Radium 3AN Vacuum Port Adapter for MPR, DMR, FST-R, FPD-XR

Radium Engineering 3AN Vacuum Port Adapter, Black - Part #14-0369

Every Radium fuel pressure regulator and pulse damper has a threaded vacuum port for the boost reference, and the barbed adapter that ships in the box is fine until you're running braided 3AN line to everything else in the bay. Radium's 14-0369 is the 10-32 to 3AN male adapter that lets you plumb that reference with a proper hose end instead of a push-on barb and a clamp.

What It Is and Why It Works

The vacuum port on Radium's MPR and DMR regulators, FST-R surge tanks, and FPD-XR pulse dampers is a #10-32 thread. This adapter threads into it and gives you a 3AN male flare on the other end, so a 3AN hose end seals the same way every other fitting on the car does. It's machined from steel and black zinc plated, which is the right call for a fitting that lives on a fuel component and gets a wrench on it; an aluminum one this small would strip. On a boosted K-series the regulator's reference line is what keeps fuel pressure rising 1:1 with manifold pressure, and a leaking or kinked reference is a lean condition you won't see until the log. A flared 3AN line doesn't pop off under boost and doesn't harden and crack the way rubber vacuum hose does next to a header.

Specs

Fitment

Radium products only. The 10-32 thread is not a common vacuum port size on other brands' regulators, so check before ordering for anything else.

What to Know Before You Buy

Radium recommends a medium-strength thread locker on the 10-32 thread (green Loctite 290 is their pick); the fitting is small, sees vibration, and has no jam nut. If you're running the regulator without a vacuum reference, in a static-pressure setup, you want Radium's 18-0112 port plug instead of this. And if the rest of the car is rubber vacuum line, the 3/16 barb adapter (14-0190) that came in the box already does the job; this fitting is for the build where everything is AN.