I just bought a 01 Supercrew 4.6L 4x2. I am thinking about putting down some money and installing a Borla cat back. I know the HP numbers, but i don't have any tested numbers on improved fuel economy. I have a Holley "hi-flow" filter to let it breathe a little better and will have a ARE tonneau installed this weekend, so both should help. Just wondering if anybody out there knows what percentage increase (if any) I will get. All the articles i read, talk about HP increases...and tone......but leave out milage........so any positive info will help make up my mind. Lie to me if you have to........truck is too damn quiet.

 

I'm also interested in mileage. Everyone has said that the mileage stays the same because you keep your foot more mashed down on the pedal!
A hard bed lid by itself will increase mileage by 2 MPG. I saw a college study on it once.

 

Watch the diameter of the pipes and you will gain mileage with free flow exhaust--go with big pipe and you will lose bottom end and gain top end---all dependednt on the size of pipe and muffler...

a low restriction muffler and same size or one size bigger pipe will work wonders for you....

dont look at hp numbers if you are looking for fuel mileage increases...

look at the rpm of the peak torque..this is where the best mileage is going to be...

if milegae is what you are after then dont lose your bottom end and dont build your top end....

 

I have seen no gain with an exhaust system, air filter, and bed lid installed. 2mpg with a lid is a dream. I think my problem with the exhaust is that I'm a little heavier on the foot now cause the true duals sound so good. Last tank of mixed driving was 16.5mpg. Oh well, I knew it would be worse than my Dakota. Want to play, got to pay.

 

The week that I picked up my SCrew, the first tank of gas gave me 17 MPG. I said, Huumph, this works. Well that was then, and this is now. Gibson model 9504 Dual exhaust, AirAid FIPK, and SnugLid bed cover, and the MPG is 15.

NOTHING improved gas mileage! The only product that helped
was the AirAid, gave me much more throttle response.

I know your gunna say I'm driving harder, AAAAAAAAA,
Wrong answer, for anyone familiar with the Smith System of Driving, Get the big picture, anticipate everything, stale green lights, etc. You'd know our goal is to keep moving, just keep moving at a constant speed. Anticipate the change of the light two blocks away, anticipate the person braking in front of you, choose the lane of least resistance, etc.

I drive easy, and on a recent trip to CA, on the expressway, at speeds between 75-85, averaged 15.7 (pitiful) was expecting 18.

 

Smith System of Driving?

All Good Kids Like Milk.

You're showing your age!!!

LOL!

By any chance, were any of your former "trucks" big and painted BROWN?

 

Can also say that adding a lid did very little if anything to increase mileage. Don't forget the average fiberglass "lid" weighs around 100 pounds. This may seem minimal but is a factor. Although I am somewhat dissapointed that I haven't experienced better MPG, I really like the looks of the lid on my SCrew!