stock injectors on a wrx (how many cc's)

[johndoe]

I'm doing some major work on my Wrex and need to know how many cc's my stock injectors are, i'm going to 550's but i dont know it thats enough should i go 780 or 850?

How much power are you planning on making?

[johndoe]

I'm looking on making anywhere from 350 to 450 to the wheels, i already dyno'd the car at 314.5 hp to the wheels i'm looking for more power, although my machanic told me that knowing the stock injector size can help on making much more accurate Hp.

if you are already over 300 wheel horse power then odds are very high that you have maxed out your stock injectors (420cc). You can use the the STi (565) injectors. Those are good for about ~ 350whp

[johndoe]

So your 100% sure that the stock injectors are 420cc? Only b/c your the first to tell me any # on the cc size on the stock injectors. And thanks by the way

Off the top of my head, i remember reading the shop manuals, the cc's were 420. i can double check when i head back to the shop.

[johndoe]

thanks alot man i really appreciate that

[Dick Fitzwell]

i already dyno'd the car at 314.5 hp to the wheels

that's very impressive on stock injectors! i haven't seen anyone pass ~270whp with stock.

why not go with the 850's?
-DF

DF,

You are correct stock injectors will not go past 270 whp, well from my experience. I have tuned to many cars and noone makes it past that, though all stock fuel pressure and stock fuel pumps.

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Johndoe,

Also the stock fuel pump is a big problem at around 300 whp, as it can nto push anymore fuel and runs out. So you will also need to upgrade the fuel pump to at least 255lph if not bigger.

Another thing the fuel lines that run from the gas tank to the engine, are not big enough to run fuel through at around 350whp, so you will need to upgrade the fuel lines also all the way from the gas tank.

As for 350-450whp 650cc injectors will cover you for that amount, you can always raise the fuel pressure a little more, but that shoudl work fine. Just make sure it is well tuned and you have a big fuel pump, like 315lph.

johndoe,
What system are you running? i have not hears that people can get past 300 to the wheels on the stockers? I would like to do somethings like that so save a few $...