Subaru WRX Forum banner

03 WRX question-max injector size with stock turbo

4K views 5 replies 4 participants last post by  03wrexx 
#1 ·
Interested in upgrading injectors and curious whats the largest cc's that benefit a 2.0l/stock turbo?
I will not be racing and I dont plan on maxing out. Any info/opinions/links is greatly appreciated.
 
#3 ·
Your car already has the injector which most smoothly delivers the amount of fuel that the ecu requires for the given amount of air available and the throttle input it is receiving will determine that rich/lean level, and also airflow into the throttle.

Increasing the available fuel assumes you will also be increasing air flow, ie; larger turbo and pipes.

Also, to benefit from larger injectors, you will want a larger pump. The small Subaru pump cannot keep up with the demands of a reasonably upgraded fueling system.

What other modifications are you doing along with this?

There are several levels of injectors, and several levels of pumps, but all of what you choose should be planned together...

for example... you want ^Z amount of power...
that requires ^X amount of air and ^Y amount of fuel
balancing for ^X means a very efficient turbine, and pipes to move air for it the best way possible.
^this is not cheap, and takes some knowhow, which really isn't entirely rocket science, but it mostly is...
this basically means you can get away with 180hp without a lot of finicky or expensive stuff ...maybe even 200hp... but I'd be looking at the whole system together, and all the plans should be laid out at once. It will take $500 to get over the 250hp point, $750 can net you 275hp with the right shopping finesse, like a bargain intercooler (not an ebay crap one, i mean a used process west or grimmspeed unit) and maybe even a used turbo if it's not beat w lots of shaft play.... those will make wanting pump and injectors functional... i hope this makes sense.

If you have a list of planned mods, or parts already ready to install, injectors can be had from injector dynamics.
they make a reliable replacement and a very fine upgrade.
you can run as large an injector as you like, the ecu will still feed the same amount of fuel and compensate for the A/F the same as it did, you will simply have massive headroom if you buy giant ones, and maybe have some linearity issues.
It's good to stay within a certain range for each power level, i think there's a chart around somewhere as to what injector is best for what power level we ask of our engines, most techs have their own kind of 'rules of thumb for injector sizes' which i do, but i refuse to let my opinion blow your engine.

tell us what your total end goal is, and im sure we can be able to tell you a good pick that will match the setup you want.
 
#4 · (Edited)
Injectors alone? No plans to change the turbo?
I am set on a big 16g-xtr, but not until I can afford quality, which is in the $1,500 range.

tell us what your total end goal is, and im sure we can be able to tell you a good pick that will match the setup you want.
I have a hi-flo catted downpipe and SR*S Type R? 3" exhaust. It's quieter like the Cobb. SPT intake on and silicone turbo inlet in hand to be installed.
I have an ebay jumbo TMIC and it could fit better but so far working fine. NO BOV! :nono:
I am sending out a Greddy catless uppipe for ceramic coating before installing and I dont intend on doing any aftermarket exhaust manifold or external wastegate(not for a long time if at all).
I have the V3 AccessPort and their Stage 2 MAP is working fine. First week of the Stage 2, numbers were a little off, but things slowly moved to correct levels IE: DAM, A/F Learning, Fine Knock, etc. The V3 is nice because you can split-screen the gauges and have up to 6 monitors(your choice what to monitor) on 1 screen.
I was cruising home after shooting a race and on a steep highway upgrade at about 60mph, I downshifted to 4th and floored it pumping out a max 18.91psi.
I did my research about the "pinks" and they are my most likely choice, with a new Walbro 255 of course.
I posted a thread asking about the difference between non and Cobb spec pinks. What a scam...
I was curious if any of the Suby fanatics here attempted to max a stock turbo and what their results were.
 
#5 ·
I suspect you will be less troubled if you wait until you swap turbos to swap injectors. I think your IDC data will tell you this better than anyone could though.

Several members have gotten as much out of a stock turbo as they could, and the difference becomes things like whether they used MeOH or not etc. Have a look at build threads.
 
#6 ·
I agree, if i were you i would save up and just buy the parts and store them until i had everything. Because if you get injectors you have to tune it, then if you get a turbo you have to tune it again. So better just to get everything installed and tuned at once. Also some good injectors would be (STI Pinks, or Dark Blues) i have some pinks and there are AWESOME, with a vf34 turbo. just a suggestion..
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top