Ok, so here‘s the deal. I‘m installing a new muffler on my car.The pipe leading to the muffler is 2 1/4 in diameter, or at least a little bit smaller. So do I need a 2 1/4 muffler inlet to fit on it? Or 2 1/2?Same for the exhaust tip, does the exhaust need to be 2 1/4 on a 2 1/4 muffler, or bigger?Answers for weld on and clamp on are appreciated.
The inlet should be 2 1/2 same on the tips. I would weld the exhaust in place if you have one.
You have to take into consideration, the horsepower and volumetric efficiency of your motor, and back pressure requirements. The larger you go, the less velocity of exhaust and back pressure. You need to find out how many cubic cc's of air your intake can utilize, and then the same of your exaust, to see how many cc's it can flow out. That will give you your volumetric efficiency % That will tell you to go larger or smaller, it's minor, but it makes a difference for the life of your powerplant.
The answer for your question has two parts. First, the inlet size you want is 2 1/4 inch. The exhaust size is really up to you. Exampleyou can buy a muffler with a 2 1/4 inch inlet and a 3 inch outlet and have 3 inch exhaust pipe to the rear of your car. Why do that you ask? What is a internal combustion engine but a big air pump, the faster you get the air into the intake and the faster you get it out the exhaust the faster your car will go. I suggest if you are putting exhaust on a performance car you do as listed above and use a Flowmaster 44, you wont be disappointed. If its going on a regular car inlet 2 1/4 exhaust 2 1/2.
