bennyhonda7

k im running dsm 450's in my a6 vitara setup and with 18psi when will these injectors typically max out?

samson

Goes by WHP and I think you should be fine, but not positive.


JP

mugenblacky16

It's all about the math baby!!! Don't look at it as psi, but rather hp goals. Also, it depends on your afr and duty cyle.
Here's an example:

1) convert from metric(cc) to standard(lbs):
In your case 450cc/10.5=42.86lb/hr

2) choose you duty cyle and # of cylinders, multiply that product by the inj flow
4(cyclinders) x 0.9(duty cycle @ 90%)=3.6 => 3.6 x 42.86=154.30

3) Divide that by your B.S.F.C.(brake specific fuel consumption). NA car use about .5 pounds of fuel/hp/hr. You're turbo, so you will be slightly higher (unless
you're running extremely lean, or running high octane fuel), around 0.6 - 0.65
154.30 / 0.6 = 257.16 horsepower max @ 90% duty cycle

You can push 450's farther with leaner(.5 bsfc) and a 100% duty cycle(1.0), but that's up to you and what you are willing to risk. I showed all the math to help with the understanding and so people can play around with different injector sizes, duty cycles, and fuel consumption(richer or leaner). If you have a hp goal in mind you can run the formula backwards to get the supporting injector size for that hp. Hope this helps.
-Andy

labatt50

check your bin (duty cycle tab) in crome/uberdata and you'll see

i would say, yes without even checking it

adam38654

Im shure you could make it to 300hp/18psi if you had the walbro high flow 225 pump, and you mite have to bump the fuel pressure up a few psi with a fpr.

mugenblacky16

Upping the fuel pressure is working against the purpose of a high flow pump. Fuel pumps flow less fuel volume at high pressures, not to mention the pump is working harder thus creating heat and heating your fuel. The whole purpose of HF pumps is to have the ability to feed the bigger injectors w/o having to up the pressure. You can probably push those injectors a little over 300hp, but that's at 100% duty and a pretty low fuel consumtion for a FI engine(on the leaner side bang, bang). You have the final call, but remember the risks. If you have the ability and the money to fix something if it goes wrong, then get alittle experimental with your ----. But if you're not rich and don't want to be fixing broken stuff, then I would step up your injectors if you're going past 300hp.

Just out of curiosity: Do you know how much hp you are making right now? and what is the air/fuel ratio @6k w/ full boost(if you have full at 6k)? Just curious.
-Andy