Dont Know the author but good reading
"Grainger valve" is just a nick-name for a simple ball &
spring check valve with adjustable spring tension. McMaster-Carr sells
them as part number: 48935K25
You can follow the diagram below to have the quick spool up, *ONLY* when you floor it. Sometimes "lazy" driving is required, and you don't want quick spool up. A wide-open-throttle switch is even better than a toggle switch; you only go to high boost when you floor it. It makes the "drivability" of the car excellent! Try it; you'll like it! The Grainger valve controls the high boost setting, while the "low" setting is permanently at minimum boost, which is usually about 7 psi.
Please note that the unused vacuum barb on the solenoid valve is blocked off! I represented the block with a black rectangle. You must cap off this nipple. Again, there is a small (about .020") vent hole drilled into the output barb of the Grainger valve to act as a vent.
Because of several requests, below you will see a fully manual "high-low" boost setup with adjustable "high", and adjustable "low" settings. The bleed to adjust "low" acts as the vent. If you're gonna run around with the low setting closed a lot, then add a vent anyway! The Grainger valve controls the "high" setting.
Not all solenoids flow the same. Some flow much more than others.
Apply 12Vto one at a time, and blow through them with your mouth. Use
the ones that are easiest to blow through.
Here's how you make and adjust it:
Take it from here, and put it
THERE! Then screw on a brass barb fitting.(McMaster Carr part number) 5346K51
Drill a tiny hole (about .020") in a brass barb first... (90degree
brass barb is part # 44555k142)
Then bang the barb into the hole with a hammer. It should be in there really tight!
Then assemble the whole thing, and the finished product looks like
To adjust the valve, unlock the lock-nut, and screw the unit together, so that it gets shorter. The shorter you make it, the higher the boost goes. You should be able to get it really close to 14 lbs without hitting cut out. Re-lock the lock ring, and it'll stay where you set it.
The knurled knob turns to make the valve body shorter or longer. The lock ring stops the movement after adjustments are made. The vent orifice needs no filter, as it never sucks air in. Making the valve longer LOWERS boost, while making the valve shorter RAISES boost.
It has been noted that spiking seems to be minimal when the lines are kept short, and the vent hole is kept small. Try .020" - .022" for a vent hole.