If we block one tailpipe in a twin tailpipe muffler, will that increase the power and acceleration of the car?

Most Likely answer:

1) after your mechanic made changes to your exhaust it increased the airflow through your engine. This being done, now your air / fuel mixture measurement is off in the engine computer. This happens often when aif flows are changed due to exhaust or intake changes.

To fix:

Unhook car battery for about 30 minutes, then reconnect battery. This will reboot the cars computer and auto reset your air / fuel mixture and idle speed. Increasing your torque and HP to a level even higher than they were before given the freer flowing exhaust.

If Not:

your idea might restrict too much exhaust, you may make too much back pressure and cause damage to your engine. You can easily burn up an O2 sensor, exhaust gasket, catalytic converter, or bend and exhaust valve. Check that your mechanic properly welded or clamped your new exhaust system. He may have left a gap or leak causing your loss.

If you are going to attempt:

Do Not use wood! will possibly burn, instead go to the hardware store or Walmart and get metal tape. Made of a thick aluminum type tin that bends and sticks easily like duct tape. It is usually used for duct work on furnaces and air units in your basement, attic, and walls. (This can also be used for wrapping weld points, gaps or leaks at low cost until repairs can be permanently made.

Not at all. A tailpipe muffler is just a way to make your car make a different sound. No offense on this but for the most part it just looks stupid. If you are trying to improve hp, try a simple intake change or even a performance exhaust. Much better ways to spend the money then a tailpipe muffler. A lot of people have bought them and actually done more damage then anything else to the vehicle. for example melting the plastic on the bumper.

More airflow generally gives MORE power, so either it's all in your head or there is something else that got messed up during the installation of the new exhaust. Did you remember to reinstall the 02 sensors? If I'm not mistaken, 4-stroke motors need a little bit of backpressure to run properly, but I don't think too little pressure could be an issue if you still have a full exhaust. Also, if you changed out more than just the mufflers (installed headers) than you would want a re-tune after that if your cars running crappy.

So, basically, no. Although, if your car needs to be tuned I suppose it could possibly help under odd circumstances, but very unlikely.

Wood will burn, if the car has a turbo, you may have changed things,

Not at all

No, it'll be even worse.

no dont do it

?! No.