si_blues

I have a guy building my motor and installing turbo kit and telling me I need a 1 to 1 fmu. But everyone else says I dont need a fmu but I need a fuel pressure regulator instead. I'm running a si b16 with t3t4 vafc and 450's .I was told to get a 1 to 1 fmu and I cant find one anywhere, PLEASE HELP

Sohc Driver

There's no such thing as a 1 to 1 FMU. They do make 12:1, 10:1, and 8:1 calibrated FMU's however.

To answer your question on needing an FMU or not, there is a yes and no answer, depending on what kind of fuel management route you are going with. If you decided to run the AFC hack then no. All you need is the VAFC, 450cc injectors, and an 255lph intank fuel pump. It looks to me that since your "guy" that is building your motor says he's not using an FMU...he's more than likely going with the AFC hack.

The FMU route however, you technically don't have to run a VAFC for it to work, but the VAFC can help you fine tune. With an FMU setup, you'd need the FMU, a missing link, and a inline high pressure fuel pump. Since you already have 450cc injectors...you'd probably want to run a 10:1 calibrated FMU and use the VAFC to fine tune the Air/Fuel ratio.

Khoi

si_blues

this guy is wanting an fmu but he wants a 1 to 1 but there isnt one

beepy

Wouldn't a 1:1 FMU just overcome the loss in fuel flow from spraying into a pressurized manifold?

They really should make something like that. Even with good injectors it would be nice to maintain 44 psi above manifold pressure in the rail.

Bailhatch

I beleive the stock fuel pressure regulator is a 1:1

gritsak

the aeromotive FPR one everyone uses is 1:1..since you have upgraded injectors and a 255 i would just get a AFPR...you will of course need to get the car tuned

Boltz

1:1 is just a normal FPR

beepy

Damn. Wish I had a FPR. (Stupid pulse-regulated fuel pump)

si_blues

appreciate it I had no clue what he needed a 1:1 for, with 450's a 255 and vafc I shouldnt need one. I can see a fpr maybe

DaX

iTrader: (1)

AEM, Aeromotive, OEM, Paxton...all of these are 1:1 Fuel Pressure Regulators.

Casey

iTrader: (5)

whats up chris? its casey(obviously) anyway, i dont know what rob told you but with the 440 injectors you should be able to just tune some fuel out on your afc. call mark at turbo tune and tell him what your deal is and hell tell you what to set your fuel at till you can go get it dyno tuned by him

TECH43 RACING INC.

you can't run a fmu, with 440's, on a street engine. way too rich.


440's + tunable management = ok

240's-270's-310's(310's wont idle great) + fmu = ok. 240's and a 10/12 to 1 works good for most street applications.

440's + fmu = bad news


BTW...if you use a 255 lph pump, you HAVE to use a regulator that has a large return orifice. Stock or b&m will not work. you can use aem, aeromotive, sx, etc.

Casey

iTrader: (5)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TECH43 RACING INC. &raquo;</TD></TR><TR><TD CLASS="quote">

BTW...if you use a 255 lph pump, you HAVE to use a regulator that has a large return orifice. Stock or b&m will not work. you can use aem, aeromotive, sx, etc. </TD></TR></TABLE>

y is this? i used a b&m on my NA motor with stock injectors and 450 dsms with my 255 pump

TECH43 RACING INC.

its too much volume and pressure for the stock regulator to handle. it cant return enough. install a 255 on a car with a stock regulator/b&m, and watch the fuel pressure instantly increase appx 25 psi, and thats with the regulator backed out all the way.

there are two ways to get fuel under boost.

1. larger than stock injectors, w/ an adjustable injector duty cycle (management). as the ecu reads boost, it increases pulsewidth to the injector.

2. small injectors (usually stock, or slightly bigger) w/ a boost dependent regulator (fmu)

the ecu fires the injectors using an n/a fuel curve(it cant read boost) when the engine goes beyond zero vacuum, the fmu takes over, increasing fuel pressure as boost pressure increases. ie: 12 to 1 fmu, increases fuel pressure 12 psi, for every 1 lb of boost it sees. the engine is getting the proper amount of fuel, with high pressure, instead of using low pressure, but with a larger duty cycle.


imagine the amount of fuel you would be receiving, with 440's, AND a fmu. too much.

suggestion: go to rc's website, learn about BSFC. most people dont understand it, but when you do, you'll realize how many people are going overkill on fuel injector sizing.

si_blues

I didnt think i needed it but he insists on a 1:1 fmu says it wont work without it

TECH43 RACING INC.

there is no "1:1" fmu....a normal regulator is 1:1

tell me your setup...i'll clue you in to what you should go with.

si_blues

b16a2 eagle rods, wiseco pistons 9:1, stainless valves, t3t4, walbro 255, blue top 450's, crane cams ignition with boost retard

TECH43 RACING INC.

i suggest:


255lph pump
aem regulator (or some type of big return orifice reg)
hondata, ems etc.
use your 450cc injectors
(dont use the boost retard function on your ignition)

or.

255lph pump
aem regulator (or some type of big return orifice reg)
fmu 10/12:1 (you'll need to test to see what your setup likes)
use your stock 240cc injectors, 270's if you plan on boosting over 12/13 lbs.
(use the boost retard function on your ignition)

with how cheap hondata is, i suggest you dont skimp, and get it.

si_blues

Ive already had a vafc and im gonna go that way since it will work, maybe later on I can do hondata I really cant afford it right now

TECH43 RACING INC.

vafc's dont read boost!