• bestusername@aussie.zone
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    9 months ago

    There’s going to be a limit to how much pressure before stalling and/or damaging the engine, but it would inflate, and as the gases cooled, it would deflate somewhat.

    Exhaust jacks are used in 4x4 recovery, so an engine can lift a car, but they seem pretty limited and dangerous and I’ve only seen one used once in my ~25yrs off road.

    • XeroxCool@lemmy.world
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      9 months ago

      so an engine can lift a car

      Force = pressure x area

      It’s not that big of a feat. Using the very low estimate of 2.5psi from another comment about exhaust pressure, that means it can sustain 2.5 pounds(force) per square inch. To lift half a 5000lb suv the force needed would be 2500lbs. Rearrange the equation to [area = force/pressure] and it becomes [area = 2500lbs/2.5 lbs per square inch] so 1,000 square inches. Divide by 144square inches per square foot (12x12) and you get 6.94 square feet gives you 2500lbs of force from 2.5psi. Then to find that area from a circle, divide by pi and square root the result (rearranging area=pi*r^2 ) and you find that 2.5psi will lift the side of an SUV with a little less than a 3 foot diameter circle. That’s about the size of the lift bags I’ve seen.

      And all that while I’m thinking 2.5psi sounds low. Regardless, I doubt an exhaust system would handle anything close to tire pressure before popping off fittings. Plus mufflers have weep holes and fittings tend to leak anyway. They rely on the direction and speed of exhaust gas a fair amount.