My mid pipe cracked right where it connects to the resonator. Would a muffler shop be able to weld it back together or should I just find a used midpipe? Also, is it okay to drive with just the headers for several days? Some people say its okay and others sayi can ruin the valves. Thanks in advance.

 

A good exhaust shop can fix it, and running just open header won't hurt anything.. ever seen a real race car?

 

You won't damage valves with open headers. It's 100% myth. Exhaust piping has a few purposes:

1) Route sound to the back of the car where it is quieter while in the car
2) Route exhaust gasses to the back, where it gets the least smoke on the car
3) Route HEAT away from the engine.

Number 3 is most important. If you run a car without any manifold or header, it will not route heat away from the head. The head will then get hot and valve damage, and much other damage, can result.

Think about dragsters...with a 3-4" open header that's ony about a foot long. It works just fine because it's enough to get heat away from the engine.

 

Running open headers on a car that is tuned for it is a little different than just running open headers when you are tuned for a full exhaust. It will cause you to run lean, which "can" damage valves.

 

What controls your amount of fuel into the cylinders? Not the velocity of exhaust, or backpressure.