Hi, I am interested in getting a new exhaust for my car. I have an 87' Cadillac Coupe Deville V8 and I think it is 4.5 liters. I am still new to cars and wanted to know what kind of exhuast I should get and If it gives me better gas mileage. My friend suggested getting the "X" for better flow. Any help?
Your caddi doesn't have "true dual" exhaust from the factory...it y's down into one pipe, and depending on model and options may y-out to duals after the rear axle. Putting on and "X" pipe would mean that you would have true duals which would improve performance, but you might want to check state laws regarding emissions because it may not be legal in your state to convert to true duals. If it's not legal to convert to true duals, just have the pipe size increased one increment(ex.-from 2.0 to 2.25) where it is dual, then have the intermediate pipe(the pipe that will run from "Y" section to "Y" section)size increased by two increments(ex.-from 2.25 to 3.0). After 2.5", pipe sizes start going by half inches instead of quarter inches.