I Do This For The Glory
Join Date: Dec 1999
Location: Nobleboro, Maine
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Re: help a Suzuki-guy? - airtank-mobile-winchbumper
Hey there, nice Zuki! Still running the stock shackles, surprised you haven't ripped them off by now. How do the RS9000's work on such a light rig?
I did some quick math, and:
your bumper will have a capacity of 0.3125 cubic feet.
Your tires each have a capacity of 1.83 cubic feet (assuming "true" 31's)
So, to air up from, say 5 pounds to 20 pounds (I've wheeled a Zuki before, they need a LOT less air in the tires). So the delta is 15 psi.
Assuming constant temperature, we'll use Boyle's Law to find the pressure needed in the tank to pump up the tires back to 20 psi.
Pf/P = V/Vf
where Vf and V are the final and initial volumes, and Pf and P are the final and initial pressures
So, doing some quick math, it looks like:
15 psi/"X" = 0.3125 cubic feet/7.32 cubic feet (all 4 tires)
Solving for "X", we get (15*7.32)/0.3125, so "X" = 351.4 psi.
So you'd need approximately 351 psi in your bumper to air all 4 tires back up. I don't think you're going to get that from a garage air compressor. The only thing you can do is
1) put in a larger bumper
2) don't air up/down your tires as much
Otherwise it sounds great. I would also add a few drains, one at either end, to drain any condensation out of the bumper. With what I've posted here, you should be able to play around with bumper sizes and pressures. If you need a hand, let me know, glad to help out.
If we back calculate using 120 psi from the standard shop compressor, I find a volume of 0.915 cubic feet is needed, and with a width of 60" (5 feet), the bumper would need to be 5" x 5.25" to work, or be 5.8" in diameter if you used a round tube.
Winter Harbor, Maine
'81 CJ-8 Scrambled!
It's a Jeep, Chevy, IHC kinda thing!