The Vortech SFMU is a rising rate fuel pressure regulator that adds fuel pressure linearly based on boost pressure. The amount of fuel pressure that you will need the sfmu to add for each pound boost depends on the size of your injectors
Common SFMU Questions Asked and Answered
What size are the blue fittings that come on the SFMU?
They are -6an fittings
What size is the test port on the fuel rail?
-4an, you will need a female -4an end fitting to attach your new fuel line to the fuel rail. For part numbers see SFMU Installation Diagram
I've heard I should run a -6an return line with larger injectors is this true?
It's not necessary but is recommended. When running larger injectors, you will need to lower your fuel pressure at idle. Many people cannot get their idle fuel pressure below 28-30psi. For reference, with 30# injectors the desired idle fuel pressure is approximately 20-22psi
If I opt for a -6an return line will I also need to use -6an line from the fuel rail to the side port on the sfmu?
No. However you will need a fitting to adapt the -4an line to the sfmu. The part number of the adapter fittings available from Vortech Engineering is listed on the diagram posted above.
How much fuel line will I need?
You will need approximately 10ft from the bottom port on the sfmu to the back by the tank. This should be enough whether you mount your sfmu on the passenger side of the firewall or the driver side. From the passenger side you will need approximately 9ft.
You will need an additional 2-5 ft to go from the port on your fuel rail to the side port on the sfmu depending on where you are going to mount your sfmu.
Can I just get one 15ft piece of fuel line instead of buying separate lengths?
Yes, but I recommend spending the few extra dollars for individual sized pieces. The ends come wrapped and the braid is tight. The less cutting you have to do of this stuff the better. Not only will it be easier to install the fittings on the fuel lines, but you will probably save yourself some cut up hands and definetly some aggravation.
Are there other companies that make ss braided fuel lines besides Aeroquip
Yes, just check the pressure rating before purchase. Aeroquip is rated at between 750-1000psi. Other's are rated as low as 50-100psi which you don't want to use especially if you are on stock injectors where you will be running fuel pressures above 100psi when boosting.
What part numbers from the diagram should I replace if I want to use a -6an return line
You will replace 1 of the 5 -4an female end fittings with a -6an female end fitting, part number -
For the fuel line you will need:
one 10ft -6an line, part number -
one 3ft -4an (6ft if mounting on the driver side of the fuel rail) line, part number -
AER-FCA0406 for 6ft.)
Do I need any fittings to install the line back on the tank?
No, all you need are some hose clamps. One for the -4an line should be fine, it fits quite snugly and was actually a bit of a pain in the ass to get on. You may need to use a little oil to lube it up. The -6an line on the other hand is a bit loose gitting, so you may want to use two small hose clamps just to make sure it's not going to go anywhere
What disc ring combo should I use for my sfmu?
First check this thread: SFMU tuning and injectors
If you don't find it there, search there are plenty of threads on sfmu setups. After searching and reading for an hour then ask if you still can't find your answer and people will be more helpful
If you're confused with all the fitting sizes and are about to give up on doing this yourself, don't worry and just order the part numbers given here and on the installation diagram and you will be set to go.
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