Tire inflator guide
VIAIR 400P EF Portable Compressor (40143)
Re-inflating large tires after airing down, from a 12 V battery with the engine running
A 12-volt portable compressor rated to 150 PSI with a 30 amp draw, powered from the battery through SAE-connected clamps while the engine runs. It comes with a 25-foot inflator and deflator hose, a 100 PSI inline gauge, inflation tips and a carry bag.
Listing checked . Confirm the model, included parts and availability before ordering.
Published specifications
- Maker: part 40143; 12 V permanent magnet motor; IP54
- Maker: 150 PSI max working pressure; 30 A max draw; 40 A fuse
- Maker: about 20 min continuous at 100 PSI, 1 h at 40 PSI (72F)
- Maker: 11.8 x 7.57 x 6.69 in; 10.35 lb net
- Maker: 25 ft hose; 100 PSI gauge, +/-3%; cord 6 ft (listing 8 ft)
- Maker: -40 to 158F ambient range; 73 dB at 0 PSI
Fit and limits
Strengths
- 150 PSI rating with automatic thermal overload protection
- 25-foot inflate and deflate hose for airing down and back up
- IP54 rating and an operating range down to -40F
Caveats
- Runs from battery clamps with the engine running, per the manual
- Supplied gauge reads only to 100 PSI
- Power cord length differs: 8 ft in listing, 6 ft from VIAIR
Which 400P this is
The listing is for the VIAIR 400P EF with the Enhanced Flow Portable variant selected. VIAIR's product page and user manual identify this compressor as part number 40143, the 400P Portable Compressor with Enhanced Flow Technology. VIAIR also sells an automatic version of the 400P EF under a separate product page, so check you are buying the one you want.
VIAIR describes the EF version as an updated 400P with an updated head for heat dissipation, an SAE power cord, and what it calls Enhanced Flow technology, claimed to give up to 10 percent faster fill and 20 percent more performance. Those two percentages are VIAIR's own claims.
The listing adds a 2.59 CFM free-flow figure and says the compressor suits tires up to 35 inches. Neither figure appears in the VIAIR text we read, although the product page has performance and fill-rate sections presented as graphics.
The specifications that matter
VIAIR lists a 12-volt permanent magnet motor, a maximum working pressure of 150 PSI, a maximum current draw of 30 amps and a 40 amp fuse. The ingress protection rating is IP54, and the product page gives an ambient operating range from minus 40 to 158 degrees Fahrenheit.
The product page lists dimensions of 11.8 by 7.57 by 6.69 inches and a net weight of 10.35 pounds. It gives an inrush current of 110 at 0 PSI and a sound level of 73 dB at 0 PSI.
The included inline pressure gauge reads to 100 PSI with a stated tolerance of plus or minus 3 percent in the manual. That means the gauge tops out below the compressor's 150 PSI maximum, which matters if you plan to fill anything above 100 PSI.
Duty cycle, stated two ways
VIAIR's product page expresses the duty cycle as 100 percent at 40 PSI and 33 percent at 100 PSI. The user manual expresses it as continuous use of approximately 1 hour at 40 PSI and approximately 20 minutes at 100 PSI, both at 72 degrees Fahrenheit.
The manual says operating beyond the maximum pressure or duty cycle will damage the compressor. It describes an automatic thermal overload protector that cuts power if the compressor overheats and resets once it cools, and it suggests letting the compressor cool for about 30 minutes before restarting after a shutoff.
The manual also warns that the compressor becomes very hot during and immediately after use, and asks that it be cooled down before it goes back in the carry bag. Its troubleshooting table points to poor ventilation or high ambient temperature when the thermal protector trips repeatedly.
Power: battery clamps with the engine running
This compressor draws up to 30 amps, and the manual's instructions power it from the vehicle battery through SAE-connected alligator clamps. The manual states that the engine must be running while the compressor is in use.
The listing and product page describe a two-pin SAE connection with a 40 amp inline fuse holder, compatible with VIAIR power adapters including its seven-way trailer plug connector, which the product page lists as a separate accessory. The manual says to use this compressor with 12-volt DC systems only.
The listing gives the power cord as 8 feet, while VIAIR's product page lists the power cord length as 6 feet. We are reporting both figures. The air hose is 25 feet in both sources, and it is a five-in-one inflator and deflator hose with the inline gauge.
In the box, and hose and chuck notes
VIAIR's box list is the compressor, SAE power connects, the coil hose, an inflation tips kit and a carry bag. Its features list adds a three-piece inflation tips kit with a Presta valve adapter, an I-beam sand tray and the carry bag. The listing describes the bag as dual-compartment.
The manual asks for heat-resistant extension hoses rated for at least 200 PSI working pressure, and warns that a close-ended tire chuck can cause excessive pressure buildup on a compressor without an air tank. It recommends an open-ended chuck such as the one on the supplied hose.
The supplied hose supports hands-free continuous deflation for airing down, according to the manual. Its safety precautions also cover driving on aired-down tires; read those in the manual before using the deflate function off-road.
Care and warranty
The manual says the motor is permanently lubricated and maintenance-free, and that you should never try to lubricate the compressor. It asks that dust and dirt be cleaned regularly from the cooling fins and motor housing, that the air filter be installed during use, and that repairs go to the manufacturer.
Its safety list says the compressor should never be left unattended during use, should not be used near flames or where aerosols are sprayed, and should pump only atmospheric air. Children should not operate it.
VIAIR's limited warranty in the manual covers defects for one year from the original purchase date, when properly installed and under normal use. Returns need a Return Goods Authorization number from VIAIR, and the warranty covers product defects only, not damage from misuse or abuse.
Check the current listing
Confirm the model, included parts and availability before ordering.
Primary sources
- VIAIR product page for the 400P EF Portable Compressor, part 40143
- VIAIR 400P Portable Compressor with Enhanced Flow Technology user manual, part 40143
Primary sources checked .
Compare with
- VIAIR 88P (00088) 12V Portable Air Compressor Kit
Airing up truck and off-road tires up to 33 inches
- DEWALT DCC020IB 20V MAX Corded/Cordless Air Inflator
20V MAX owners who want one pump for tires and air beds
- AstroAI CZK-3631 (AIRUN H) 12V Portable Tire Inflator
Topping up car, motorcycle and bike tires from a 12V socket
- ETENWOLF Vortex S6 Cordless Heavy-Duty Air Compressor
Truck, SUV and off-road tires away from any power outlet
- AstroAI AIRUN L7 Cordless Tire Inflator, 150 PSI
Car, motorcycle and bike top-ups away from a 12V socket
Side-by-side pages, this model next to: VIAIR 88P (00088) 12V Portable Air Compressor Kit, DEWALT DCC020IB 20V MAX Corded/Cordless Air Inflator, AstroAI CZK-3631 (AIRUN H) 12V Portable Tire Inflator, ETENWOLF Vortex S6 Cordless Heavy-Duty Air Compressor, AstroAI AIRUN L7 Cordless Tire Inflator, 150 PSI.