06-17-2015, 06:11 PM
This is something I have been web-wheeling/obsessing about for the last month or so. I have a Jeep so real estate to mount a compressor is tight leaving my options further limited. In my research it seems that there are two main types of systems, portable and OBA (On Board Air). Lockers and air horns pretty much force you to go with an OBA system but they don't use that much air so a small compressor would function fine for those alone. Ignoring the air tools for now, your biggest driving factor is tire size. 37" tires are huge and take a ton of air to fill. Even a modest compressor setup will be a few minutes a tire to fill.
Well there are a few things to consider when looking at a compressor or OBA system. First, any air tank volume you plan to install is insignificant and can be ignored. Air tanks are really only for the air horns. A 2.5 gallon tank isn't enough to air up more than 1 tire so the compressor flow rate is what you should focus on. Second, the tire size is the biggest hurdle to fast refill times. Third, how patient are you when airing back up. Fourth, cfm numbers are misleading/meaningless without a @ _ psi to go with them. Fifth, dont always trust cfm and hp numbers. There is no possible way the PUMA compressor can do the 3.4cfm @40psi when only using 360watts per the EBAY ad, sorry this is just physics. The 360watts does match the ~2 cfm rate on the manufactures website and matches the calculated ~.4-.5hp required to do ~2cfm @40psi. Typical commercial/industrial compressor system efficiency is just below 60% in perfect condition so don't expect a mass produced consumer unit to meet or hold that efficiency.
So realistically, what are your choices? (note that this is not an exhaustive list, just most of what I have seen in the industry)
Super Fast Options
-Power Tank or Similar CO2 system. Pros - Portable system, fastest possible tire fill times, can run ail tools. Cons - Needs to be refilled, bulky, not typically used for lockers (but possible).
-York Compressor, engine driven pump. Pros - ~8cfm is faster than most home/shop compressors, mounts under hood, super reliable, runs air tools all day long, can be built from junkyard parts to save $. Cons - Cost typically over a grand for the nice kits (Kilby), engine must be running, crowded engine compartment or loss of AC on smaller vehicles.
-Oasis Air, york type compressor driven by a big electric motor (used in hummer Central Tire Inflation Systems, think 5hp winch motor). Pros - Fast ~8cfm, reliable, run air tools. Cons - Bulky, heavy, needs lots of electrical power (iffy for single battery setups), ~$1500 price tag.
Fast Options
-Viair Twin compressor kits. Pros - Always have a backup compressor, decent flow rates, many options and price points, kits include all small parts. Cons - Costs generally north of $500, need adequate space.
-Other twin compressor systems, generally from lowriders. Pros - Potential cost savings from Viair systems. Cons - Needs fabbing and many small parts.
Ok Options
-Air Zenith OB2. Pros - ~4cfm at tire air-up pressures, has fan to prevent overheating, water and dust proof, 100% duty cycle, limited use in offroading but proven in lowrider circles. Cons - No install kit so needs fabbing, ~$400
-Outback ExtremeAire Magnum. Pros - ~4.5cfm at tire air-up pressures, 100% duty cycle. Cons - No install kit, ~$550-600.
-ARB CKMT. Pros - ~4.65cfm at tire air-up pressures, 100% duty cycle, small size, pre-assembled with pressure switch, comes with complete wireing and switching harness with provisions for air lockers. Cons - No mounting bracket, $30 extra for the ARB basic hose kit, $550msrp.
Adequate but Slow Options
-Viair Constant Duty kit. Pros - 100% duty cycle, reasonably priced complete OBA system ~$350. Cons - Slow 1.3cfm at tire fill pressures
-PUMA 1006D compressor. Pros - Complete compressor and tank option for easy mounting with space, Cheap ~$120-150 on ebay, decent speed ~2cfm at tire fill speeds. Cons - Cheap, typically dont last long when not mounted inside the vehicle
Other options
These other options were part of my research but not really worth looking into given the 37"+ tire size. These will take 5+ minutes a tire and likely overheat before completing the job. Many cheap compressor dont have overheat protection to expect limited life.
-Smaller Viair OBA kits, will typically his the 33% duty cycle limit prior to having everything full.
-Superflow MV52, portable and cheap $50-70 but dont last long and will begin to overheat as it wears.
-ARB single compressor CKAT, will be over worked filling 37s.
-Harbor Freight type cheapo compressor. Dont waste your time, yes you can afford to replace it once a year when it dies, but it's slow and will die at the worst time.
Most people have their favorites or reasons to stay away from a specific company but with the recession, anyone still on the market is there for a reason. I am still on the fence as to what I want to do but given space and financial constraints I can say I am looking in the "OK" category or starting with the Viair constant duty and upgrading the compressor in the future. But f I had the funds today I would do a york kit.
Last edited by
kolof; 02-02-2016, 02:44 PM. Reason: Corrections
Any thoughts on my more recent quandaries, Buick?
