FMU on nsport kit

[:: orion ::]

What's the ratio on the FMU?

Basically, for every pound of boost, the FMU adds X amount of fuel pressure...i.e. a 10:1 FMU will add 10psi to the rail for every pound of boost.

Factory pressure is 43psi at WOT (or 0 vacuum), so add 10psi per pound of boost, and it adds up quick.

No way would I ever run more than 100psi in my fuel rail...

Hell, 65psi killed a "Walbro 255 High Pressure" pump in less than a year according to a guy over on Freshalloy - He posted today asking why his Walbro was dead.

Later - Brian

[TurboKA37]

is 10:1 a realistic ratio for a FMU? cause at 65 psi on the fuel system would mean ur only adding a little over 2 psi of boost. I am assuming 10:1 was just for ease of calculations and if it was then what is a realistic ratio for a FMU?

[:: orion ::]

The N-Sport kit comes with a 7:1 FMU...

So 7psi (the n-sport setting) seems to be about the most I'd EVER want to run with an FMU soley for the purposes of being able to sustain the fuel pressure needed.

43psi + 49 from the FMU @ 7psi = 92psi in the lines...I thnk that's pretty high.

And a Walbro 255 HP should be able to keep up, but...

Later - Brian

[WDRacing]

I wouldn't use an FMU for anything over 8 psi. Even with a big FMIC. I just don't trust them. Plus your running your injectors pretty damn hot, could have one lock up on you. Fortunatly they usually lock open. There are to many ways of adding fuel nowadays to rely soley on a FMU.

WD

[MainEvent212]

why not just use an FMU? it sounds like it should work pretty well given you have a good fuel pump, large enough injectors and a fuel rail that can take the pressure...

[:: orion ::]

The point is to get an FMU so you don't have to upgrade to bigger injectors...

But I agree - I am considering one for my setup to run a little more someday (maybe...I don't think I need any more, but we'll see).

Later - Brian

[MarkEmark]

Orion or WD...I'm going to be turbocharging my car soon, at 7 psi with a large FMIC, a 10:1 vortech FMU, and of course, 94 octane...How essential would you say it is to get a better fuel pump, like the Walbro? Do the NSport/XS/Fmax's use better fuel pumps?!!!!!?Sorry for the slight thread-hijacking :icesangel

[TurboKA37]

i think the only one of those kits that comes with a pump is the nsport kit which comes with a "Walbro in-tank replacement high-flow fuel pump" i suppose the 255. and i was watching "trucks" on the new tnn today and they were showing how the fuel injection on a deisel engine works and they said the fuel lines on a deisel engine handle up to 23,000 psi or sum crazy number like that!! wish we could get some of that in our 240's so we could run FMUs at any psi the engine could handle!

[:: orion ::]

With an FMU you HAVE to upgrade the pump...

Stock pump was not designed to flow (43 + 70 = ) 113psi of pressure.

I'd NEVER run an FMU with an OEM pump, although the S14 pump is decent. But not good enough to supply that kind of pressure reliably...

As I said in some other thread - DO NOT RUN AN FMU WITHOUT AN UPGRADED PUMP.

Later - Brian