hi
until i dont get my car tuned with hondata im planning on runnin an fmu along with a walbro 255, will it be possible to run around 9psi. now will i possible with out causing damage and would it be better to use the 10:1 fmu in that case giving it slightly less fuel?
how much psi can i take it with an fmu on a t3/t4e?

 

they both are unreliable,
but i'd rather run a 10:1
people run pig rich with 12:1's

just my opinion tho

 

i wouldnt attempt running an fmu with that much boost.
but to answer your question, honestly it doesnt matter...youre fuel pump can push out that much pressure anwyay. 10x12+45psi=165psi....i dont think thats gonna happen

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 99B16Si &raquo;</TD></TR><TR><TD CLASS="quote">i wouldnt attempt running an fmu with that much boost.
but to answer your question, honestly it doesnt matter...youre fuel pump can push out that much pressure anwyay. 10x12+45psi=165psi....i dont think thats gonna happen</TD></TR></TABLE>

His right, I blew my ringlands at 8.8-9psi with a 12:1 fmu and fuel pump with stock injectors... I wouldn't attempt it

 

FMU calibration should not be based on how much boost you are running..but rather on the size of your injectors. If you plan to run stock injectors...you need to run a 12:1 FMU. If you plan to run larger injectors say like 310 or 440s...a 10:1 FMU is what you would want to run. But like everyone else who have said it...9psi on an FMU is risky. Especially if you plan to run with stock 240cc injectors.

Reason being is because the FMU setup relies on increasing fuel pressure to the injectors in order to provide the extra fuel. The problem with that and running stock 240cc injectors is that you are overworking them. Which could then lead to injector failure later on down the road. So....if you do plan on running stock injectors with the 12:1 FMU...you'd be pushing 12psi of fuel to the injectors per 1psi of boost. So with 9psi..you'd be running an extra 108psi of fuel pressure to the injectors on to of whatever the stock pressure is at the injectors stock. You may even ask..well..why don't I just run a 10:1 FMU with my stock injectors..this would help right?? Wrong..because you may not be increasing enough fuel pressure now.

Bottom line...in order to run the FMU setup more reliably, you'd need to run bigger injectors and a smaller calibrated FMU. And of course running an SAFC to help trim and fine tune the fuel would be very helpful.

Oh BTW....Get Hondata soon!! If you really want something more reliable.


Khoi

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tad &raquo;</TD></TR><TR><TD CLASS="quote">they both are unreliable,
but i'd rather run a 10:1
people run pig rich with 12:1's

just my opinion tho</TD></TR></TABLE>

10:1 is richer than 12:1

 

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

10:1 is richer than 12:1</TD></TR></TABLE>

10:1 is Leaner than 12:1 i dunno what your talkin about.

the ratio is

(Increase in fuel pressure) : (Per poind of boost)

10:1 would be 10 psi of fuel pressure increase to every psi that is detected by the fmu.

12:1 would be 12 psi of fuel pressure for every psi of boost detected.

someone correct me if im wrong..

 

Why would 10:1 be richer?

10:1 = 10 psi fuel pressure per 1 psi manifold pressure.
12:1 is more pressure and more pressure is more fuel.

 

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

10:1 is richer than 12:1</TD></TR></TABLE>

dont think so.....were not talking about a/f, were talking about the rate at which the FMU rises the fuel pressure. 10:1 is 10psi of fuel for every pound of boost, and 12:1 is 12psi for every pound....so 12:1 is richer

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by donkiman &raquo;</TD></TR><TR><TD CLASS="quote">10:1 is richer than 12:1</TD></TR></TABLE>

UHmmm, no. the 10:1 thing means that for every psi of boost you make the fuel pressure goes up 10 psi.
Meaning:
10:1 fmu @ 9 psi = 90 psi over stock
12:1 fmu @ 9 psi = 108 psi over stock

The 108 psi over is going to pump more fuel through the injector than 90 will.

Bottom line......12:1 is richer.

::Edit::
Damn you Casey

 

I think donkiman is thinking A/F ratio and not Fuelpressure/boost ratio.

Khoi

 

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

10:1 is richer than 12:1</TD></TR></TABLE>

oh i get it now he was probably thinkin of air fuel ratio.. in THAT case you were right but they were not referring to a/f ratio , rather FMU discs.

 

ok so basically ill be straining the stock injectors on 12:1 fmu with 9 psi.

(my goal is hondata tuned around 1.2 bar boost so ok what injectors will i need for this hondata setup will 770cc do?)

now then at the moment i dont have enough for the hondadta but if i bought the 770cc injectors will i be able to use them with 12:1 fmu at 9 psi with walbro 255?
thanks for all your reples

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by f1 vtec &raquo;</TD></TR><TR><TD CLASS="quote">ok so basically ill be straining the stock injectors on 12:1 fmu with 9 psi.

(my goal is hondata tuned around 1.2 bar boost so ok what injectors will i need for this hondata setup will 770cc do?)

now then at the moment i dont have enough for the hondadta but if i bought the 770cc injectors will i be able to use them with 12:1 fmu at 9 psi with walbro 255?
thanks for all your reples
</TD></TR></TABLE>

No you cannot use the 12:1 FMU with 770cc injectors..you'll run pig *** rich then..Actually I doubt your car would even start..lol When you run bigger injectors..you need an SAFC to tune them down a little bit at Idle. Just keep the stock injectors in there, run the 12:1 FMU and keep it at 5psi. And when your ready, upgrade to hondata and get that bish tuned!!!

Khoi

 

yeah another thing,
you really dont want to run an FMU without an upgraded fuel pump(intank preferably)

the fmu puts alot of stress on the fuel system,
and the stock pump probly wont be able to handle it.

 

i think im better just going for hondata instead, i dont wanna end up damaging ringlands etc just cause of an fmu

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by f1 vtec &raquo;</TD></TR><TR><TD CLASS="quote">i think im better just going for hondata instead, i dont wanna end up damaging ringlands etc just cause of an fmu</TD></TR></TABLE>

yep, i've known ppl making really good power with fmu..

its cool if you dont mind swapping motors every few months

 

if you get something such as an e-manage or greddy blue box is that a lot better than an fmu?, i know the greddy e-manage is programmable but what if i only lan on running aorun 8 psi would the blue box be sufficient till igetmy aem ems?(currently poor)