1. Welcome to Tacoma World!

    You are currently viewing as a guest! To get full-access, you need to register for a FREE account.

    As a registered member, you’ll be able to:
    • Participate in all Tacoma discussion topics
    • Communicate privately with other Tacoma owners from around the world
    • Post your own photos in our Members Gallery
    • Access all special features of the site

Superflow MV90/Smittybilt 2781 Modifications

Discussion in 'Wheels & Tires' started by Chickenmunga, Nov 24, 2013.

  1. Nov 24, 2013 at 6:40 PM
    #1
    Chickenmunga

    Chickenmunga [OP] Nuggety

    Joined:
    Apr 10, 2008
    Member:
    #5877
    Messages:
    7,535
    Gender:
    Male
    First Name:
    Mike
    Keizer, Oregon
    Vehicle:
    08 TRD Offroad DC 4x4 with stuff
    All the normal TW BS
    Many of us have purchased a Superflow MV90 or Smittybilt 2781 compressor for trail, safety or towing use. While it is a good value for the money, there's definitely room for improvement.

    I'm going to keep a list of DIY modifications that can be done to these compressor to increase their quality. Please contribute and I will add a link below!

    List of mods
    Pressure switch
    Improved air chuck



    For reference, here is the un-modified unit:

    MV90KitHiRes3004RNTcopy_zps622e515b_139f6aebc6a33e7d41c1efc884933e88a1e6cb0a.jpg

    IMG_20131119_210707_zps6a2225d8_9481013a11b83152375bf7e866f374e58c096b84.jpg
     
    Last edited: Dec 2, 2013
  2. Nov 24, 2013 at 6:40 PM
    #2
    Chickenmunga

    Chickenmunga [OP] Nuggety

    Joined:
    Apr 10, 2008
    Member:
    #5877
    Messages:
    7,535
    Gender:
    Male
    First Name:
    Mike
    Keizer, Oregon
    Vehicle:
    08 TRD Offroad DC 4x4 with stuff
    All the normal TW BS
    Pressure switch mod (Under $50)


    Intro
    One of the things that gripes me about this unit is that it is continuously blowing. If you need to replace the stock air hose, you are most likely going to get an off-the-shelf tire chuck that only blows when you depress a handle or if it's mounted to the tire. If the unit is on and you don't have things all hooked up, pressure builds up until it reaches a critical level and escapes out of the path of least resistance. This should be the blow-off valve, but for me, it was the cheap hose

    IMG_20131124_184849_zpsf46c3ec5_4b68a9635637e001a6c5fc4fa91f643ad5e06d7f.jpg


    On all of the home compressors you will ever see, this situation doesn't occur because they have what is known as a pressure switch, which is a mandatory safety item. This device will sense when the pressure in the compressor tank is too low, and will kick on the motor. Once a preset pressure is reached, the switch senses this and automatically shuts off the motor.

    My goal is to add such a switch. Since our compressors are tankless, the pressure is held in the steel hose that doubles as the carry handle. When you attach a hose, that acts as a portion of the 'tank'.

    From the pressure switches I've researched, they have a turn off pressure of 200 PSI or less, while hoses are rated between 100 PSI - 400 PSI. Based on the numbers, as long as I'm not buying the cheap hose, the pressures are well within acceptable ranges.

    HOWEVER, AS ALWAYS, I am not responsible for any modifications you perform.


    Parts needed
    Some of these parts can be hard to track down since most compressor shops only deal with customers who have 1000 PSI units or bigger :( As a result, here's a result of off-the-shelf and easy to buy parts.

    These parts are from Home Depot:

    These parts you will need to find online (at least I can't find them local):
    • VIAIR 90223 90 / 120 PSI (30A) sealed pressure switch. My best price was from Summit Racing
    • VIAIR 92812 1/4" NPT male to 1/8" NPT female reducer. I again purchased from Summit Racing. WARNING! Do not buy a BSP to NPT reducer! the threads are not compatible!!

    Note that you can buy unsealed pressure switches as well, which cost about half. However, I live in a wet climate and prefer not to get zapped :rain:
    You can buy from other companies than VIAIR parts, but I couldn't find anything easily.

    Misc. parts needed
    • Wire
    • Wire sleeving
    • zip ties
    • heat shrink
    • female spade connectors and butt connectors, OR solder.... whatever your desired method of connecting wires together is

    Tools needed
    • Basic socket and wrench set. Maybe a monkey wrench, these nuts are crappy
    • Allen wrench set. I think I used a 5/8"
    • Wire strippers
    • Crimping tool
    • Soldering iron (at minimum, this will be used to de-solder some connections)
    • Multimeter
    • something to melt heat shrink

    Stuff needed for testing
    • Car battery
    • Compressor hose that is compatible with the compressor, minimum pressure rating of 200 PSI
    • simple cheap air blow gun


    Process
    1. Unplug the compressor (duh!)
    2. Unscrew the blow-off valve. If there's any gritty stuff on the threads of either the compressor or the valve, clean it up. You might have to get a knife and scrape it off a bit.
    3. Put plumber's tape on the threads of the following items:
      • Blow-off valve
      • tee
      • both ends of the male-male coupler
    4. Attach the blow-off valve to one of the female ends of the tee
    5. Attach the female-female coupler to the male end of the tee
    6. Attach the male-male coupler to the other end of the female-female coupler
    7. Take the entire assembly and screw it into the compressor

    IMG_20131124_182040_zpsbb695834_06379b30e5d0b6745fe1917ab6241f7095397cfd.jpg

    Apply plumber's tape to the reducer
    Attach the reducer to the pressure switch
    Attach the other end of the reducer to the tee

    IMG_20131128_110930_zpsad43af73_39ac31694be0a50fb692006da60aee8381efa481.jpg

    • Remove the black base plate from the bottom of the compressor
    • Remove the front L bracket that is held on with the Allen bolts
    • Remove the NPT fitting and washer from the compressor's handle. Clean off any plumber's tape
    • Remove the heat shield by removing the Allen bolts
    • At this time, you can pull back the plastic cup that is holding the electronics
    • Making sure the switch is in the OFF position, connect the compressor to the car battery
    • Turn the multimeter to voltage DC
    • Take the black lead of the multimeter and ground it on the exposed, unpainted metal of the compressor
    • Take the red lead of the multimeter and test each prong of the power switch to determine which is the incoming hot lead (reads a voltage) and which is the outgoing lead (reads zero). For me, the outgoing was in the middle of the switch as shown below.
    • De-solder the incoming lead from the switch. YOU WILL NEED TO ATTACH TO THIS WIRE LATER ON, DON'T CUT IT OFF OR ANYTHING DUMB LIKE THAT! Clean up the prong as well by removing the excess solder.

    IMG_20131201_142021_zpsfcaba415_359176a93065219310a599b538ef2ff82adb8b39.jpg

    We need to send some wires from the factory on/off switch to the new pressure switch.
    Cut a hole in the plastic cup for the wire leads to exit. If you look on the bottom of the cup, there's some pre-made tiny holes. I used the opportunity to make them bigger. Bonus points since these are on the bottom of the cup, which hides the entry for aethetics and minor water resistance


    IMG_20131201_141931_zps30aeec3e_5ed5ecd2af622a7608155df0e2be3b98e99ac403.jpg

    Now, it is time to wire the pressure switch. The idea is to make it inline so that it will trip the system when pressure is reached

    Schematic_zps1ab4eb49_26e49dbea88948a9a84f328fea02015f4a7d93c8.jpg

    • Using your spade connectors and butt connectors (or solder), your wire, and your heat shrink:
      • connect one end to the outgoing lead of the factory switch
      • connect the other end to the pressure switch (doesn't matter which wire)
      • connect the remaining end of the pressure switch to the wire that you de-soldered from the earlier steps.
      TIP: Keep enough length of wire to make any repairs easy to perform. You can shove some excess inside the cup.
    • Re-assemble the cup, metal plates, all that good stuff. Make sure to put some plumber's tape on the NPT fitting before attaching it. Don't overtighten anything, it doesn't need much.
    • Put on the wire sleeving and zip tie it up purty

    IMG_20131201_205112_zps05a555ae_2e0a886cac565812c6dab7bb15e96645ecd7536b.jpg

    I just realized I should have probably rotated my sleeving so the opening is pointing down, oh well...

    IMG_20131201_205201_zps539785ba_2024f39fbcee1f0793ac4faa1cce4749920af1fc.jpg

    Testing

    This part can feel kind of sketchy, so I tried doing the best I could to protect against accidental explosions or mayhem, but still I'm wishing I had a better way to test. Anyway, here's what I did, trying to minimize any potential damage from problems:
    • Drive your vehicle into the garage
    • Open the garage door enough for vehicle exhaust to escape (if your vehicle is on)
    • Put compressor on ground next to driver tire. Put a wood board between the vehicle and the compressor in case anything happens
    • Attach the compressor hose (rated at 200 PSI or above) to the compressor
    • Attach the air blower to the hose
    • Holding the button down on the air blower, turn on the compressor. The compressor should kick on and your blower should start blowing. This is how your compressor normally operated before modding
    • Continue to hold down the air blower and walk into the house or behind a sturdy wall
    • Throw the air blower/hose around the corner and shut the door (if you have one).
    • Proceed to panic as you realize you've just trusted the internet and imagine how you've potentially created a bomb that will destroy your vehicle and kill someone, oh God what was I thinking, why didn't I just spend the extra $400+ and buy a compressor with a pressure switch from the factory that's been tested by professionals, oh God I'm an idiot...
    • Realize that the compressor has shut itself off and the pressure switch has done exactly what it needs to do (note the compressor will cycle occasionally if there are any air leaks). Also realize the blow-off valve acts as a protection device for overpressure
    • Congratulate yourself on what a huge success this was and how the internet is a magical place once again, oh, I'm sorry I ever doubted!!

    (FYI, if you have a better test setup, I'll erase this suggestion and put yours in here :) )

    More to come later... test video!
     
    Last edited: Dec 2, 2013
    gmanrider9 and GHOST SHIP like this.
  3. Nov 24, 2013 at 7:57 PM
    #3
    Chickenmunga

    Chickenmunga [OP] Nuggety

    Joined:
    Apr 10, 2008
    Member:
    #5877
    Messages:
    7,535
    Gender:
    Male
    First Name:
    Mike
    Keizer, Oregon
    Vehicle:
    08 TRD Offroad DC 4x4 with stuff
    All the normal TW BS
    Improved air chuck (about $25)

    Unmodified compressors
    The MV90/2781 compressors are unique in that their built-in chuck is constantly blowing. I haven't found an aftermarket replacement that is set up like that.
    The best option is the VIAIR 00025 hose (purchase from Amazon here).
    The benefit is that the guage is more accurate (typically within +/- 5 PSI from my experience), and it has a built-in deflation option.

    WARNING! If you use this with an unmodified compressor, you must follow these steps when airing up tires:
    1. Attach hose to tire
    2. Turn on compressor
    3. Monitor pressure. When tire has reached desired pressure, turn off compressor
    4. Repeat for the other tires.
    If you detach the hose from the tire without turning off the compressor, you will either rupture the hose or trigger the bleed-off valve.

    [​IMG]

    Modified compressors

    If you have done the pressure switch mod, you can use whatever you like. However, I highly recommend the ARB inflator chuck:
    • the tire gauge is very accurate
    • the chuck has a bleed-off button to reduce pressure. Doubles as a deflator!
    • the unit can be used without being hooked up to a compressor, so you can use it as a gauge/deflator by itself

    [​IMG]
     
    GHOST SHIP likes this.
  4. Dec 2, 2013 at 12:57 PM
    #4
    Chickenmunga

    Chickenmunga [OP] Nuggety

    Joined:
    Apr 10, 2008
    Member:
    #5877
    Messages:
    7,535
    Gender:
    Male
    First Name:
    Mike
    Keizer, Oregon
    Vehicle:
    08 TRD Offroad DC 4x4 with stuff
    All the normal TW BS
    Pressure switch mod section updated
     
  5. Dec 6, 2013 at 3:51 PM
    #5
    skygear

    skygear                    

    Joined:
    Nov 6, 2011
    Member:
    #66558
    Messages:
    8,414
    I copied your posts. Much Love'
     
  6. Aug 6, 2017 at 7:11 PM
    #6
    GreeGunc

    GreeGunc Full of regret

    Joined:
    Sep 6, 2014
    Member:
    #137721
    Messages:
    3,505
    Gender:
    Male
    First Name:
    Jacob
    North GA
    Vehicle:
    1st gen 3rz+18' inferno OR 6spd
    2lo mod. PIAA 510s. Green Floor Lights. Green dash swap. Axle dump exhaust. Husky floor mats. Moto metal mo970's. Shrockworks. Sundown sa-8. 9.5xrc. Kings
    Don't mean to revive an old thread but how is this pump doing? May be getting the smitty 2781 instead of the viair 444c I've been looking at
     
  7. Aug 7, 2017 at 8:57 PM
    #7
    Chickenmunga

    Chickenmunga [OP] Nuggety

    Joined:
    Apr 10, 2008
    Member:
    #5877
    Messages:
    7,535
    Gender:
    Male
    First Name:
    Mike
    Keizer, Oregon
    Vehicle:
    08 TRD Offroad DC 4x4 with stuff
    All the normal TW BS
    Still works just fine. Every time I go make a video somebody decides it's time to mow the lawn, or land a plane, or drive up and down the street with their chopper... it's like the world doesn't want me to make a video review for this, and I've tried multiple different days in different states.
     
  8. Aug 8, 2017 at 2:54 AM
    #8
    GreeGunc

    GreeGunc Full of regret

    Joined:
    Sep 6, 2014
    Member:
    #137721
    Messages:
    3,505
    Gender:
    Male
    First Name:
    Jacob
    North GA
    Vehicle:
    1st gen 3rz+18' inferno OR 6spd
    2lo mod. PIAA 510s. Green Floor Lights. Green dash swap. Axle dump exhaust. Husky floor mats. Moto metal mo970's. Shrockworks. Sundown sa-8. 9.5xrc. Kings
    Haha, I gotcha. Belive I'll get it over the viair
     
  9. Dec 19, 2017 at 2:04 PM
    #9
    punkn

    punkn New Member

    Joined:
    Dec 19, 2017
    Member:
    #238898
    Messages:
    1
    Gender:
    Male
    First Name:
    RJ
    Vehicle:
    Jeep
    lots
    Great write up. I just picked up 2 Smittybilt compressors. I am going to put them in my Jeep and add a 2.5gal air tank. The reason for my post is this. Remember the odd Japanese air fitting that comes out of the handle? It is metric 12x1.25 thread. I ordered 2 male M12.5x1.25 x female 1/4npt fittings. They screw into the air compressor and has a female 1/4" pipe thread for a real hose. Got mine from Hydraulic Hoses online. Once again, a great write up.
     
  10. Jan 11, 2018 at 8:22 AM
    #10
    Lord Humongous

    Lord Humongous The Ayatolah Of RockNRolla

    Joined:
    Jan 14, 2016
    Member:
    #174960
    Messages:
    2,315
    Gender:
    Male
    AZ
    Vehicle:
    Inferno 3rd gen trd offroad 4x4
    https://www.tacomaworld.com/threads/lord-humongous-gigahorse-build.436524/
  11. Jan 11, 2018 at 9:49 AM
    #11
    Chickenmunga

    Chickenmunga [OP] Nuggety

    Joined:
    Apr 10, 2008
    Member:
    #5877
    Messages:
    7,535
    Gender:
    Male
    First Name:
    Mike
    Keizer, Oregon
    Vehicle:
    08 TRD Offroad DC 4x4 with stuff
    All the normal TW BS
    Many people have used these units as dedicated OBA, but it is a larger unit. If you are cramped for space, it's probably not going to work.
     
  12. Jan 11, 2018 at 11:19 AM
    #12
    Lord Humongous

    Lord Humongous The Ayatolah Of RockNRolla

    Joined:
    Jan 14, 2016
    Member:
    #174960
    Messages:
    2,315
    Gender:
    Male
    AZ
    Vehicle:
    Inferno 3rd gen trd offroad 4x4
    https://www.tacomaworld.com/threads/lord-humongous-gigahorse-build.436524/
    Thanks for the heads up. I have my arb compressor in a tuffy bed box which is already somewhat tight
     
  13. Jan 11, 2018 at 3:38 PM
    #13
    Chickenmunga

    Chickenmunga [OP] Nuggety

    Joined:
    Apr 10, 2008
    Member:
    #5877
    Messages:
    7,535
    Gender:
    Male
    First Name:
    Mike
    Keizer, Oregon
    Vehicle:
    08 TRD Offroad DC 4x4 with stuff
    All the normal TW BS
    If Amazon is correct, the unit is about 15 x 11 x 12 inches, and you need to maybe add a bit of length for the hose to connect and bend.
     
  14. Jan 11, 2018 at 5:58 PM
    #14
    Lord Humongous

    Lord Humongous The Ayatolah Of RockNRolla

    Joined:
    Jan 14, 2016
    Member:
    #174960
    Messages:
    2,315
    Gender:
    Male
    AZ
    Vehicle:
    Inferno 3rd gen trd offroad 4x4
    https://www.tacomaworld.com/threads/lord-humongous-gigahorse-build.436524/
    I did see that but I've noticed that dimensions sometime refer to the box it comes in and not the actual unit size:der: Maybe I'll shoot smittybilt an email.
     
  15. Oct 9, 2018 at 12:23 AM
    #15
    Plumber111111

    Plumber111111 New Member

    Joined:
    Oct 9, 2018
    Member:
    #268786
    Messages:
    1
    Gender:
    Female
    First Name:
    James
    Excellent write up! One thing you left out or I may have missed was what gauge electrical wire?

    I think a nice upgrade would be to install quick disconnects on each end so I don’t have to pop the hood and hook up the alligator clips. Can hang wire low under winch bumper and cap off.

    Would like to know what gauge wire so can get correct size! Looked everywhere and even went to the website but that information is just not listed.
     
  16. Oct 26, 2018 at 9:22 PM
    #16
    Chickenmunga

    Chickenmunga [OP] Nuggety

    Joined:
    Apr 10, 2008
    Member:
    #5877
    Messages:
    7,535
    Gender:
    Male
    First Name:
    Mike
    Keizer, Oregon
    Vehicle:
    08 TRD Offroad DC 4x4 with stuff
    All the normal TW BS
    My dad's an electrician. I just used some old high grade wire he had left over from the early 80s that was out in the shop.
     
    Greg.Brakes.Tacos likes this.
  17. Nov 19, 2019 at 7:36 PM
    #17
    ToyotaBurrito

    ToyotaBurrito Well-Known Member

    Joined:
    Jul 6, 2018
    Member:
    #258463
    Messages:
    196
    Vehicle:
    2013 AC Sport MT
    Great write up, thanks for sharing. After I tried sourcing the parts from multiple places, nobody has them all (Summit Racing almost did, but then I had to spend $10 shipping), I began to wonder if I could just use a (self-powered—piezo electric) remote 12V relay, something like this:

    https://www.amazon.com/12V-Controller-Self-powered-Transmitter-Electronic/dp/B07FTC943F

    and just combine it with a 40 amp relay (Amazon also sells 12V 40A remote relays, but the remotes use watch batteries and I want to avoid needing one when I don't have it).

    For $20 (already have some relays) and less assembly, I can just turn the compressor on and off at each tire. Am I crazy?

    Also, if only using the pump for inflating tires and things, one could replace the blow off valve ("air safety valve") with one that has a lower PSI rating, like 100 or 125PSI (https://www.amazon.com/Kingston-ASME-Code-Profile-Safety-Pressure/dp/B006U4IM82).
     
    Last edited: Nov 20, 2019
  18. Dec 10, 2019 at 5:42 PM
    #18
    cwieland

    cwieland Member

    Joined:
    Aug 21, 2013
    Member:
    #110891
    Messages:
    7
    Gender:
    Male
    Lake Elsinore, CA
    Vehicle:
    2002 Tacoma TRD
    Super Charger 7th Injector
    Great write up, thanks! Is it still working? I was curious, the pressure switch you spec'd is 30 amps and the unit is 45. Have you had any problems? I want to go ahead and do this.
     
  19. Feb 4, 2020 at 4:37 PM
    #19
    john221us

    john221us Well-Known Member

    Joined:
    Dec 22, 2018
    Member:
    #276597
    Messages:
    302
    Gender:
    Male
    First Name:
    John
    Rocklin, CA (Sacramento)
    Vehicle:
    2019 Toyota Tacoma Limited
    Bed Mat
    Great write up, old thread. I just did the mod on a brand new Smittybilt 2781 and have a couple of updates that should help. Everything is still valid:
    1. Mine had a 60 Amp relay already installed (under the cover you unscrew where the switch is). You install the pressure switch between the switch and the relay. No need to get your multi meter out.
    2. It is worth noting that while the compressor says it is 150 PSI, the operating pressure is 120 and the blow off valve blows well below 150. I originally installed a 110 / 140 pressure switch and it didn't turn off (blow valve kept blowing). I then installed a 90 /120 and it operates as expected. I just used a cheap one off of Amazon and it works great https://www.amazon.com/gp/product/B07XYQJ19P/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1
     
  20. Apr 11, 2020 at 4:59 AM
    #20
    JimElectric

    JimElectric New Member

    Joined:
    Mar 20, 2020
    Member:
    #322606
    Messages:
    1
    Gender:
    Male
    Hey!

    You use a 30A Pressure Switch in an Air Compressor with a Maximum Amperage Draw: 45A.
    Does the Air compressor has an Internal Relay or you just wired the Original switch in parallel with the Pressure Switch.

    If you wired in parallel the 2 switches, there is a problem because you will fry the Pressure switch when your Air Compressor asks for more than 30A.

    I am asking because I want to the same mod in a T-Max air compressor (quite similar to the Superflow and the Smittybilt Compressors).
     
To Top