I am planning on upgrading my fuel injectors. I am running 13lbs on the stock ones now. I want to be able to run 14-15lbs. I have a bigger fuel pump, and lots of nice upgrades. I think it was rx7.com that told me all I have to do is upgrade my primaries to 850cc injectors. Does this sound right? if so would these work for what I need?

http://cgi.ebay.com/ebaymotors/ws/eB...spagename=WDVW

Help me out. thanks

 

Bump... help!

 

Read this.... http://www.wvinter.net/~flanham/wlan...el/850pri.html

 

so am I right to upgrade too 850cc primaries, to make 15lbs of boost?

 

I would change the secondary's to 1200 or 1300..

 

just get those and send them out to rc to get bored to 1300

 

Not sure why you even need to, if you are still using the stock turbos. I ran 15psi putting down 340 rwhp on stock injectors, never had a problem. This was even on stock FP.

 

Yes, you'll be fine. The older ECU's didn't do so well with 850's in the primaries so upgrading the secondaries was always a better fit. The newer ECU's (PFC, etc) can be tuned very well to deal with 850's primaries; he only problem being the milling of the primary fuel rail.

Search for Garfinkle, he does the modifications to the primary rail for a good price.

 

If you only want to run 15 lbs of boost, there is no reason at all to touch your stock injectors.

 

hmm, but wouldnt I be running very high duty cycles? Is it bad to run high duty cycles? I am new to the fuel system aspect. My injectors have 47k miles on them. RX-7.com told me that 850cc primarys would be a good idea, and he said you would not have to modify the fuel rail. He was also telling me that he can sell me a interface that hooks my car to my labtop, and I can download the right setup to my car. That is pretty frickin cool. Sorry if im a little behind. Does anyone do this?

 

I want to be as safe as possible, but I also like the idea of a little more boost. Is 15lbs of boost pushin the little twins too hard?

 

Check this thread:
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/what-situation-do-you-have-259912/

 

Very interesting thread Mahjik.. By the way you are the man! I am guessing i need some pretty good tuning to be able to overcome the high duty cycles though. I am running 13lbs, and I forget what my duty cycles where, but they were getting up there. From what it seems High Duty Cycles are not as important as A/F, and from what you said "never heard anyone that has blow an engine due to high duty cycles" mabe I will just get it re tuned with my stockers. I want a reason to re-dyno it anyways I added the efini y-pipe, and power pulleys. I figure with 14lbs of boost, and these extra mods I should be closer to 300rwhp. At least I would hope so.

 

my car is topped out at 12psi on stock twins, my inj duty cycle is in the low 90's. lucky i have the pfc and supra fuel pump, but i will be upgrading the secondaries to 1300 very soon, i don't like duty cycles that high at all. I can't turn down the boost either because my wastegates arent ported, i'm stuck at 12 psi. (don't worry, i have no boost creep at all)

 

Mahjik if I were to decide on getting new injectors. What would be the best, and easiest way to go about it. How big? Secondary, or primary?

 

The easiest way is to have your secondaries bored out larger. This way there is no modifications to the fuel rail and nothing needs to be replaced. I believe you can buy new 1200cc injectors or have some 850's bored out to 1300's. Some people have reported problems with bored out injectors so the 1200's might seem attractive if you aren't trying for some 500hp monster car.

 

so your saying that 1200cc secondaries would be a nice upgrade, and give me what I want?

 

If you are looking to have more safety running 14-15 PSI, then yes.

 

Very good, Thank You!