FMU Selection

[Wicked 3800 V6]

Aight, so I'll probably get an FMU. But which do I choose? As far as I know, I know how the cylindrical line-sensored FMU works -- one fuel line in, one out, and one manifold source. But I've seen Vortech, Powerdyne, Cartech, etc. versions of this from $50 to over $150 to more. I've also seen digital FMUs for $400+, but I'm not exactly keen on purchasing one of those and reinventing the wheel. Are there specific quality / performance issues with running a cheaper FMU (Vortech) than a more expensive one (Cartech)?
Thanks!
BTW, do these replace the stock FPR or piggyback?
-Rob

[xjarayax]

I'm running the Cartech on mine. It's piggyback.

[Wicked 3800 V6]

XJ what rate is yours? 10:1, 12:1 ... thanks.
Any tips on installation / fittings / hoses / etc? And is that all you have in terms of fuel management? You've been a great help for my install.
-Rob

[xjarayax]

What rate is it? The Cartech one's have an adjustable rate. And yes, that's all I have for now. At 7-8~ PSI I know it is going a bit lean, so I will be doing the Walbro upgrade soon.

Best way to handle the fittings is just wait until you get the FMU, splice into that line and see what works best. Personally, I used some brass barb plumbing fitting's from Home Depot with some clamps for mine. I cut and spliced into the line, not went right at the fuel rail. If you do that the connector part is pretty expensive from Vortech, although it would probably look a little cleaner.

This picture MAY help... but you might want to zoom in over the FMU... http://xjarayax.fbodyv6.com/images/turbo/DSCF0298.JPG

edit: spelling

[ September 01, 2003: Message edited by: xjarayax ]</p>

[DrFix2Fly]

I've chosen the Vortech Race bypass valve to go with the rest of my system. It came as a 12:1 but it is adjustable. Plumbing this thing in is a problem. I'd prefer to use all AN fittings with stainless lines, but the rail downstream of the stock regulator is -5 wich is a real bastard size. It dumps into the return line wich is -4. What we need to find is -5 lines and fittings to the FMU and -4 from the FMU to the return line. Flaring the lines is a problem because AN is 37deg whereas automotive is 45. When you get a Vortech, it will have 45deg fittings on it. Be careful, they will not mate properly.

[Riles]

I run the vortech standard fmu. I got screwed by somebody on ebay when I bought the super fmu, so I got another.

I run between 4:1 and 6:1... I still can't decide which one to go with. According to my powerdyne instructions, it says I want to be at 60-70 psi of fuel under full boost (6 psi), so this really works out to be 4:1, but I run a little on the rich side.