So after doing some research on headers I decided to pull the trigger and get a set of JBA Shorty Cat4wards. Install was a pain in the a**. I fought for the longest time to get a good seal on the midpipe connection. Nonetheless, after getting it all sealed up with RTV high temp gasket, I can't get better than ~15L/100km (~15.5mpg) for mileage on my daily highway commute (110km/h highway speed). Where before the headers I was getting ~11L/100km (~21mpg). Is it normal for headers to be that detrimental to fuel economy? I've reset my PCM after the install but that hasn't helped. Do I need to replace the O2 sensors or is it possible that they are poisoned?

What's your thoughts?

 

Pretty rare to ever boost MPG`s with add-on`s. Usually you go backwards in MPG just like you did.

 

I found an improvement with my JBA Headers and Exhaust.

Next up is a custom Tune from Hemi Fever

 

I found a slight improvement with my Jba's, but i also went with a custom tune ,and true duals, and im very pleased with the power gain as well; I also had a hell of a time getting that mid-pipe seal, plenty of that high heat copper permatex did the trick.

 

Driving habits are usually a key factor.

 

I had a hell of a time installing the JBA headers, and definitely wouldn't do it again.
I am kicking myself for not going with Long Tubes.
I definitely have a leak, but thats due to a bad weld on JBA's part.

I drive the same route to work, and with my heavy winter tires/rims on (20lbs heavier then stock) I managed to obtain better gas mileage

 

I Agree Talon, that seal was a mother@#$@#r, in short, i should have went with the American Racing long tubes with their cats and all, but i was afraid to lose the factory cats, even though my dealer is really cool, you never know, if i was to have some sort of engine failure , somewhere else, then i might get screwed with the lifetime powertrain.Im not a know it all, but that permatex copperseal worked for me, i just had to let it sit , cold, for about 4 hours after i sealed it, and the leak was gone.Just curious Talon, was it the drivers side that gave you the hard time?

 

Driverside was a bitch! I fought with one bolt (install) for about an hour, it was the top right behind one of the bends.

If I can scrum up the money I will get Stainless Works Longtubes w/ Cat-less Y pipe

 

Just wanted to bump this.
Best MPG prior to the JBAs was 20.56mpg all highway up to camp and back.

MPG directly after JBA headers and catback. w/ 4 adults, luggage, sand bags, heavy winter tires.
100% highway, filled prior to leaving I got 19.10mpg.

Rotation previous to this was 16.8mpg

Truck just rolled 10,000km. Drive the same route up to camp.

 

I don’t have headers yet, but every time I changed something on my truck (i.e. spark plugs, cai, exhaust) it ran like crap for several days after the install. I would disconnect the battery to reset the pcm, but it still ran rough (hesitation, rough idle, crappy mpgs). It would take about a week for my truck to smooth out and run correctly, so your problem might change after a few days. It could be that your computer is still learning the new parameters created by your headers.