What's the fastest +12volt pump for airing tires up

[RoyJ]

Other things to note is the size difference. Notice how much larger the head is on the OB2. This tells a story. It's much more efficient at dissipating heat and which is why it can be 100% duty cycle at 200 PSI.

The rest of the story is told by the power consumption. Extreme Aire 82 amps draw @ 100 psi, 2.6 CFM vs. OB2 35 amps draw @ 100 PSI, 2.47 CFM

This is where we have to be careful in the absence of industry standardized testing procedures. As an engineer I can tell you one of the two companies isn't telling the truth, and I lean towards the OB2.

The adiabatic compression efficiency of piston compressors are very similar, given a similar design (reed valve teflon lubed), displacement, and rpm (both direct driven DC motor). It's extremely (no pun intended) unlikely one is 40% as efficient as the other.

My guess, either the OB2 doesn't put out those numbers, or the amp draw is higher than stated.

Why? Think about a 3450 rpm 120v home compressor. To achieve 2.47 CFM @ 100psi, it'll take a LOT more than a 3.5 amp motor (on 120V). Most compressors putting out those volumes are running around 7 to 9 amps (@120V), which not surprisingly, is close to the Extreme Aire's 82 Amp @ 12V.

 

[photo nomad]

The ARB twin is a good and fast compressor, plus if one of them fail, the other will continue to work. It's nice to have redundancy in a small package.


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[Crom]

This is where we have to be careful in the absence of industry standardized testing procedures. As an engineer I can tell you one of the two companies isn't telling the truth, and I lean towards the OB2.

The adiabatic compression efficiency of piston compressors are very similar, given a similar design (reed valve teflon lubed), displacement, and rpm (both direct driven DC motor). It's extremely (no pun intended) unlikely one is 40% as efficient as the other.

My guess, either the OB2 doesn't put out those numbers, or the amp draw is higher than stated.

Why? Think about a 3450 rpm 120v home compressor. To achieve 2.47 CFM @ 100psi, it'll take a LOT more than a 3.5 amp motor (on 120V). Most compressors putting out those volumes are running around 7 to 9 amps (@120V), which not surprisingly, is close to the Extreme Aire's 82 Amp @ 12V.

I've been doing a ton of research on this. Allow me to share what I've found. But bottom line first, I do agree. My hypothesis is that Air Zenith may have fudged their CFM numbers, or they had a bad meter when they took their readings.

The reason I say this is when I compare the time that the Viair 444C Dual Value Pack takes to fill a 5-Gallon tank (5:30), to the Air Zenith OB2, it's only 16 second behind. Air Zenith quotes a time of 5:14.

I've seen videos of the OB2 filling a 5-gallon tank in about 5 minutes, so I believe that number is real.

The Viair 444C quotes a Max. Amp Draw: 40 Amps. And compared to the Air-Zenith which quotes Max. Amp Draw: 35A. They are close. The CFM numbers quoted by Viair are smaller though.

But looking back at the Extreme Aire's Magnum compressor, that thing has a much larger motor at 1.5 horse power vs. the 3/4 HP of the OB2. I was also wrong in this area, the Magnum is 3.5" longer than the OB2. No question that the magnum is going to be stronger, but at the same time I can't ignore the smaller head size, and my assumption of smaller displacement. I did manage to find pictures of the piston and ring in the OB2, and it's huge. Therefore I don't think the displacements are similar between the two which may explain how a smaller sized motor with larger piston / ring do more with less HP.


What would be great to know is how fast can the magnum fill a 5-gallon air tank to 200PSI? That would be really good to know
!

If I do get my hands on the OB2 I will meter amp draw and report back.

View attachment 304756
The ARB twin is a good and fast compressor, plus if one of them fail, the other will continue to work. It's nice to have redundancy in a small package.


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Very nice compact setup you go there. Thanks for the picture. I did manage to find parts diagram for ARB and you can order parts if you need to which is good.

 

[Crom]

...

 

[RoyJ]

I've been doing a ton of research on this. Allow me to share what I've found. But bottom line first, I do agree. My hypothesis is that Air Zenith may have fudged their CFM numbers, or they had a bad meter when they took their readings.

The reason I say this is when I compare the time that the Viair 444C Dual Value Pack takes to fill a 5-Gallon tank (5:30), to the Air Zenith OB2, it's only 16 second behind. Air Zenith quotes a time of 5:14.

I've seen videos of the OB2 filling a 5-gallon tank in about 5 minutes, so I believe that number is real.

The Viair 444C quotes a Max. Amp Draw: 40 Amps. And compared to the Air-Zenith which quotes Max. Amp Draw: 35A. They are close. The CFM numbers quoted by Viair are smaller though.

But looking back at the Extreme Aire's Magnum compressor, that thing has a much larger motor at 1.5 horse power vs. the 3/4 HP of the OB2. I was also wrong in this area, the Magnum is 3.5" longer than the OB2. No question that the magnum is going to be stronger, but at the same time I can't ignore the smaller head size, and my assumption of smaller displacement. I did manage to find pictures of the piston and ring in the OB2, and it's huge. Therefore I don't think the displacements are similar between the two which may explain how a smaller sized motor with larger piston / ring do more with less HP.

When you do get around to testing it, please keep us in the loop on your findings!

I'm really curious of the CFM at different pressure ranges, such as 0-50, 50-100, 100 to 150 and 150 to 200. Without compressor maps this is the closest we get to knowing something's efficiency vs pressure ratio.

Do you have a DC camp meter?

The OB2 does look well built. And to be honest, I think just about every compressor manufacturer fudges the numbers a bit, so the more important thing is how well they preform relative to one another. I wonder how this compares to the Puma (which I believe have been beaten by the dual-ARB).

I also agree the Extreme Aire's head looks small. In addition to heat, the smaller head may cause a lower volumetric efficiency. Seems like they need the forced air cooling more than OB2. I think I read while the Magnum is very tough, they do get extremely hot under continuous service...

 

[WSS]

Extreme aire works great on ours. I can air up all four from 8 to 30 psi in a few minutes. Plus I can air up others too without heat problems. It was mentioned this may be a bad design if dirt or water gets past filter, true, same goes for the engine in the engine compartment, treat it with common sense and maintain it once in a while (clean filter, make sure it is tight and actually in place) and it will last a along time. I have big truck air brake tank between the frame and trans, about 2.5gl and quick connects on the front and back of Jeep foe easy connecting. I use a poly coiled hose 25' long. Works great.

 

[siebermd]

I have a Viair 450, I am very impressed with its capabilities. Fast fill and quiet operation. I really wasnt expecting it to be this good.

 

[kwill]

I just put a Viair 480 under the hood of my 4Runner. It is big but fits nicely. 100% duty cycle at 200 PSI. I've yet to wire it up.

 

[NYresQ]

Has anybody installed a T and run two lines off a portable viair compressor to air up two tires at the same time?

I realize it would take just as long, but then you would have equal pressure in both tires. If you did both fronts and then both rears together, you would have perfectly balanced tires on each axel.

Anyone done this?

 

[Crom]

Thanks Skygear. I read your whole air-mega thread on TW. Good stuff in there!

Extreme aire works great on ours. I can air up all four from 8 to 30 psi in a few minutes. Plus I can air up others too without heat problems. It was mentioned this may be a bad design if dirt or water gets past filter, true, same goes for the engine in the engine compartment, treat it with common sense and maintain it once in a while (clean filter, make sure it is tight and actually in place) and it will last a along time. I have big truck air brake tank between the frame and trans, about 2.5gl and quick connects on the front and back of Jeep foe easy connecting. I use a poly coiled hose 25' long. Works great.

That thing is a beast! :Wow1: Looks real good in there. Thanks for the photos and description.

I just put a Viair 480 under the hood of my 4Runner. It is big but fits nicely. 100% duty cycle at 200 PSI. I've yet to wire it up.

Looks good. Congrats in the install. Can't wait to get mine done.

Has anybody installed a T and run two lines off a portable viair compressor to air up two tires at the same time?

I realize it would take just as long, but then you would have equal pressure in both tires. If you did both fronts and then both rears together, you would have perfectly balanced tires on each axel.

Anyone done this?

Yes. People do that. There is even a contraption that does all four tires at the same time. Here are some pics of such a thing.

I'm still struggling to find a place to mount a tank on my Tacoma. A 5-gallon tank is out of the question, I have no room for that. But I may be able to squeeze in a 3-gallon inside the rear bedsides. I found someone on TW that has done it.

 

[fishEH]

IMO duty cycle and CFM should take priority over a tank. That 3gal tank won't last very long at all when filling up tires. As soon as the tank deops below your low psi setting your compressor kicks on and takes over. From that point your compressor will be running nonstop until your tires are filled. So unless you have air lockers you may want to skip the tank.

Thanks Skygear. I read your whole air-mega thread on TW. Good stuff in there!



That thing is a beast! :Wow1: Looks real good in there. Thanks for the photos and description.



Looks good. Congrats in the install. Can't wait to get mine done.



Yes. People do that. There is even a contraption that does all four tires at the same time. Here are some pics of such a thing.

I'm still struggling to find a place to mount a tank on my Tacoma. A 5-gallon tank is out of the question, I have no room for that. But I may be able to squeeze in a 3-gallon inside the rear bedsides. I found someone on TW that has done it.

 

[Crom]

IMO duty cycle and CFM should take priority over a tank. That 3gal tank won't last very long at all when filling up tires. As soon as the tank deops below your low psi setting your compressor kicks on and takes over. From that point your compressor will be running nonstop until your tires are filled. So unless you have air lockers you may want to skip the tank.

You're right. I'm going to go with a twin ARB and maybe add the single ARB down the road. Tank was only for convenience of blowing dust outta the truck. Scope creep.

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[Streaky]

ARB have slipped way down hill with this twin unit...reliability has been an issue with the crank bolt snapping off. Some owners have modified it by drilling and tapping a larger bolt into the crank shaft. They're also eating fuses at an alarming rate....they're not as good as their Bull Bars thats for sure!

The Magnum Air Extreme takes a pounding and gets my thumbs up any day of the week....I was using the WARN VTC for a while but it started to eat alternators because of it's huge appetite for amps. WARN discontinued it because of 'Quality Issues'....but a real statement was never released.
The Magnum Extreme Air runs my CTIS system, air tools, etc on the Ford F350...nothing comes close although if I was to change it then the the Zenith OB2 would be next up.

 

[Crom]

The ARB did have an issue with the crank bolt it was a 4mm bolt, ARB updated the part to a 5mm high tensile bolt. That's all in the past AFAIK, Source:

http://www.patrol4x4.com/forum/diy-...103101/#/forumsite/20678/topics/103101?page=1



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[Crom]

Thanks to all those who participated in this thread.

For anyone who cared, I ended with an ARB Twin compressor.

I can air up my Toyo 255/85/R16 E tires from 20 PSI to 40 PSI in exactly 1 minute 5 seconds. (72*F, 650' elevation) I couldn't be more happy!

I made it into a portable system, version 2 will be hard mounted.