I'm getting ready to upgrade my injectors. I'm also going to get a Walbro 255 lph fuel pump, and an Apex'i S-AFC II. My question is, should I go ahead and upgrade all 4 injectors to 720s, or just get 720 secondaries right now. I plan on getting a stage 4 upgrade on a turbo I bought, and I figured when I got that, I could upgrade my secondaries to 1000cc or 1600cc, whatever was necessary. Does anyone have opinions?

 

I would more likely go with 720 primaries and 1600 secondaries. I am running 720 primaries and 890 secondaries, and with the stage 4 @ 15 PSI, I am almost out of fuel.

 

I haven't got the stage 4 yet. I was just wondering if I should get 720s for all 4 now, or just get 2, put them in the secondaries right now, then put them in the primaries when I get the 1600s.

Or should I better yet just go ahead and get 720 primaries and 1600 secondaries, and have the SAFC tuned to where I need it on the stock turbo?

 

when do you plan on getting the stage 4?

if its soon then upgrade all 4. 2x720 and 2x1600

or if its not for a while..say several months away just get 2 720s and put them in the secondary then when you get your stage 4 get the 1600's and put your 720s as your primary.

btw i think 1600 is WAY too big to have for a stock turbo. too much fuel.

 

Well, it will more than likely be a two to three months before I get the stage 4. I've already got the S5 turbo ready for upgrading, I just have to get the money to have it upgraded.

So at this point, my best bet would be just go ahead and get 2 720s for my secondaries, then, whenever I get the stage 4, go ahead then and get the 1600s, move the 720s to primaries, and put the 1600s in as secondaries.

Another thing I've been meaning to ask, is the wastegate actuator on the manifold, or is it on the turbo? I was wondering, because the turbo I bought didn't have the actuator on it.

 

With an SAFC you can only control up to 3300cc's of fuel. The combination is up to you, but for tuning purposes you'll want them to as equal in size as possible.

If you are dead set on running the stock ecu on such a large turbo, I'd reccomend 4 x 850cc injectors. With the safc at -50 percent on your low map, you'll almost be back to stock mixtures. Keep in mind that when you alter the AFM signal to such a large degree, the ignition timing will be affected as well.

I really think you should check out the e-manage if you're not going to go stand alone.

 

Well, I can't really afford a stand alone, so I was going to just stick with the S-AFC II, hoping that I could manage the fuel I was needing.

I'm pretty sure now that I'm going with 720s in the secondaries for now, then go ahead and stick those in the primaries when I get the stage 4, and getting 1600s then for the secondaries then.

Honestly, would a stand-alone be my best bet? What stand-alone would everyone recommend?

 

That much fuel is simply beyond the capabilities of the safc. Underneath the fancy display, all the safc does is alter the afm voltage signal. It can do this at multiple rpm points, (8 or 16 depending on which version you purchase) and can adjust the afm signal up to +-50 percent. The stock fuel injectors are 550cc.

550 x 4 = 2200cc's of fuel

Given that the safc can adjust the afm signal up to 50 percent, we know that we could run 150 percent larger injectors and dial it back to stock like mixtures.

2200 x 1.5 = 3300cc

There are a variety of combinations that would achieve this, but it's easier to tune a safc with equal sized injectors.

You must consider what sort of power you are shooting for. A stand alone would be better on any set up; but that doesn't mean that you need one. Asking which stand alone is the best will net you a different answer depending on you ask. There are a variety of options:
wolf, haltech, and microtech offer ems' that are both popular and relatively affordable.

 

which standalone is actually just depends on the turner
other than that it dont really makes a difference

 

Dont you need a different fuel rail for 1600's also?

 

Well, the power range I'm going for is right around 350-400 to the wheels. The only thing is with a stand alone, I really can't afford one, unless I can get a used one. I've looked at a lot of different ones, I just need to find one that will not only fit what I want, but fit my budget as well.

 

I just know that what I want is an LS1 eater...that's it. That's the power range I'm going for