BOSS PX07 vs VIAIR 444C: Which On-Board Air Compressor Do You Need?

If you're adding on-board air to an air bag or air ride system, two names come up again and again: the VIAIR 444C and the BOSS PX07. Both are 12V compressors built for air suspension, but they're made for slightly different jobs. This guide compares them spec by spec, so you can choose the one that suits your system.

We sell BOSS, so we've kept this to published numbers: BOSS figures from our product pages, and VIAIR figures from VIAIR's own product page for the 444C-EF, the version of the 444C whose full specs VIAIR lists there.

The quick answer

  • If you need a compressor that can run continuously, fill a large tank quickly, or support a full air ride setup, look closely at the PX07's 100% duty cycle and roughly 3.5 CFM of free flow.
  • If you're topping up a two-bag load assist kit and want something smaller, compare the 444C with BOSS's own compact options, the PX01 and PX02.

Spec comparison

Spec BOSS PX07 (12V) VIAIR 444C-EF
Motor 3/4 HP Not listed on VIAIR's product page
Free flow 100 L/min (about 3.5 CFM) 2.24 CFM
Duty cycle 100% at 150 PSI 100% at 100 PSI; 50% at 200 PSI
Recommended working pressure 0–150 PSI Not listed separately
Maximum pressure 200 PSI 200 PSI maximum working pressure
Max current draw 31.5 A (40 A fuse) 27 A
Outlet port 3/8″ NPT ported head Not listed on VIAIR's product page
Weight About 15.9 lb (7.2 kg) 10.85 lb
Dimensions 13.2″ × 8.9″ × 5.7″ (335 × 225 × 145 mm) 11.4″ × 4.1″ × 6.8″
Oil-free Yes Not listed on VIAIR's product page
Rebuildable Yes, with the PX07 rebuild kit Not listed on VIAIR's product page
24V version Yes, the 24V PX07 Not listed on VIAIR's product page

Duty cycle: the number that matters most

Duty cycle is how long a compressor can run, as a share of a set period, before it needs to cool down. A compressor with a 50% duty cycle can run for half the time and must rest for the other half. Run it longer and heat builds up, which shortens its life.

For a two-bag load assist kit, a lower duty cycle is fine. You run the compressor for a short burst to add a few psi, and then it rests. Fill a tank, run a full air ride system or use air tools, and the compressor may run for long stretches. That's where a 100% duty cycle compressor like the PX07 earns its place: it's rated to keep running at 150 PSI.

VIAIR lists the 444C-EF at a 100% duty cycle at 100 PSI, dropping to 50% at 200 PSI. The PX07 is rated 100% at 150 PSI. Duty cycle figures are only comparable at the same pressure, so check which pressure your system actually runs at.

Airflow: how fast you fill

Free flow, quoted in CFM or L/min, tells you how much air the compressor moves at zero pressure. Real-world flow drops as pressure rises, but free flow is still a useful way to compare. The PX07 lists about 3.5 CFM (100 L/min), and VIAIR lists the 444C-EF at 2.24 CFM. A higher number fills tanks and bags faster, which matters most when you're adjusting a full air ride system or recharging a 3–5 gallon tank.

Power draw and wiring

A bigger compressor draws more current. The PX07 pulls up to 31.5 A and needs a 40 A fuse and a check valve. Plan your wiring, relay and fuse before you buy. VIAIR lists the 444C-EF at 27 A maximum draw. Check the figure for the exact version you're buying, and make sure your alternator and wiring can handle whichever you choose.

Size and mounting

The PX07 measures 13.2″ × 8.9″ × 5.7″ and weighs about 15.9 lb, so it needs a solid mounting spot with airflow, such as on a frame rail, in a toolbox or under a bed. Measure your space before you order either compressor.

Complete kit or bare compressor?

A bare compressor is just the pump. To run it on a vehicle you also need a pressure switch, which tells the compressor when to start and stop, a relay or solenoid to carry the current, a fuse, and a check valve to stop air flowing back into the head.

The PX07 complete kit includes a 110–135 PSI pressure switch, a 100% duty solenoid, a check valve, a 3/8″ flare fitting and a braided hose, so most of the control side is in the box. You'll still need to fit a 40 A fuse. If you buy a bare PX07, budget for a pressure switch in the range that suits your tank, and a check valve.

VIAIR sells the 444C in more than one package, so check what's in the box for the version you're looking at. A cheaper bare compressor can end up costing more once you add the parts it needs.

Which should you choose?

Choose the BOSS PX07 if:

  • You run full air ride, or bags plus an air tank
  • You want a compressor that can run continuously at working pressure
  • You want the option to rebuild it rather than replace it
  • Your vehicle runs 24V (the PX07 comes in 24V too)

Consider a smaller compressor if:

  • You only top up a two-bag load assist kit now and then
  • Space and power draw are tight

For the smaller job, BOSS's PX02 delivers 1.5 CFM with a 50% duty cycle, and the PX01 weighs just 4.2 lb. Both are worth comparing against the 444C on price and spec.

Pair it with a tank

Whichever compressor you choose, an aluminum air tank makes the system faster to use. The compressor refills the tank in the background, and the bags fill from stored air in seconds.

Have questions about wiring or sizing? Contact us. We're in St. Louis and answer calls 8am–4pm CST, Monday to Friday.

Sources

Checked 30 Oct 2026. Specs can change, so confirm against the manufacturer before you buy.

VIAIR and 444C are trademarks of their respective owner. They are used here only to identify the products being compared. Their owner is not affiliated with, and does not sponsor or endorse, Arch Country Auto or BOSS.

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