The Dodge Challenger Message Board

I have a 3 inch exhaust system with glass packs right now. The glass packs end right before the rear axle. This exhaust system is illegal in my state. So I have to buy a new one to make it street legal. I am trying to decide between 2 1/2 or 3 inch complete system. I hear with the 3 inch you do not get as much low end torque as with a 2 1/2 inch. Is this true? What are the advantages and disadvantages of each? The two companies I am choosing between are flowmaster with super 40s and dynomax which one is better sounding and has better performance? My challenger is going to be used for street and strip I don't know if that matters when choosing an exhaust system.

Well Thanks,
Chris

im a flowmaster man myself, i love flowmaster mufflers so much i'd even put them on my riding lawnmower if I could.

2.5 diameter is fine (and quieter) for a street/strip car running 12s or slower. You are right that bigger pipes will drop the low end torque. Pipe length and diameter over the whole system length is a science in itself.

If the engine is big and the power made at higher rpms then a 3-inch can make more power.

One theory is that pipe diameter should decrease as you move toward the rear of the car. This is to maintain gas pressure and speed as it looses temp running along the pipe. The faster exhaust gas moves in the pipe the more torque you will make at lower rpms as it scavenges the cylinders better.