maxing out 720cc Injector + walbro 255lph combo (fuel pressure)
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maxing out 720cc Injector + walbro 255lph combo (fuel pressure)
What fuel pressure should I run my setup at to get the most fuel out of it? I dont want my pump to not be able to push the pressure but i want enough pressure to spray more fuel. any suggestions?
basic math says 720*4(injectors)*(unit conversion) = 172.8lph.
so the injectors are maxing out before the fuel pump, but what fuel pressure are the injectors rated at and what fuel pressures are the fuel pumps rated at?
Thanks.
I found this: (i have the HP)
from here: http://www.lightningmotorsport...h.htm
some descent info ^^
so i did some calcs on that pic, with the HP, i got the following numbers:
@40psi: (40*60) = 2400 "fuel units"
@50psi: 50 * 56 = 2800
@60: 60 * 51 = 3060
@70: 70 * 47 = 3290
@80: 80 * 43 = 3440
@90: 3420
@100: 3500
@110: 3190
So i guess bring your fuel pressure up to 100 if you have to (and your FPR will hold it), but at 110 it will fall. Looks like I answered my own question .
Modified by Cyphear at 3:06 PM 1/12/2005
basic math says 720*4(injectors)*(unit conversion) = 172.8lph.
so the injectors are maxing out before the fuel pump, but what fuel pressure are the injectors rated at and what fuel pressures are the fuel pumps rated at?
Thanks.
I found this: (i have the HP)
from here: http://www.lightningmotorsport...h.htm
some descent info ^^
so i did some calcs on that pic, with the HP, i got the following numbers:
@40psi: (40*60) = 2400 "fuel units"
@50psi: 50 * 56 = 2800
@60: 60 * 51 = 3060
@70: 70 * 47 = 3290
@80: 80 * 43 = 3440
@90: 3420
@100: 3500
@110: 3190
So i guess bring your fuel pressure up to 100 if you have to (and your FPR will hold it), but at 110 it will fall. Looks like I answered my own question .
Modified by Cyphear at 3:06 PM 1/12/2005
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Re: maxing out 720cc Injector + walbro 255lph combo (Cyphear)
injectors are rated at 3bar pressrue 43.5 psi approx. Most fuel pump are rated in GPH or LPH depending on which company and area you live in.
In your example you would want to set your base static pressrue around 35 on the FPR and boost with a 1:1 regulator you are can take it up lets say max of 30psi
that would make your new fuel pressure at full boost 65psi which is well within the ranges of the walbro 255lph
In your example you would want to set your base static pressrue around 35 on the FPR and boost with a 1:1 regulator you are can take it up lets say max of 30psi
that would make your new fuel pressure at full boost 65psi which is well within the ranges of the walbro 255lph
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Re: maxing out 720cc Injector + walbro 255lph combo (b18bturbo)
Thanks. So i think i'll try ~55psi base + 20psi of boost = 75psi total pressure. should be good.
PMed about a fan
PMed about a fan
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Re: maxing out 720cc Injector + walbro 255lph combo (Cyphear)
you dont need that much base pressure on a 750cc injector i would go with a smaller base pressure and then run it that way your idel tuning will be alot easier
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Re: maxing out 720cc Injector + walbro 255lph combo (b18bturbo)
they are almost maxed out right now. looks like they will max out at around 22psi of boost @ at stock fuel pressure (45psi when i had a gauge on it).
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Re: maxing out 720cc Injector + walbro 255lph combo (Cyphear)
if your injectors are maxing at 100% duty cylce at that low of boost on 780cc what power are you pushing down at 22psi
then the problem could be your injectors you have are nto flowing correctly
then the problem could be your injectors you have are nto flowing correctly
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Re: maxing out 720cc Injector + walbro 255lph combo (b18bturbo)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b18bturbo »</TD></TR><TR><TD CLASS="quote">if your injectors are maxing at 100% duty cylce at that low of boost on 780cc what power are you pushing down at 22psi
then the problem could be your injectors you have are nto flowing correctly </TD></TR></TABLE>
they are 720's. well, im getting near 100%, acording to uberdata, but i've also heard the uberdata duty cycle #'s are 10-20% off. anyway, its a 2.0L LS, making ~425whp (just a guess). they were balanced and tested by RC before i bought them.
then the problem could be your injectors you have are nto flowing correctly </TD></TR></TABLE>
they are 720's. well, im getting near 100%, acording to uberdata, but i've also heard the uberdata duty cycle #'s are 10-20% off. anyway, its a 2.0L LS, making ~425whp (just a guess). they were balanced and tested by RC before i bought them.
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fyi
i had dsm 450's with a adj. fpr, i set fuel pressure to a base 70psi, and i was able to run 17psi on my drag t3/t4b, duty cycle was almost 75%. i also had a 255 high pressure walbro intank pump. btw.....this is according to AEM EMS datalogs.
i had dsm 450's with a adj. fpr, i set fuel pressure to a base 70psi, and i was able to run 17psi on my drag t3/t4b, duty cycle was almost 75%. i also had a 255 high pressure walbro intank pump. btw.....this is according to AEM EMS datalogs.
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Re: (Hella_JDM)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Hella_JDM »</TD></TR><TR><TD CLASS="quote">base pressure 70 good ******* god!</TD></TR></TABLE>
damn right 70 psi is a little for a base.
damn right 70 psi is a little for a base.
#11
Re: maxing out 720cc Injector + walbro 255lph combo (Cyphear)
yeah i agree with that my base pressure is at 70 also with a walbro 255 rc 400cc so it can take it the only thing is make sure to change to a stronger line on the fmu
#12
Re: maxing out 720cc Injector + walbro 255lph combo (Cyphear)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Cyphear »</TD></TR><TR><TD CLASS="quote">
they were balanced and tested by RC before i bought them.</TD></TR></TABLE>
is it a street car? running a huge base pressure could be an issue with the injector response.
they were balanced and tested by RC before i bought them.</TD></TR></TABLE>
is it a street car? running a huge base pressure could be an issue with the injector response.
#14
Re: maxing out 720cc Injector + walbro 255lph combo (Cyphear)
i'm no engineer, so double-check everything i post and everything else you read on the 'net.
basically, it's when the fuel pressure exceeds the opening pressure of the injector... the injector response could become non-linear at higher fuel pressures.
rc can tell you what the fuel pressure limits of your injectors are... fwiw, some people believe that base fuel pressures of 60psi are a realistic limit, depending on what the fuel pump can handle... make sure that you have full voltage and current capability present at the pump.
increasing fuel pressure isn't very efficient... in order to double the fuel flow, you have to quadruple the fuel pressure(?).
basically, it's when the fuel pressure exceeds the opening pressure of the injector... the injector response could become non-linear at higher fuel pressures.
rc can tell you what the fuel pressure limits of your injectors are... fwiw, some people believe that base fuel pressures of 60psi are a realistic limit, depending on what the fuel pump can handle... make sure that you have full voltage and current capability present at the pump.
increasing fuel pressure isn't very efficient... in order to double the fuel flow, you have to quadruple the fuel pressure(?).
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Re: maxing out 720cc Injector + walbro 255lph combo (ludesleep)
I know from the info Seimens gives to OEM's on their Deka injectors (ball-style, mostly low-z, high flow), they can take up to 105psi. I would imagine it will be similar for most of the higher flow ball and disc-type injectors.
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