have also seen that thread, and based almost all of my math off it, with a few mods to the formulas to make up for what I'm aiming at. I've calculated between 950 and 1050cc. To me, that just seems really like high flow, considering I've heard of people making upwards of 450rwhp with 550s.

I guess the question is do people here think running my FPR at a 23psi static to flow like 750s would be sufficient, or should I buy a set of smaller injectors until I'm ready to pass the 600ish rwhp mark?