fmu question

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Old Jun 22, 2007 | 05:05 AM
  #1  
integraRS-T's Avatar
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Default fmu question

if u have a boosted and tuned car and u wanna up the boost can u add a fmu licke blox or obx to make up or u need to retune?
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Old Jun 22, 2007 | 05:10 AM
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retune with proper engine management your car wont last long on a FMU.
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Old Jun 22, 2007 | 03:09 PM
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where do you guys get these info from?

ive been hearing that fmu will kill your motor and stuff all the time

im not saying its the best, but when me and my bro boosted his gsr, we used a fmu for almost 2 years.

motor held up fine, but gas milage did suffer.

we did eventually go with crome. the motor is still healthy and running good as hell.

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Old Jun 22, 2007 | 03:12 PM
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Default Re: (Sic_DA_Nine)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Sic_DA_Nine &raquo;</TD></TR><TR><TD CLASS="quote">where do you guys get these info from?

ive been hearing that fmu will kill your motor and stuff all the time

im not saying its the best, but when me and my bro boosted his gsr, we used a fmu for almost 2 years.

motor held up fine, but gas milage did suffer.

we did eventually go with crome. the motor is still healthy and running good as hell.

</TD></TR></TABLE>


reread his post.

NO IT WONT....... RETUNE IT!


FMU works "OK" for low boost
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Old Jun 22, 2007 | 04:45 PM
  #5  
Sic_DA_Nine's Avatar
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Default Re: (WalkerGSR1)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by WalkerGSR1 &raquo;</TD></TR><TR><TD CLASS="quote">your car wont last long on a FMU.</TD></TR></TABLE>

talkin bout this
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Old Jun 22, 2007 | 05:39 PM
  #6  
boostedcivicsir's Avatar
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Default Re: (Sic_DA_Nine)

ok here we go.

and FMU alone will not kill an engine. goodfellas type r had one i did on a drag kit for 4 years no issues. he did outgrow it though.

the FMU will raise the volume of fuel needed, BUT it does it as a pressure increase. what kills engines, is high boost on an FMU BECAUSE there is nothing to knock back the timming.

99lspwr, frank has an insane setup that has worked for him. 10-12:1 cant remember, fmu, 310's, inline, and a btm and it works for him. running like 15 psi?

with all the management options nowadays, it is stupid to NOT go with some type of management.

to answer the question, if it is boosted and tuned, if you arent out of injector, meaning there is still fuel left to use, to upthe boost safely, you need a retune. putting an fmu on a tuned car, will throw the fuel map way out of wack.
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Old Jun 22, 2007 | 06:36 PM
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mtber's Avatar
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Default Re: fmu question (rsracer)

What is an fmu?:
A Fuel Management Unit (FMU) is a special rising rate fuel pressure regulator placed in the fuel return line of the fuel injection system. This is a very common approach to handling the increased fuel demand required by turbo kits and supercharger kits. It does work. It will make the injectors flow more fuel than their rating. These are used in addition to the factory or aftermarket fuel pressure regulator and only have an affect under boost.
FMUS are rated by the ratio of fuel pressure to boost pressure. For instance, a 10:1 FMU will give you 100psi fuel pressure at 10 psi boost pressure.

Why you shouldn't run an fmu/missing link?:
Fmu's are considered a "hack" they overload your injectors with high fuel pressure to compensate for boost pressure. This is the improper solution for fuel management on a forced induction vehicle. Most stock engine computers do not retard timing under boost hence causing dangerous engine conditions. A missing link simply stops the manifold pressure sensor from seeing positive pressure, hence preventing a check engine light.

Read more: http://phearable.net/tech/efibeginnerguide.html
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Old Jun 24, 2007 | 06:22 AM
  #8  
integraRS-T's Avatar
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so a fmu will jack up the fuel pres. but wont curve ur timming so that does mean ur engine can tacke a ****
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Old Jun 24, 2007 | 06:28 AM
  #9  
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Default Re: (rsracer)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rsracer &raquo;</TD></TR><TR><TD CLASS="quote">so a fmu will jack up the fuel pres. but wont curve ur timming so that does mean ur engine can tacke a ****</TD></TR></TABLE>

at high boost yes.
but if moderate boost, and the dizzy is knocked back a degree or 2, it can be ok. not great, but ok.
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Old Jun 26, 2007 | 07:48 AM
  #10  
hotimportcrx's Avatar
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Default Re: (boostedcivicsir)

Fmu's are ok for somebody running 7psi on a t3 saab turbo, but if chrome or even uberdata is free why not take advantage of it? The thing that gets me is if your going to spend all this money to turbo your car, Why cheap out at the end? Without a real tune there is no ignition adjustability which is dangerous and there is no IAT sensor correction for the amount of fuel going to your motor. So basically, during the summer months when its 100 degrees out and during the winter when its 10 degrees out the Fmu will still send the same amount of fuel when it should be different amounts. Just spend the extra money to get your Ecu socketed, chipped, and tuned. You will be happier in the end.
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