Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

What would happen?

I have a question for you all. I was watching mythbusters a few months ago and they were seeing what would happen if you stuffed something up a car’s tailpipe. They found that it just shot the stuff out. However, they didn’t follow the myth all the way to its end like they usually do. So, What would happen if the pipes were say, welded shut or pinched off from a bent pipe?

Granted, this is assuming the car would not simply bust it’s muffler (say it had a full welded exh with glasspacks).

Would the engine simply stall? would it blow something?

My guess is it would kill the engine. No damage

same as a fully plugged cat. no start

In Tom’s & Ray’s words:

What would happen if you were able to inhale, but not allowed to exhale?
That is essentially the same thing that you are proposing for this car-based scenario.
In both cases, the test subject would die.

I remember when my friends stuffed two potatoes up the tailpipe of my first car, a 1974 Cadillac with a 500 cid V8. Not knowing what they’d done, I started the car like normal, didn’t notice anything unusual, and drove away. My friends were watching and said the car launched the potatoes, ricocheting off the steep driveway where they broke into pieces, some of which made it almost to the front door of the house across the street. It projected them with enough force that it made a visible mark on the asphalt driveway that persisted for many months.

I expect if they’d done a really good job, some joint in the exhaust would have blown out.

I was thinking that the preassure would become so great that it would bend a rod. based on the valve timing and such. More specificly, on a duel exhoust system (where one side could be driving the other side, even if the other side dies out).

It’d blow the exhaust pipes apart before it bent a rod.

The engine would simply stall because it couldn’t ingest new air and fuel because it couldn’t ehaust the spent fuel. Bending a rod would take a HUGE amount of force that the engine simply couldn’t run long enough to generate.

The pressure would stall the motor as the exhaust gas could not escape and combustion would no longer occur as fuel and air could not enter the cylinder.

Remember gas is compressible so it won’t “bend a rod”. However have some thing like water enter the cylinder and water it is not compressible will yield a bent rod like you talking about.

Pressure would quickly build in the exhaust system sufficient to stop the piston from being able to push the exhaust out. The engine would stall.

Since I cannot imagine there ever being greater force on the backside of the valves than on the frontside plus the force of the valvesprings, I cannot imagine any scenerio that would prevent the valves from closing and result in valve damage. The exhaust valve would close, but the pressure in the cylinder would still be high from the backpressure.