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Am I going to blow up with my car?

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  • Am I going to blow up with my car?

    So I just scored a cng contour here in Utah. I will say buying a cng in Utah is harder than finding a good looking, single, non-Mormon to date.

    There were people runnning around the car lot trying to swipe my contour from me. I had two car dealers back out on a deal to me the week before only to sell to someone the same day at a higher price.

    It is ridiculous. But now that I have my coveted cng vehicle, i have a question. My manual says my tank is rated to 3000 psi. The tesoro by my work pumps at 3600 psi. When I filled up it clearly read 3600 psi as it neared full.

    Am I going to eventually blow myself up if i continue to use this tesoro and fill my tank to 3600 when it is only a 3000 psi tank?

    Thanks for the help?

  • #2
    Re: Am I going to blow up with my car?

    I personally would not let it fill completely


    • #3
      Re: Am I going to blow up with my car?

      First, you're not going to blow yourself up. The tanks are rated at 3000psi 'working pressure' but usually at least twice that for 'burst pressure.' Use at 3600 may weaken the tank over 10 or 20 years. Frankly, I think that repeated 'fast fill' to the rated pressure does more damage over time than 'slow fill' to a somewhat higher pressure.

      Next, you shouldn't be able to put a 3600 nozzle on a 3000 system, just like when they came out with Unleaded and you couldn't put a Leaded nozzle on an Unleaded car. Most dispensers have both 3000 and 3600 sides so maybe you were using the 3000 one?
      02 GX
      01 GX
      03 Crown Vic
      06 GX
      Home Fueler


      • #4
        Re: Am I going to blow up with my car?

        You probably didn't fill up at 3600 psi. There are no 3600 psi public stations in Utah (technically), at least that is my understanding. My understainding (and someone correct me if I am wrong) is that prior to Questar making any stations available to the public, they needed to come up with a solution to the fact that there are still many 3000 psi machines on the road. Their solution was to make all public stations 3300 psi (halfway between 3000 and 3600). This prevents 3000 psi rated machines from getting more than 10% overfill (which they can SAFELY and EASILY handle without affecting tank life), but also means that those of us with 3600 psi rated vehicles never really get a 'good' fill.

        You are definitely not going to blow up.

        Just for fun, Check out this video

        Last edited by Timon; 05-22-2008, 02:15 AM. Reason: Added inline google video.


        • #5
          Re: Am I going to blow up with my car?


          Your tank is rated for a service pressure of 3,000 psi, but under the NGV2 specification, it allows for a fast fill of upto 1.25 times service pressure (3,750 psi in your case). Just as long as when your tank cools down from the fast fill, it is at 3,000 psi (yout tank heats up during a fast fill - Gas Law - Pv=RT). I design these kinds of tanks for a living...I wouldn't let 600 psi worry you. Now, if you were filling it up to 4,500+ psi every time, then I would be concerned.
          Mountain Green, Utah
          2003 CNG Cavalier
          2003 CNG Silverado 2500HD


          • #6
            Re: Am I going to blow up with my car?


            So, are you saying all the good looking single gals in Utah are Mormons? There are also a lot of good looking married gals in Utah that are Mormons, too. I'm married to one of them. But, I promise, we don't have a monopoly on good looks. Keep trying and let us know how you do.

            As far as the pressure of pumps around SLC, when I filled up at the Questar one at about 1100 West 2nd South, it showed 3600 on the pump. I think there may be other 3600 psi pumps around. I would tend to agreed with freedml about the working pressure and burst pressure.



            • #7
              Re: Am I going to blow up with my car?

              You're not going to blow up, the burst pressure of the tank is much higher but before you even reach that point the PRD will blow off. But trust me as time passes you will want to blow it up.

              see this thread which is just below yours on the forum:
              and the compuvalve is just the beginning !
              Last edited by CNG MOTORS; 05-21-2008, 08:14 AM.

              2003 Hummer H2 bi-fuel
              2000 GMC Yukon XL bi-fuel
              1999 International 4700 dual-fuel
              2007 Chevy Avalanche bi-fuel

              FMQ2-36 Fuelmaker w/ 24 GGE cascade


              • #8
                Re: Am I going to blow up with my car?

                Kirkbenge, great Video.

                Some guy rear-ended my Pickup doing about 50 miles an hour. The CNG tanks took a direct hit from my bumper being forced in to the CNG Tank's taps.

                All that happened, is all the CNG just vented up into the atmosphere.

                The attending Fire Department guys were pretty relieved to see my Natural Gas Sticker, which identified the fuel on board my pickup.

                I hate to think what would have happened if I had of had Propane tanks.

                Stu Man


                • #9
                  Re: Am I going to blow up with my car?

                  Did the video quit working, or am I not manly enough to make it work?


                  • #10
                    Re: Am I going to blow up with my car?

                    Just don't smoke and fill. LOL.