ARB CKMTP12 High Performance Twin air kit

[RoyJ]

I guess that's just the "one is none & 2 is 1" coming out in me. I like to have options. Always be prepared is my moto. I guess the US Army did that to me. Anyways, we plan to get off the beaten path, & we are both pushing 60. I do not want to be stranded on the side of ANY road or in the middle of BFE. Redundancy is good---up to a point. I have the space & weight is NOT an issue with my truck. I carry an ARB plug kit as well & figure if i have a good compressor, why not have an impact as well.

Where are you getting the "real CFM @ 90 psi" from ? I have been reading 6+.

Makes sense then. I'd look for an efficient 3/8" drive, that uses relatively low CFM. If you operate an efficient 3/8" at full power, it may be similar to an inefficient 1/2" at partial power, but you have the benefit of a smaller wrench.

Real CFMs are very difficult to find, so I do my estimates based on real tire test, and in comparison to 120 volt compressors, which seem to be tested with much higher consistency. Single stage compressors are very similar in adiabatic efficiency, so if a 15 amp, 120V compressor is 5 CFM, then how can a 54 amp 12V (5.4a 120V equivalent) produce the 3.0 CFM that ARB advertises?

I'm using Romer's test to estimate ARB's CFM, based on Puma's 1.34 CFM rating. I believe Puma's rating because it's much closer to a 120V compressor based on power consumption (40A/12V, or 4.0A/120V):

http://www.expeditionportal.com/forum/archive/index.php/t-135582.html

I did make a math error though, doing it again gives roughly 2.18 CFM for the ARB, which is very good.

138 seconds for Puma, 85 seconds for ARB (with tank). So, 138/85 x 1.34 CFM = 2.18 CFM

In comparison, the well respected ExtremeAire Magnum does 2.6 CFM @ 100 psi, and draws 82 amps. The ARB draws 63A at 90 psi (on ARB's graphs). If we go by their claim of 3.0 CFM, then either the Magnum is super inefficient (doubt it), or ARB is blowing smoke. But if we assume 2.18 the the power to CFM ratios would be very similar.

 

[RoyJ]

If the ARB is only sporting 1.8 real cfm @ 90 psi, then what is the difference (cfm wise) between that & this ??? http://www.sears.com/craftsman-3-ga...gclid=CKaRutfhw8sCFYI9gQodS-gL1A&gclsrc=aw.ds Other than the smaller size & portability & that it is 12v.

I already have one of these & yes, my inverter will start & run it---even when it is below freezing out (I have already tried it).

It depends how much you value weight and space. The 120V compressor + inverter may end up weight 3x more and takes 3x more space than the ARB. Also, be careful operating an oil lubricated pump on an angle, it doesn't take much to starve the oil splasher and seize the piston...

I was also going to mentioned power efficiency, thinking inverting DC to AC is less efficient. But then remembered in my winch study thread, DC motor efficiency decline with increasing amps whereas induction motors are fairly constant. So may be a wash in the end, especially if you operate at higher PSI (higher amp).

 

[Ducky's Dad]

138 seconds for Puma, 85 seconds for ARB (with tank). So, 138/85 x 1.34 CFM = 2.18 CFM

That math only works if the the Puma has a tank the same size as the ARB, no?

 

[TwinStick]

All this talk is way over my high school diploma head, that's for sure. I just don't want to waste $800+ & end up with nothing better than i have now. Space is of concern more than the weight as far as traveling with the truck & camper. Portability is also a HUGE selling point for me. Not all trips will be with the truck & camper, some truck alone, others with the car. I don't really care which is more efficient, I just want something that works for me & works well, especially for $800+.

I know it is not real efficient to convert 12v to 120v, but I have a 270 amp alternator on the truck already & also a couple different inverters. Big batteries take up more space & cost good money as well. A 700 watt & a 2000/4000 that will be hard wired to the dual batteries via 2/0 Ga welding cable & soldered lugs.

Keep the input coming though, I love to learn about this stuff. Thanks

 

[Ducky's Dad]

I just want something that works for me & works well

Then you need to look at the Viair 300P. It's $150 now at Summit with free shipping and no tax; portable; comes in a kit bag with coiled hose, gauge, inflator; and puts out 2.4cfm at 90psi. You can use it with your 5-gallon tank or hard-mount it later if you want. It will fit behind the grill of your 3G, and you will always know where it is, no need to dig it out of the tool box. Cheap enough to buy two to satisfy your redundancy fetish. Speaking of which, I still carry my 300P in the PW, even though I have a Warn 12cfm hard-mounted. Downside is that it is 33% duty cycle vs 100% for the ARB.

http://www.summitracing.com/parts/var-30033

 

[TwinStick]

I fear that hard mounting to my truck, it will get destroyed by the NY State winters & salt that goes with em. Can't spray it with Fluid film either to protect it, that would cause it overheat in no time, plus, it is flammable. It also says "mot recommended in sub zero conditions" ???

I think more research is in order. Maybe i could make my own system & mount it in a rugged box ?

 

[TwinStick]

http://www.summitracing.com/parts/var-45053

Is this one a LOT better then the one you posted ? I am liking the 100% duty cycle vs the 33%. What exactly does that mean anyways ? It can run indefinitely----or does it mean 30 min on/30 min off ? Or something like that ?

Thanks

Edit: http://www.viaircorp.com/tech.html Found it.

 

[Ducky's Dad]

http://www.summitracing.com/parts/var-45053

Is this one a LOT better then the one you posted ? I am liking the 100% duty cycle vs the 33%.

I think the answer is a definite yes, and no. There may be some inconsistencies/errors between the Summit-posted specs and the Viair site specs. The 450P-RV is listed as 100% duty cycle, but their text says you can run it for 40 minutes straight. 100% duty cycle usually means you can run it continuously. !00% duty cycle on the ARB means that you can run it until it overheats and shuts itself down. Viair says

Thermal overload protection to protect compressor in event of
overheating/over duty cycle operation (where applicable)

, so it should shut itself down just like an ARB. Another possible inconsistency is between Summit's cfm specs and Viair's cfm specs, but I'd trust Viair's, especially if a phone call confirms them. The caution about sub-zero operation applies only to the supplied coiled nylon air hose. The compressors themselves are rated for

- Maximum operating temperature of 158° F
- Minimum operating temperature of -40° F

For my big Warn compressor, I just ordered a coiled polyurethane hose that I can leave on the compressor all the time, and I carry a 25' loop of poly hose in back so that I can reach anything I'm likely to need. My coiled nylon hose on the Viair is about ten years old and is still fine, but it's kept in the bag and has not been used in sub-freezing conditions (it may hit 90F here today). Re the salt and road crud issue, if you mount it behind the grill you can just have a local upholstery shop make a cordura cover with a couple of velcro straps to protect it. Easy on/easy off, and you can get waterproof cordura if you really want to protect it. I have had my Warn behind the grill for maybe six years with no cover and it's fine. The PW has no problem with overheating with the compressor mounted there. Mine has spent lots of time at low speeds in AZ in temps over 120F, never runs hot.

 

[RoyJ]

That math only works if the the Puma has a tank the same size as the ARB, no?

For sure, but then we'd have to take into account the different pressure cutoffs of the two compressors (120ish for Puma, and 150ish for ARB), and then look at how the compressors perform at those elevated pressures...

So I tried to keep things relatively simple and assume a 1.5g tank @ 120 is similar to a 1.0g tank at 150, and once the reservoirs are drained, both compressors are working against similar 20 - 60 psi head pressure (on a PW tire).


Speaking of the Puma, Twinstick, any reason you're not looking into it?

It's 100% duty cycle, and Cruisrphil has verified it by running 4+ hrs continuously. Very few compressors beat it in real life tests (ARB twin, ExtremeAire, Air Zenith OB2, and obviously the Oasis). You also have the benefit of an all in one package, with built-in pressure switch.

If you want to later integrate into an OBA setup, you just add a tank and some lines onto your truck, and that's it (pressure cut-in cut-out entirely done by built-in switch).

 

[RoyJ]

Then you need to look at the Viair 300P. It's $150 now at Summit with free shipping and no tax; portable; comes in a kit bag with coiled hose, gauge, inflator; and puts out 2.4cfm at 90psi. You can use it with your 5-gallon tank or hard-mount it later if you want. It will fit behind the grill of your 3G, and you will always know where it is, no need to dig it out of the tool box. Cheap enough to buy two to satisfy your redundancy fetish. Speaking of which, I still carry my 300P in the PW, even though I have a Warn 12cfm hard-mounted. Downside is that it is 33% duty cycle vs 100% for the ARB.

http://www.summitracing.com/parts/var-30033

I find Summit's specs to be real misleading.

If we look at Viair's site (under performance data):

http://www.summitracing.com/int/parts/var-30033/overview/

The compressor does 2.4 CFM @ 0psi. At 90 psi it drops to 0.92 CFM.

The best portable Viair offers is the 440P, it does 1.44 CFM @ 90 psi @ 44amp. This is roughly in line with Puma's 1.34 @ 90psi @ 40amp rating.

 

[Ducky's Dad]

I find Summit's specs to be real misleading.

Yep, that's why I pointed out the inconsistency. Summit says 2.4 at 90, so it looks like someone at Summit has a comprehension problem. But for $150, it's a good little compressor. If I had my druthers, I'd be running an Oasis, but I just couldn't quite fit one into the available space. My Warn at 12cfm free air flow and 100% duty cycle is surprisingly good, too bad it's discontinued.

 

[RoyJ]

Yep, that's why I pointed out the inconsistency. Summit says 2.4 at 90, so it looks like someone at Summit has a comprehension problem. But for $150, it's a good little compressor. If I had my druthers, I'd be running an Oasis, but I just couldn't quite fit one into the available space. My Warn at 12cfm free air flow and 100% duty cycle is surprisingly good, too bad it's discontinued.

Which model is that again?

It's too bad the Warns compressors were discontinued - bad economy perhaps? I remember the monstrous VTC that out flowed even the mighty Oasis at 0 psi, 20 CFM! The only high-power compressor they make today is the Powerplant winch, which I believe also free flows 12 cfm.

 

[Ducky's Dad]

Warn Powerplant HP from their website:

Max air pressure: 100 PSI, CFM rating: 12 CFM @ 0 PSI, 5 CFM @ 90 PSI. Onboard features include: integrated intercooler, pressure switch, thermal protection shutoff switch and air hose quick disconnect

Compressor specs look like mine, which I think was designated SPI. The SPI was the single cylinder version and the VTC was the twin cylinder with about twice the performance. No way I could fit the VTC between the grill and the radiator on my 3G Dodge. The Oasis was closer, but still would not quite fit. The SPI fits nicely and delivers all the air I really need. But more is always better. I think it was the economy that killed these big compressors. They were fairly expensive compared to things like Puma and Viair, and they hit the market at the wrong time. I got mine as a closeout and wish I had bought two. The "integrated intercooler" actually functions as a small air tank built into the compressor.

 

[Ducky's Dad]

Warn's press release from mid-November of 2007, just weeks before the fecal matter began to hit the recession wind generator.

Air-Power VTC - The Ultimate 12V On-Board Air Compressor
The VTC is the most powerful compressor in the Air-Power lineup. It has a high-horsepower fan cooled motor that drives the V-twin compressor. A large one-gallon air reservoir/intercooler not only stores compressed air, but cools it to prolong hose life. All this adds up to an amazing airflow rating of 20 CFM @ 0 PSI and 8 CFM @ 90 PSI, and the ability to air up a 5 gallon tank to 100 PSI in only 50 seconds!

The VTC showcases a number of outstanding features including a 100% duty cycle, and an air pressure switch that automatically shuts the motor off when it reaches its maximum pressure of 100 PSI and turns back on when more air is needed.

From powering air tools and rapidly inflating tires, to inflating large rafts and operating air suspension systems for on- and off-road vehicles - the VTC is an on-board air powerhouse.

Air-Power SPI - Big Power, Compact Size
For those looking for big power in a not-so-big package, the Air-Power SPI is a must-have. This workhorse comes with a strong fan-cooled motor and a 1/3-gallon air reservoir/intercooler for storing air and cooler air temperatures for extended air hose life. The SPI produces high airflow ratings of 12 CFM @ 0 PSI and 4 CFM @ 90 PSI, and will fill a 5 gallon tank to 100 PSI in just 90 seconds. Best of all, the SPI is compact enough to be mounted just about anywhere. Like the larger VTC model, the SPI also has a 100% duty cycle and an air pressure switch that shuts the unit off at its maximum air pressure of 100 PSI and turns it back on when more air is required.

 

[TwinStick]

RoyJ-

"Speaking of the Puma, Twinstick, any reason you're not looking into it?"

Which Puma are you referring to ? Link ?