is there a way to tell what % you are at ? im curious to know how far im pushing my stock injectors with the HP im putting out. im running vortech with 3.12 pulley and some other mods, currently 400 hp and 342 tq. wondering how much im pushing the stock injectors.

 

You are most certainly at 100%. The stock 280cc injectors are good to about 280-300 HP at a normal fuel pressure.

 

I was tossing the idea of going with the 380cc injectors. I dont think you would have to tune too much, and i beleive they drop right in with the oem hardware.

 

I have a set of 380's from my Turbonetics kit for sale if your interested. Plug n' play. Used for about 2 months.

Wow.... you're really pushing those injectors. 342 rwhp on stock injectors? Yikes. Which engine managment are you using?

Respect
JET

 

400 wheel hp on stock injectors, aux fuel pump and fmu from vortech though, im not sure if this changes it.

 

Damn... How much boost are you running?

 

Holy...... I have 440's maxed out at 80% and I'm making 410 rwhp.

280's?

Better buy my injectors! No.... seriously. BUY MY F*CKIN INJECTORS or else.

Respect
JET

 

There are a lot more factors involved in injector sizing than simple whp figures. Also, I wouldn't consider 80% "maxed"...

Agreed that it would be a good safety measure to up the injector size and retune. But, if he is in a safe AFR range and not experiencing detonation after extended heated conditions and in the summer, then it sounds okay to me.

 

Just the amount of boost he's running makes the injectors effectively smaller than 280's. I can't imagine using 280cc injectors to make that power.

80% keeps the injectors cool and optimizes lifespan. That's the zone the injectors were designed to be run in.

Respect
JET

 

Greddy Infometer

or Blitz r-vit

Both will tell you this

 

You have to remember that the Vortech kit raises fuel preasure at a rate of 8 to 1 . So at 9psi the fuel preasure is upwards of 120psi . So the fuel injector isnt open 100 % of the time . ANd it may not even be open 80 % of the time . You also have to remember the wide range of whp people have on the 3.12 pulley because of different dynoes

 

so you are saying that because of the FMU from vortech it will allow more fuel to be pushed without maxing out the injectors ?

 

It isnt the ideal set up for sure . But it works . If you take an injector and pulse it for 1/10 of a second at 52 psi of fuel preasure and then do it again at 120psi of fuel preasure , you'll get alot more fuel the second time . DO you have your R4 file . If so look at your fuel map . If the numbers in the upper rpm and boost cells are below 10 , you havent maxed them out , and I dont know if they were even at 10 or a little above , if you would be maxing them out .

 

thanks boog, i looked the map and the highest number is 9, in my high rpm/boost range. in the lower rpm range, 4k rpm at 4 psi it's showing 10.6 on the fuel map. is the lower rpm range safer to go above 10 as it should have less stress on the engine ?

 

10 represents NO change to what the ECU is telling the injector to pulse at . Ive seen some R4 maps with numbers in the 11's with the stock pulley on . Remember some of the guys are running the 2.87 pulley and still on the stock kit .
If you do want to go to bigger injectors to be safer . You will have to go to the Walbro pump and or a smaller washer in the FMU , so the fuel preasure doesnt rise as much

 

my plan is to go big, 2.87, upgraded blower (t-trim), larger injectors with walbro fuel pump, and utec, just wondering how bad im doing now with my injectors being stock.

 

If you are already going to spend that much money you might as well get some bigger injectors for an extra $550. You might be able to find some RC 550's in the classifieds. I sold mine just a few weeks ago for $425. They were used for 5K miles.

 

i am, i put that in the post you quoted. i have a friend that is selling some RC 550's for 350

 

Any plans to build the motor ?

 

I might have some nearly new 650's if you need them. They were in the car for less than 1000miles. Moving up to 750;s.