I want to have all the fuel I would need for around 450-500 whp, will I need 2 255's or is one enogh. there are only 2 injectorson a 13-b one a 550 and the other an 850 correct? what are the biggest injectors the stock fuel rail can fit? and what type of injectors are they low impedence or high impedence, side feed or top feed, mitsu? denso? ect...........



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also are they peak and hold , saturated , ball and seat? sorry for reposting about injerctors but rx7 chick dident ask or get told much!

first of all, be aware that any change in your injector sizing will require you to change your ECU.



with that said, fds use 4 side feed injectors, 2x 550cc primaries and 2x 850 secondaries.



you could get away with 1 walbro 255 for a 500hp car..... supposedly boostn7(has a 500+ fd) only has 1 walbro in his tank. you can go as high as 1300cc inj on your secondary rail, and modify your primary rail to fit your 850cc secondaries. or if you want you can get aftermarket rails and use up to 1680cc for all 4 positions.

thanx alot, no worrys for ecu been running aem ems 4 about a year now! tunning it will be a different story

what do u mean by modify? mill? which side rail is the primary?

They bore out the injectors to flow higher.. Problem is that some people had issues with 1300cc side fed injectors.. Might be that 1300 might be slightly too big.. One thing people suggest is that if you do get them bored out, use it right away instead of letting it sit for long duration of time... 1200cc seems to be ok though.



Also, if you upgrade your inj., especially used ones, get them flowed and clean. Last think you want is thinking that upgraded injectors flowing less and detonate your engine because you wanted to save $50 on cleaning and flowing.



Go check RC engineering for more info. They bore out stock injectors and also service them.. There are also cheaper places around.. who might do as good of a job.

where can i find rails and 4 1680 injectors i tried looking and had no luck

www.kgparts.com, rotaryextreme.com are two stores i know that sell the fuel rails.



if i were you, i would stay with smaller primary injectors to make your idle and lower rpms more managable and smoother. Unless you're shooting for unless you're shooting for way more than 400 hp, 550primary or 850 primary and 1680cc secondaries would be sufficient.



fyi, i have 2 new 1680cc injectors that im not using right now, we can make a deal for them if you want... shoot me a PM

Holy smokes!



Let me tell you that you need to talk to some tuners before you decide to go that large.. You just went to not knowing a thing about injectors to wanting the largest injectors on the market. Its also not easy to tune with large injectors like 4 x 1680s.



I believe that its a complete waste of money and for driveability to put FOUR (4) x 1680s because you want to make 450HP. I'm wondering what kind of power you are making now and if you have ridden in 400+RWHP FD. You might want to start thinking about what you want to do with your car. Because depend on what you are going to do with your car, you want to set it up accordingly. Just putting large injectors and thinking you could be like Crispeed isn't going to happen. Make sure you decide what you want to do with your car, ie track, drag, or just to show off your dyno charts.. think about what kind of turbo(s), mods, etc.. Because its definitely a waste to put 1680s in stock twins. Good luck! we are here to help and not to bash you.. So, hope you don't take what I say personally.. We all been there.... one point or the other.. Just trying to help you make less mistake.

i dynoed 296 whp on 14 pounds at 11.3 air\fuel with bone stock twins with the aem using boost vs fuel comp. I tuned it myself with a some help from my boss, I work for a tune shop but he dosent know much about 7s just alot about thermal dynamics and aem ems's. if u say 550 and 1680 is good then thats what im going to use.