I am wanting to know what are available in aftermarket injectors for Subies.
I have an STi V4, but have reached the limit of the factory injectors with the amount of power it is achieveing.

I have been told the factory injectors are rated at 500cc, is this correct???

I am looking for either 650cc or 720cc injectors.
Anyone had any experience with injectors of this size??

And also what does it do to the low down drivability of the car when running such large injectors??


Any info appreciated....

 

std on yours should be 440cc. Scoobymania keep a range of injectors in stock. A friend is running 740cc injectors on his car, with no driveability problems at all. The car is actually very economical when driving sensibly, and is comparable to a standard car. Perhaps some injectors are better than others, and obviously the mapping comes into play.

 

thx steve. any chance of finding out the brand of those 740cc for me??

Then I can find out if they are available in NEw Zealand...

Thanks

 

740cc are not available for the Phase 1 engine afaik, Phase 2 only, you could go to 550's or 850's (think that 660's are in there as well but v expensive)

Bob

 

I have sent you an E-mail Bob with a few questions, thx in advance for the help...

 

with a very small mod you can use the RX7 injectors, which are cheap and have a great range of sizes.

 

Hi, yeah I have a 1994 WRX which is running series 5 RX7 injectors, they are high impedance items which I got for $200 for the 4 of them, and they are rated at 550cc. Fitting them is a relativly simple task, and the plugs even matched the subaru plugs, so there was no problems there. All I had to do was fabricate some fuel rails. I also live in Hamilton, so if you are interested you could check out my setup.

 

Thx duccz, I think I might be needing slightly bigger, looking at some 720 or 740cc. Just trying to sus out the details...

 

Yeah ok sweet as , the good thing about the mazda range is that they are all interchangeable and go up to around 800cc. What kind of horsepower are you making from your engine?? I was going to go for around 700cc injectors as well, but found that 550cc can support some pretty serious ponys. According to everything I have been told your yellow STI ones are about 460cc. I think 12 a mazda injectors are about 820cc or somthing , ya might lose a bit of idle quality , then again who cares about idle ... Also what ECU are you running out of curoisty? Hrmm might be a while before I am slapping a set of 800cc squirters in.

p.s I think you can buy Apexi 720cc injectors for around $300 each.

[Edited by duczz - 8/5/2002 3:58:32 AM]

[Edited by duczz - 8/5/2002 4:00:42 AM]

 

Bob, is there a difference between the Phase 1 and Phase 2 fuel injectors ?????

Carlos H.

 

duczz- have investigated and you are right the 720cc are avialable form APEXi for about $300 each. These should be ample to cater for my current and future needs.
Car is currently running 283bhp @ wheels, so its a guess at flywheel power....
Should get a good price as I might get a APEXi front mount as well....

 

Yeah I went all through the injector saga, Im not sure if the apexi ones will fit directly into your rails , it depends on the bucket size etc from memory I think I would have had to get version 5 rails if I had wanted to fit those apexi 720cc injectors, I think MacLennan's in Willis St Wellington were one of the better priced suppliers, might pay to give them a ring. the only other thing to keep in mind when buying them is to get injectors with a similar resistance to save any other headaches down the track.

 

283BHP@wheels
that must be around 370bhp at the fly

Tony

 

And weve only just begun, To quote the mighty Carpenters!!!!!!


Duccz, WHat is the story with resistance??? And why can it be a problem?? Is that electrical?

 

Mazda injectors go all the way up to 850cc, and are the easiest to fit to Subarus

 

I agree with subman, mazda injectors are by far the cheapest option available and are almost indentical in shape as items that you will pay big bucks for new. Determining the right amount of injector fuel flow is only part of injection selection process. You also have to match the injector’s operating parameters to your ECU. Basically to cut a long story short Injectors come in two main types, either saturated circuit injectors or peak and hold injectors, the first one being high resistance (12 - 16 Ohms)and the latter being low resistance (2 - 5 Ohms) Subaru's like most production cars use High resistance due to their relativly low cost and reliability, while alot of high performance after market systems go for the low resistance peak and hold injectors.
As far as you are concerned when it comes to installing new injectors It is possible to use high resistance injectors in a low resistance system. However it is NOT possible to use low resistance injectors in a high resistancesystem (simple circuits too much current flow = fried injector drivers ( ECU damage!!)
The beauty of using Nippon Denso Mazda injectors ex Mazda RX7 is both high and low resistance are commonly avaliable so you can very easily get the correct ones, If however you find some low resistance injectors which you really want you can still fit these to a high resistance circuit with the addition of a resistor, but it saves alot of messing around if you get the right ones to begin with!

 

Have all the STI's version III - VII high resistance? Because I just bought injectors from a STI III. It has to put on a WRX of 1998 (phase 1) Will this fit without any problems??

Regards Mike

 

i have 850cc injectors on my beast

 

FAO Paul
Pics of my phase 2 fuel rails, on my legacy, with the yellow 440cc injectors.
Note the Phase 2 inj wiring plug sits straight, although irrelevant

I cut, and flared the fuel pipe to suit myself, as the solid pipes dont really go where you would like, coz of the different manifold.



This is the fuel rails as fitted to the MY00 manifold

 

thanks stevie