I recently modified my 2006 5.4L with a K&N CAI and it went just fine. Following this I replaced the stock muffler with a bullet and had a local show run the exhaust out the rear. I'm pretty positive I've lost at least 1mpg since the exhaust modification. In looking at the bends that were made I'm wondering if the exhaust bends are my problem - seems pretty pinched. I'm considering going to a single flowmaster cat back system that is mandrel bent etc. I've attached a few pictures of the bends in question. What do you guys think about this? Really looking for any thoughts or advice. 1st post - thank you in advance.

F250 Exhaust - Home Inspections in Punta Gorda | Port Charlotte | North Port - Maggiore Inspections

 

Looks like identical bends to stock and my gibson exhaust.. have you been driving harder listening to the exhaust??

 

At first I thought it my be my foot but I decided to drive like a girl for a few tanks. Still poor gas mileage

 

Typical crappy exhaust shop bends, the reason why I do my own exhaust work with mandrel bend sections and mandrel bent catbacks. The muffler may be some of the culprit too. Is it possible the fuel in your area changed to an oxygenated winter blend or temps got colder?

Below is a pic of a a 3" pipe the local exhaust shop did. This was a shallow 30-35 degree bend. I cut it at the bend to show how much it collapsed. The bend turned the 3" OD pipe to less than 2 3/8". Not good for performance.



The bends on the Flowmaster catbacks are mandrel bent a smooth. I have the Force II kit on my truck now.

 

Thanks DKF. This was exactly the type of feedback I needed. Not the fuel since I'm down here in south Florida. That picture is great. I can only imagine what the inside of the bend looks like on my truck since it's closer to 60. I'll have to cut a cross section once I replace with a Force II kit. I take it that you're happy with the Force II? Any advice or tips on the install? Thanks again.

 

Both Force II catbacks I've installed were for 99'-04' SDs. The exhuast clamps that come with the kit are junk. My kit included a combined hanger/clamp that clamped the tailpipe to the mufffler outlet. That clamp/hanger is flimsey and tends to rust out fast. I made a new one out of 304 stanless rod and a stainless exhaust clamp. Buy some better aftermarket exhaust clamps. I've been using 304 stainless u-bolt clamps from Jegs but any quality clamp is fine. A shaft collar may be needed to help hold the talipipe hanger into the rubber mount on the truck. Since your in Florida rusting hangers and clamps isn't as much of a concern as it for me here in the northeast.