Build your own adjustable fuel pressure regulator ;)

[oldeskewltoy]

I decided to make a guide as to how to build your own adjustable fuel pressure regulator. The TOM'S unit is over $300 on ebaY, and most of the other types require moving the regulator mount off the fuel rail and onto the firewall. B&M has been selling a kit for over 10 years that, although specified for use on Hondas, works perfectly well on our FPR too.

Here is the product: B&M 46058 is the part number. The cost is between $35 and $55... (far cry from $300 )



Because it is being used on a Toyota, there is a need to make one of 2 modifications. 1) add a 2mm thick rubber seal shaped to the same size as the original seal (shown below) OR have the upper housing machined down 1.5-2.0mm (actually machined "up" in this case)

You begin with any of the 4AGE FPRs, this will work on a 20V FPR as easy as it does on the 16V.



Here is a 16V fpr, mounted on a rail. First you remove the 2 bolts, and gently twist the fpr to ease removal. Remove the fpr, put the rail aside.


Using a Dremel, or other cutter, cut all the way around the edge of the FRP. Not too deep, about .5mm-1mm depth is deep enough.


Once you have cut 3/4 of the way around, the spring inside will be "pushing" on the lid of the FPR.

Note the thin gasket inside I referenced above.

The key dimension is the overall diameter of the fpr, and the machined inner diameter of the B&M fuel pressure modifier. These are PERFECT.

The only problem is as suggected above, the base of the Toyota FPR is not thick enough to be tightened in place with just the flange that is part of the assembly. You can kind of see the assembly disappear inside the B&M housing. As I alluded too @ the beginning, you can have the bell part machined down about 1.5mm, or you can replace the wafer thing gasket with a much thicker one. In either case the cost to do the mod is at maximum $20(to pay someone to machine the housing)

The Toyota spring is longer than the one in the kit, I retained its use for now, *IF* I find the original spring is too tight, I'll disassemble the unit and install the spring that came with the kit. The reason I retained the original spring is the height inside the red chamber is actually taller, and the smaller spring applied nearly no pressure when I first installed it. As I alluded too, I'll hold on to it for now and if the std spring is too tight without adjustment, I'll move to the spring that came with the kit.


Well, here is the unit assembled, and remounted on the fuel rail.


the vacuum connection is at the top of the adjuster