Big Blue's Transformation

[Gary Lewis]

.... I've come to the conclusion that there is no tank too big. Some say that with a big tank you have to wait until it is full, so that slows you down. But as I said previously, compressors pump more air at lower pressure so once the tank is depleted just use it as a pass-through. Clip the hose to the valve stem and let the compressor run....

I missed this post earlier (I must have been posting at the time).

Yes, compressors pump more volume at lower pressure, but unless you take the tank out of the system you now have to fill up both the tire and the tank at the same time. I think the algebra would work out that you pretty much only need to "air up" the tank once as you air up all 4 tires because what you gained while pumping up the first would be "lost" into the second, so not really lost at all. But unless the tank is big enough to fill all 4 tires pretty much without the compressor running you'll be refilling the tank.

Not to say you don't want the biggest tank you can fit. The advantage of a higher flow rate as you deplete the air tank may well offset the disadvantage of the lower flow rate into the tires as you also refill the tank. And there's the downside of the time it takes to fill the tank to begin with. Not such a huge issue since you're just driving while it does that (it takes maybe ~10 minutes for my compressor to fill my 2.5 gallon tank). But if duty cycle is an issue, or if you need air soon after turning the compressor on it might be (with my air-actuated locker it's more of a risk than just for airing up). I'm not sure how all of that balances out.

For me it's pretty much a moot point anyway. Unless I use my roll cage as an air tank (which I don't want to do for the rust issue), 2.5 gallons is about as big as I can tuck under an early Bronco. And I think I've posted this earlier, but with my 2.5 gallon tank and 33/10.50-15 tires I can only get one tire aired up from 15 - 30 psi before the tank isn't helping me anymore.

Jim - It turns out my portable tank is this 11 gallon one from TSC. And it works really, really well. So I'd be happy to buy another if it'll fit.

Bob - You have a good point, you do have to fill the tank and the tires. So, as you say, the benefit of pumping against lower pressure gets negated by having to fill the larger volume, and at some point it is a wash. But we don't know what that point is.

As for what I did to Big Blue today, I got the winch, aux battery, and interconnecting cable off. (And I got the winch installed on the trailer for next week's trip.)

And, I did a test of an air tank. I took the 11 gallon one to 118 psi on its gauge, which was as high as my shop air system wanted to take it. And I dropped one of Big Blue's LT285/75R16's to 15 psi and aired it back to 30 psi. That took 30 seconds and dropped the gauge to 78 psi. Then I dropped the tire back to 15 psi took it back up, this time overshooting to 32 psi. That dropped the tank to 45 psi and took 60 seconds.

But, I can't get that particular tank in. In fact, it looks like the max height is 8" to keep it concealed as that would put it even with the bottom of the fender. And max width is 16", but most tanks are round so that distance may be irrelevant. If the tank is no more than 8" in diameter the length can be up to 37" long. But if it is 16" wide then it can only be 27" long.

LOL! I saw that Jim posted almost the same dimensions. http://www.garysgaragemahal.com/uploads/6/5/8/7/65879365/ezgif-com-resize-1_orig.gif

 

[ArdWrknTrk]

Jim - It turns out my portable tank is this 11 gallon one from TSC. And it works really, really well. So I'd be happy to buy another if it'll fit.

Bob - You have a good point, you do have to fill the tank and the tires. So, as you say, the benefit of pumping against lower pressure gets negated by having to fill the larger volume, and at some point it is a wash. But we don't know what that point is.

As for what I did to Big Blue today, I got the winch, aux battery, and interconnecting cable off. (And I got the winch installed on the trailer for next week's trip.)

And, I did a test of an air tank. I took the 11 gallon one to 118 psi on its gauge, which was as high as my shop air system wanted to take it. And I dropped one of Big Blue's LT285/75R16's to 15 psi and aired it back to 30 psi. That took 30 seconds and dropped the gauge to 78 psi. Then I dropped the tire back to 15 psi took it back up, this time overshooting to 32 psi. That dropped the tank to 45 psi and took 60 seconds.

But, I can't get that particular tank in. In fact, it looks like the max height is 8" to keep it concealed as that would put it even with the bottom of the fender. And max width is 16", but most tanks are round so that distance may be irrelevant. If the tank is no more than 8" in diameter the length can be up to 37" long. But if it is 16" wide then it can only be 27" long.

LOL! I saw that Jim posted almost the same dimensions. http://www.garysgaragemahal.com/uploads/6/5/8/7/65879365/ezgif-com-resize-1_orig.gif

Yeah, I was looking at the link before finishing your post and thinking. "29-3/4 in. x 21 in. x 13-1/2 in" ... That is going to hang down.

But you're right.

You can go forward (up under the cab) and gain a lot of length.

If you keep diameter down.

Or maybe you go with something a bit deeper (10"?) and take the risk.

Do you really expect to high center in a truck as high as Big Blue?

 

[ArdWrknTrk]

Jim - It turns out my portable tank is this 11 gallon one from TSC. And it works really, really well. So I'd be happy to buy another if it'll fit.

Bob - You have a good point, you do have to fill the tank and the tires. So, as you say, the benefit of pumping against lower pressure gets negated by having to fill the larger volume, and at some point it is a wash. But we don't know what that point is.

As for what I did to Big Blue today, I got the winch, aux battery, and interconnecting cable off. (And I got the winch installed on the trailer for next week's trip.)

And, I did a test of an air tank. I took the 11 gallon one to 118 psi on its gauge, which was as high as my shop air system wanted to take it. And I dropped one of Big Blue's LT285/75R16's to 15 psi and aired it back to 30 psi. That took 30 seconds and dropped the gauge to 78 psi. Then I dropped the tire back to 15 psi took it back up, this time overshooting to 32 psi. That dropped the tank to 45 psi and took 60 seconds.

But, I can't get that particular tank in. In fact, it looks like the max height is 8" to keep it concealed as that would put it even with the bottom of the fender. And max width is 16", but most tanks are round so that distance may be irrelevant. If the tank is no more than 8" in diameter the length can be up to 37" long. But if it is 16" wide then it can only be 27" long.

LOL! I saw that Jim posted almost the same dimensions. http://www.garysgaragemahal.com/uploads/6/5/8/7/65879365/ezgif-com-resize-1_orig.gif

Are we looking for something in the 10-15 gallon range now?

(why can't this damn country get with metric?) 😡

[ArdWrknTrk]

Are we looking for something in the 10-15 gallon range now?

(why can't this damn country get with metric?) 😡

This looks like a good possibility given that the handle, wheels, etc make it seem bigger than the tank itself.

I'd go measure one in store but HF is 20mi away and it's rush hour here.

 

[ArdWrknTrk]

Are we looking for something in the 10-15 gallon range now?

(why can't this damn country get with metric?) 😡

Maybe two 8" x 36" tanks??? (Would fit 8x16x36 envelope)

I'd have to figure the volume, but you lose a lot with diameter...

[Gary Lewis]

Are we looking for something in the 10-15 gallon range now?

(why can't this damn country get with metric?) 😡

Actually, that 37" was going back, back to the rubber wheel well flap. The 8" diameter would allow it to go above the step bar and outboard of the spring mount.

Yes, I'd like to have something around the 11 gallon range as that gets two of the tires up to 30 from 15. And toward that end I've done some calculating. (And I see that you've replied twice while I've been working on this response. So let me get this out and I'll try to respond to your latest posts.)

I measured the existing tank and calculated the volume and came to 10.3 gallons. So, I'm fairly confident in my calculations, but just not my measurements. Anyway, using those calculations an 8" x 37" tank would have 8.1 gallons of capacity. So, we are on the right track.

[ArdWrknTrk]

Actually, that 37" was going back, back to the rubber wheel well flap. The 8" diameter would allow it to go above the step bar and outboard of the spring mount.

Yes, I'd like to have something around the 11 gallon range as that gets two of the tires up to 30 from 15. And toward that end I've done some calculating. (And I see that you've replied twice while I've been working on this response. So let me get this out and I'll try to respond to your latest posts.)

I measured the existing tank and calculated the volume and came to 10.3 gallons. So, I'm fairly confident in my calculations, but just not my measurements. Anyway, using those calculations an 8" x 37" tank would have 8.1 gallons of capacity. So, we are on the right track.

Two 8x36 would be 15.666 gallons (nominal)

You could stagger one back past the spring hanger and one (on the rail) forward under the cab.

But check that HF compressor, it might fit!

[Gary Lewis]

Maybe two 8" x 36" tanks??? (Would fit 8x16x36 envelope)

I'd have to figure the volume, but you lose a lot with diameter...

Ok, that HF tank is supposedly 10 gallons and the overall unit is 30" long. So the tank itself may be 24" long. But it sure looks longer than that 'cause my air tank is 21" long and 12" in diameter. So I'm guessing that the 30" doesn't include the handle.

And, if it measures 8" in diameter I could put two of them side-by-side. Or, I could just go with one of them as it would do two tires from 120 psi.

However, my calc's say that a 30" long tank of 10" in diameter would be have 10.2 gallons of capacity.

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[ArdWrknTrk]

Ok, that HF tank is supposedly 10 gallons and the overall unit is 30" long. So the tank itself may be 24" long. But it sure looks longer than that 'cause my air tank is 21" long and 12" in diameter. So I'm guessing that the 30" doesn't include the handle.

And, if it measures 8" in diameter I could put two of them side-by-side. Or, I could just go with one of them as it would do two tires from 120 psi.

However, my calc's say that a 30" long tank of 10" in diameter would be have 10.2 gallons of capacity.

I'm thinking their "dimensions" are the size of the box it's shipped in.

And the handle isn't attached in the box.

I may be wrong, and I said I'd check the actual item before committing.

But it would get you all the accoutrements!

[Gary Lewis]

I'm thinking their "dimensions" are the size of the box it's shipped in.

And the handle isn't attached in the box.

I may be wrong, and I said I'd check the actual item before committing.

But it would get you all the accoutrements!

I will check it out, but can't do so for a few days as I'm not going to get down into Tulsa where the HF store is.

And, I sure appreciate you taking the measurements as well as looking for a compressor. Thanks!

But, one thing I've not checked out is the space below the tool box and across the front of the bed. I'd rather not use that as it might be good storage for something. And, I'm pretty sure it is very narrow. But, it is also probably twice as wide as what we've been talking in length, so.....