MikekiM

Am looking at the various options, gearing up for beach season.

I am just getting started and as yet have only narrowed it down based on my budget and the complexity level of the install. Now it's time to thin out the contenders.

Can someone please help me understand Duty Cycle? What it is, how it impacts performance and why I should pay attention to it.

My use will be primarily for airing up after a beach excursion.

Hskr4x4

Don't waste your money on onboard air then if mostly for beach stuff. Just buy a VIAIR 400 so you can still fill your 35s.

Other brands on market That I would look into

ARB
Smittybilt

This is just a site I used to get you example links

/www.4wheelparts.com/Winches-and-Winch-Accessories/Smittybilt-Air-Compressors.aspx?t_c=18&t_s=190&t_pt=100437&t_pl=5 822

://www.4wheelparts.com/parts/viair-compressor/viair-portable-compressors.aspx I'd get the 400 if you have 35s

://www.4wheelparts.com/Towing/ARB-Air-Compressor.aspx?t_c=67&t_s=3&t_pt=4644&t_pl=393

You will have to copy from www on

Hskr4x4

The VIAIR link I sent you will give you enough examples of what each will do. Also going portable will only cost you max off $200. Onboard you have to buy mounting hardware and all the other bs, oh and install time...

GreenJK07

You can also save some green by getting a cheap portable pump from the local parts store and hard wiring it to your battery. It may take a little longer than the Vlair and other pumps that are expensive, but only cost $60 and work fine.

MikekiM

Thanks all.. As I usually do, I realized a few facts I should have added to make this more relevant to my situation...

• If you didn't check already, I am on 33x12.5's
• Yes, primarily beach excursions so I am looking to air up four 33's from around 15 psi
• Installation.. no big deal. That's part of the fun!
• I have a 2 door, so there is trade off when adding a portable unit.. It's one more thing to carry. A hard install can use otherwise wasted space in the engine bay
• I have an el-cheapo portable.. I think it's a Central Machine from HF. It belongs in my wife's cross-over for emergency use only.
• My budget can accomodate $300 - $400 if needed.. Less is fine though.. there is no shortage of other mods I would like to do

I read/watched Woods Torture Test on the Viair units sold by Dominion Offroad and man, those are impressive. I could have those either portable or hard installed. The ARB units seem cost effective but they are what led me to the question about duty cycle.. one was [gulp] 10% duty cycle.. Skip that one. The other I found was 30%. Better but not perfect. There is a Viair Constant Duty unit, which might be overkill in the other direction given how much use it will get. On a recovery vehicle it might be perfect, though now that I think about it my family would probably appreciate not having to wait for the compressor to cool down.

I wouldn't mind having a storage tank. Air horns would be cool too.

But referring again to Woods Torture test, the value of the tank is limited.. according to Woods.. " If I fill the [2 gallon] tank to 145 PSI and turn the compressor off, the tank will fill one tire from 9 PSI to 18 PSI." Meh... other than for air horns, I don't know that I see value in that, unless I am missing something which is entirely possible. Someone enlighten me.

There is a write-up on the forums here on how someone installed a Smitybilt unit behind the right rear tail light in the cubby that is otherwise unused space. Not sure how well it cools in there, but that is worth re-reading.


Thanks for the info on the duty cycle.. that was my initial question. Does your Viair 200 fill your 35's without shutting down? Is it a portable unit or can it be hard-installed as well?

Now, if I am understanding duty cycle correctly, it is measured at 100psi. So, with a unit that is rated 30% duty cycle at 100psi, should we expect it to stall for cool-down at all when operating at a much lower psi? Does simple math work here? If I am running at one third psi, can I expect three times the duty cycle efficiency? 90% duty cycle at 33psi?

I am curious if those units that are installed underhood need the hood to be open to run efficiently or if the hood can stay closed.. that would impact my decision for where to mount the air pickup if I go hard installed.

Jtrain496

Duty cycle is also a trade off with cfm output. A Viar 400 has only a 33% duty cycle but puts out almost twice as much air as a 450 with 100% duty cycle. My 400 will fill 33s from 15 to 30 psi in about 3 min per tire without shutting down.

It has an intake filter that you can attach a hose to so it intakes from the cab or anywhere outside the engine bay. I mounted it under the hood and ran a line with a chuck to the from bumper. Then ran a switch to the dash so I don't have to open the hood to air up. Works great for me.

MikekiM

That's good to know.. very good. Thanks

Did you use the Dominion Offroad kit?

Where did you mount the remote filter/intake?

Jtrain496

I bought the compressor at my local shop $200 the Dominion Bracket $50 and then some 12ga wire and a switch from autozone. For the remote filter you just need some tubing and a couple of screw in parts, but you can get a kit for under $10 online by googling it.

MikekiM

You could extend the line quite easily. Run it in the engine bay on the frame rail and head forward or back, which ever way you prefer and put the QR chuck by the front or rear bumper. It can be done by snaking through the frame rail or tuck and zip tie to the rail. At least that's what I have read.

mhaines

I have the ARB under hood setup also. I took an old air hose and cut it down then ran it through engine bay to front bumper. I leave it plugged into the ARB and the quick release end is right next to my winch. When I need to air up, I just turn on the compressor an connect the airhose to the coupler. Don't have to open the hood that way