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Building bi-fuel Cavalier w/ 2 tanks... safe?

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  • Building bi-fuel Cavalier w/ 2 tanks... safe?

    Hi Guys,

    I'm going to do a bi-fuel conversion on my cavalier with a {removed by forum staff} kit. For tanks I currently have a single 3000psi Contour tank and will be picking up a second tomorrow evening. This should give me about 11GGE which is perfect for a couple days driving.

    My question is, I can put the first tank in the factory location behind the rear seat-back perpendicular to the direction the car travels. The second tank needs to go directly behind that parallel to the first. This puts the tank as close as it can possibly be the trunk lid.

    I've seen the abuse tests of these tanks and have to say, aside from armor piercing bullets and snapping the valve off, I feel pretty safe. It's just the proximity to the rear of the car with the second tank that has me a little concerned in a rear-end collision.

    Any thoughts?
    Last edited by Lakewood90712; 06-30-2008, 11:14 PM. Reason: reference to non certified kit manufacturer

  • #2
    Re: Building bi-fuel Cavalier w/ 2 tanks... safe?

    Well, there are MANY people that do it.

    This is my thoughts.

    If you are going to carry kids or other people in the back seat, it may NOT be best...if you did get rear-ended it could very well push both tanks right into the back of your passengers. I suppose that it could explode as well. That being said I have thought about fabricating a tough 3/8" thick piece of reinforced steel to fit right behind the rear seat that I could bolt into the car, so in the event this happened (especially an explosion) that reinforced steel would protect myself any anyone else in the car (or so is my thoughts).

    I am comfortable with one tank, but I am personally not with two. I feel much better with the spare tire and the extra collision space between the rear and the tank. I wish I had more milage (disconnected my fuel pressure sensor and I get to use the entire tank) than my one tank, but I am content.

    Good luck!


    • #3
      Re: Building bi-fuel Cavalier w/ 2 tanks... safe?

      Yes, second tank can be added to Cavalier bi-fuel. I helped friend take 2003 Cavalier bi-fuel to Tulsa Gas Tech in Oklahoma and add 4 gge tank in trunk. Now he has 10 gge total capacity but normally gets 8 gge at fast-fill when totally empty. Virtually no trunk left so spare tire donut goes in interior of car.

      Based on video tests I've seen and everyone I have talked to about cng, I WOULD FEEL SAFE in the event of a wreck, especially if rearended, since the cng fuel tanks would either stay intact (right where they are - - most likely), or possibly with most severe rear-end (say by semi truck), the tanks would become dis-lodged and release their fuel is safe manner through PRD (pressure relief device).

      Compare above to how you would fare in rear-end accident with normal gasoline vehicle like say a Pinto or Crown Vic - - - both of these had lawsuits for FIRES from gasoline burning when rear-ended. Imagine all that fuel spilling on your backseat occupants and burning them since Ford didn't design the gas tanks in those vehicles [email protected]@!!

      Any day, I would take cng over gasoline for safety . . . . any day!!


      • #4
        Re: Building bi-fuel Cavalier w/ 2 tanks... safe?

        Ssybert et al,

        The regulations governing aftermarket installations can be found in the NFPA Phamplet No. 52. Somewhere in there (don't make me look it up) there's a requirement that the cylinder mounting must have a backing plate (on the other side of the sheet metal) with a surface area of 7 sq. inches or more.

        The final assembly has to be able to withstand a force of 8X the weight of the full cylinder applied in any direction without moving more than one-half inch.

        So, this suggest a fairly substantial bracket (preferably from the cyl. mfg.). We cut 1/4 steel plates to form a base for bolting the brackets and then bolted the steel plate to the body. Worked pretty good and I've probably still got the drawings somewhere (don't make me...).

        Hope this helps and remember in real estate it's, 'location, etc.' In CNG installations it's, 'pressure, pressure pressure. Be sure to be safe!