NVH and using software for it

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  • Witsend
    Banned
    • Nov 2012
    • 2942

    NVH and using software for it

    I've used the mechanics stethoscope and chassis ear to narrow down the possibilities of a source of noises, but sometimes you get a vibration you feel with a droning, or booming sound at certain rpm, or range and an underbody inspection is not conclusive..
    Here is a good software source for diagnosing the source of vibration with an EVA (Electronic Vibration Analyzer). I'm surprised Snap On hasn't incorporate an EVA function into a portable oscilloscope ,it could have an external vibration pickup like an SPX/OTC?produced EVA , and could list and capture the 3 most prominent vibrations at the desired RPms you want to capture it, but because it's incorporated into the scope be able to graph an event so you could compare to the software graph. I think OTC makes most of the EVAs that dealers use and see some can be purchased used on Ebay in the $500 range

    Vibration diagnosis for cars, trucks, SUVs, and commercial trucks using the NVH App. Automotive Technicians can increase their income!
    Last edited by Witsend; 07-07-2014, 06:56 AM.
  • Skip
    Super Moderator
    • Apr 2008
    • 605

    #2
    Reading the vibration frequencies is one thing. Understanding the math to determine the component that is causing the vibration is another. Each of those 3 frequencies is based on the rotational speed of the component(s) at a given MPH/RPM. Most techs just use an assometer. Don't get me wrong, I like the EVA, but I doubt there is enough money to be made for SO to get involved.

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    • Witsend
      Banned
      • Nov 2012
      • 2942

      #3
      EVA and doing the math

      I think there is money to be lost though if our Asses just Assume and mis diagnos the problem and it makes a u or me out of our asses.
      The main reason for the Vibrate Software, is that it's supposed to take most of the math out of the equation.
      I'm just thankful NVH problems are few and far between that my assometer and stethoscope can't figure out. I'm thankful I don't have to deal with any of these, it's a pain in the *** enough to find a spreader in the shop for my *** dealing with a Dana than worrying about correct set up on one of these things. LOL

      Last edited by Witsend; 07-07-2014, 11:30 AM.

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      • Skip
        Super Moderator
        • Apr 2008
        • 605

        #4
        The OTC EVA displays 3 frequencies with their amplitude. Determining where they come from requires the math. They do make one that hooks into the DLC and if it recognizes the VIN will read all the info and tell you which component is the cause. Last I looked those are about $5,000.

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        • Skip
          Super Moderator
          • Apr 2008
          • 605

          #5
          I now see that they have upgraded the EVA since I started using it and it does the math.

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          • Witsend
            Banned
            • Nov 2012
            • 2942

            #6
            I think the EVA just records the 3 most prominent vibrations at the RPM and trans range you want to save the data , and you refer to the software and connect the dots. The Vibrate 5.1 software is about $180 and a used EVA isn't too pricey. Wouldn't be surprised if a lot of the EVA internals are based off ancient OTC monitor 2000, with something special like a 1988 Denso knock sensor built into a transmission pan magnet or something similar , surely Snap On could build something a lot more fancy and expensive than the SPX EVA , (lol) but they could just provide an optional vibration probe for $300 as a scope add on like a pressure transducer that would work with future software version 15.4 or higher , and you might even be able to run Vibrate 5.1 on a Verdict or Verus.
            Last edited by Witsend; 07-07-2014, 12:39 PM.

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            • maven
              Senior Member
              • Mar 2014
              • 269

              #7
              GM has issued the PICO scope and software as its replacement for the EVA2 and its version of the Vibrate Software.

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              • Witsend
                Banned
                • Nov 2012
                • 2942

                #8
                The Pico NVH kit as a replacement for the EVA 2 looks like it also has a microphone for accoustical use . The Scope can plot a real cool looking 3D topographical landscape of the vibrations or noises retreived on your Laptop screen, which is great hardware upgrade , but on the software end with the database of multiple makes and model cars , with known trans ratios, final drive ratios, engine options , pulley and tire sizes, already in the software and taking a lot of the math out of the equation on your end , I'm sure the regular tech would want to run Vibrate 5.1 because he wants to keep it simple . If it going to take over an hour to figure out , measuring pulley diameters , entering gear and rear end ratios or ends up looking like a toss up of it being 2 expensive parts , and or extra teardown time to determine . I would gladly ship it to them .
                I'm thinking that GM software is superior , and just has you enter a VIN and it knows what it's got as built as stock, but if they see they are dealing with some sort of Hillbilly, Donk, Low Rider Hybrid and have to do any math you know you'll see it by you sooner or later.

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                • maven
                  Senior Member
                  • Mar 2014
                  • 269

                  #9
                  The GM software even integrates the MDI(J2534 module) into it and can read and utilize data stream at same time. theres no calculations unless its non stock equipment(wheels/tires/gears) but then Im doing under warranty anyway and Im not worried about it being fast. It even shows you where to put hose clamps to alleviate propshaft vibrations. (this is actually why it was released.)

                  I honestly havent used the EVA, EVA2 or the new PICO NVH more than ten times in the last dozen years. Been lucky I guess.

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                  • Witsend
                    Banned
                    • Nov 2012
                    • 2942

                    #10
                    As a creature of (bad) habit I would probably still use My Assometer, stethoscope or a chassis ear first , but if I'm not really confident and it looks like an expensive either or deal It's nice to be able to Dazzle the customer with a high tech 3D color graph printout and show him or her , it's still an Einie , meanie, even though we definately eliminated the Moe.

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