Do Flowmaster exhausts hurt gas mileage?

Question

I have a 2000 V6 Camaro and want to put in Flowmasters. Would that hurt my gas mileage?

Answer 1

Yes it does lessen gas mileage, trust me. When I got flowmasters professionally installed into my car I drove the same way as I usually do and it really lowered my gas mileage by alot. Then I put in glasspacks and my gas mileage improved. The way(Flowmasters) are designed are to trap alot of air inside the muffler to create a loud sound but sacrificing performance/gas. If you ever open a flowmaster there are tons of chambers and mini walls that are created to constrict air from coming outside. From mechanics advise and to a personal experience....Flowmaster do lessen gas mileage by a ton but they do sound nice.