Just curious what the maximum amount of boost I can run with stock injectors. I have a 255 warlboro but i dont think that means anything until i get some 720s in there.

I have a s4 t2 swap, streetported with racing beat exhaust.

For some reason 10psi sticks out in my head?

Im not going to be an idiot and crank it up to like 25 pounds ... just curious what the consencus is.

 

I think my friend cranked his ported engine to 12 or 14 and went on 100% injector duty.

 

Hmmm, 100% duty cycle....sounds like a recipie for failure, cuz if one injector so much as hiccups, it's leanville then....."boost in apex seals out"

I think I heard something about 10lbs, but I personally wouldn't go that high unless they were recently cleaned and flow tested even then . I've heard the 680's from (I can't remember which model) a Fb are a decent upgrade, 10lbs should be ok on those.

 

if i do 680 i may as well just do 720 lol

 

You can get the 680s cheap off of an 84 or 85 gsl-se.

He had a standalone and a wideband and was measuring everything, he only did it temporarily before he realized what was going on, and guy 1 was driving and guy2 was watching halwin.

He has 1600s now and a bnr stage 2.

 

DING! DING! DING!

...well, that changes everything. And do you really need 1600's for a stage 2?

 

Well, injector size means nothing without proper support for them. The stock ECU is designed to handle 550cc Injectors on an N33x ECU. On a stock ECU you will be running very rich in all other circumstance (but will be well protected in the circumstances requiring high boost). This is all taken into account if an FCD is used. The duty cycle for a 680cc injector is shorter than that of a 550cc injector, same goes for a 720. I hope you have a SaFC (I assume so but one can never assume anything, even on a street ported engine). Point being, running larger injectors will require a controller for said injectors. Let someone who knows something about this jump in anytime (and teach me too, because this is what I have gathered from several searches regarding such said information in previous encounters) and save my dumb ***. I apologize to the forums if this information is in fact incorrect.


But, bottom line is if I were you, I would run a fuel controller to safely control those injectors, regardless of size.

 

thats a whole other argument regarding fuel systems and upgrades.

i was simply asking what i could do on the stock setup

 

unW7WZ said it best. The stock ECU preforms best at stock. Period. Unless you have a fuel computer, you are heading for a rebuild.

And to answer your question sharingan 19, 1600cc's aren't necessary for a BNR stage 2. 720cc primaries and 1000 secondaries with an RTEK should be sufficient.

 

****, you can run 720s all the way around safely with a stage 2. no real need for 1000cc secondaries...

And BTW, 680cc injectors actually flow more like 718cc...

Oh yeah. I run 12 psi on stock injectors...but I have a microtech...

EMS FTW!

 

+1
i'm running my BNR stage II and ported engine with 550prim. and 800sec. at 11psi! i controll them with the SAFC and it's just perfect!

 

hmm i gotta pretty nooby question here:

racingbeat claims that their exhaust system automatically raises the boost ( i guess due to it being less restrictive on the turbo) to around 10-11 psi. they also recommend to buy their fuel cutoff eliminator. now if i were to get this exhaust and this eliminator, do i also need to upgrade injectors or am i fine? if i do need to upgrade injectors, is there any aftermarket fuel management system i need to invest in as well?

 

your fine with the exhaust

 

sweeeeeeeet!

 

i have a similar question:

Right now i'm running 8 pounds of boost. my motor is rebuilt and street ported, it has a corksport downpipe into a racing beat exhaust.. my injectors were just flowtested and everything. I want to keep the stock turbo on the car, but i also want to see how much power i can get out of it. is it a good idea to upgrade the injectors and get a fuel computer?? I want to have a decent amount of power, but i dont want to 'max' out the turbo.. what should i do?

 

8 lbs should be good on your injectors. And yes, you should get a fuel controller.

 

Well, IIRC, you can squeeze out about 250 wheel on the stock turbo...

That's about what I'm pushing on the tiny stocker at the moment. But I figure that if you're going to run that turbo to near max capacity for 250hp, you may as well get a bigger one and run it at low boost...less strain in my opinion...

 

haha yeah but that kind of contradicts my whole question.. i am satisfied with the stock turbo. with me not upgrading the injectors yet, how much hp do i have, you think (at a solid 8lbs of boost , btw)?

 

i got 193whp street ported running 5psi(stock) and 220whp @7psi

 

Nobody has mentioned another inexpensive mod.
A rising rate fuel pressure regulator will push more fuel through the injectors as the boost rises.
It's crude, but you can run ~12PSI.
At that point you start to hit the limits of the TMIC.