#17813, "OK I got another lame Fuel Pressure Question"
How much boost can you run with a stock fuel setup on a Star Kit? I have an airtex inline (makes me run super rich for the time being) fuel pump and the vortech fmu that comes with the star kit. I've heard that the next step is to upgrade injectors and get a lower disc like 8:1 or something so the fuel pressure isn't too high correct? Now what happens if it's too high!? Haha sorry for the lame questions I don't like to mess around with my fuel system but if I have to I will. Getting EGT gauge in about a week so I'm gonna be upping boost to the highest boost I can get safely
I'm running 5 psi on an intercooled star stage 1 setup. I'm guessing that I can run 7 psi since the stage 2 can run that much already. So with the 12:1 disc I'll get mega fuel pressure as I up the boost correct?
http://www.hadesomega.info -car specz and movies 95 Eclipse RS | 76' 280Z | 89' MR2 | 99 Neon | 91 Zephyr Who sez FF can't drift?
#17816, "Fuel pressure answers and figures for STAR turbo" In response to Reply # 2
I would not run 10 psi on a big E T03/04 turbo with stock injectors. I think the internals could (possibly) handle it with some ignition retard, but considering that turbo probably puts out 2-3 more HP per pound of boost than a Super 16g, at 10psi, you're probably approaching 290 HP.
Now, using the proper fuel injector formula, you can figure it out:
(290 HP x 0.525 x 10.5)/4 = 400cc @ 100% duty cycle
Assuming that 100% duty cycle is acceptable (in which it probably shouldn't be), you can figure out the fuel pressure required:
((400/235)^2 x 43.5) + 10psi = 136 psi
So all that means is that you accept the fact that your injectors will be required to be taxed to a 100% duty cycle and then squirt under at least 136 psi of fuel pressure. That's almost 30 psi more than HRC's system allows for.
Whether you want to try and do that sort of thing is up to you, but just keep it in mind when you figure out what sort of calibration disk you'll need when trying to meet your fuel needs. By the way, the correct disk would be 7.6:1 assuming that my HP figures are correct. I presumed that the T03/04 turbo provides close to 15 HP per pound of boost.
_____________________________________ Jason ESi-T
04' BMW 325Ci 91' Nissan 240SX 98' Eagle Talon ESi (sold)
#17817, "RE: Fuel pressure answers and figures for STAR turbo" In response to Reply # 3
i ran 8.5-9psi on my STAR kit with a walbro 255 intank and that airtex inline, with rich O2 voltages and good EGTs. My fuel pressure gauge reads only to 100PSI, but i found out reather quickly that that roughly 9PSI, that gauge was waaay to the right of 100psi. I guessed 120PSI, but Jason's numbers sound right.
Can it be done? I did it for 10,000 miles.
Did it run well? Like a bat out of hell.
Did it last? No. I cracked my #2 piston, but i attribute it to a loss in calibration between my TPS voltage and my SAFC - when it gets disconnected for an unknown amount of time, it "forgets" that my 3.7x voltage is 100% throttle and considers it as 78%. Never made it into my high throttle map, leaned out, cracked a piston. Oops
Do i recommend running like that? Well.. I never determined if that was exactly what stopped me. I blew. Will you? I don't know.. go find out.
______________________________ If a sentence found online has 35% misspellings or greater and includes at least two racially charged expletives, chances are it is a YouTube comment.
'95 Eclipse TurboGS (garage deco) '95 TSi AWD (restoring a survivor) '97 Talon ESi-T (poor impulse control) '99 Eclipse RS-T (daily beater) '13 Evo X (mostly stock) '17 Sienna (Middle Aged Dad Mobile)
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