Im looking to get better mpg from my 99 5.4 scab with 3.73 gears. Curious to see what you guys have for tunes, intake and exhaust for the best result without sacrificing power.

 

E fans will be your best bet. And good maintenance. I think most see 1-2mpg from E fans if I remember correctly. Exhaust and tune may help a little. Gotts mod is free and has little gains.

 

What cfm should I be looking for?

 

Depends where your pockets are.. Some are confident in the mark VIII fans and claims are that they flow better than almost all aftermarket fans....which you can pick up at a junk yard for around $40. But they need a proper controller to run them. Most are using dc controllers I believe because that fan has such a high current draw. There are lots of topics on them. That is my plan, mark VIII fan and DC controller when I get the time. Most will tell you that is your best upgrade, fuel mileage, throttle response and a hp gain you can feel. BTW, I have the same truck.. 99 5.4L w/ 3:73's running 33x12.5x17's and seeing around 14-15mpg right now. Hoping for 16 with the E fans. I have been running the gotts mod on both this and my last truck, good improvement for the $6 it costs to put it together.

 

Keep up on maintenance, tires properly inflated and keep your foot out of the go pedal. OR the best mpg mod I have EVER done........ Buy a 4 banger car to drive around

 

The best, and only logical reply yet. Sorry, you have a heavy truck. You are not going to see leaps and bounds in fuel mileage savings no matter what you do. One thing usually negates the other...e-fans will be such a performance upgrade that you'll end up driving more aggressively because of the new found fun factor; thus washing out the fuel savings you tried to find.

Seriously though...I don't mean to be negative about the subject, you just need to be realistic about what you're doing. Don't do mods simply for fuel mileage, period! Why?? You'll never get a return on your investment. The cost of the mods are so significant in relation to any measly fuel savings you'll see that you'll never break even financially. So, do the mods because you like modding your truck. If all you're after is fuel "savings", from a financial standpoint you're better off doing nothing and concentrating on what was said about driving habits, tire psi, and things of that nature.

 

Ya i know its a heavy truck, and i want to mod it mostly need a reason to tell the wife why im spending money haha thanx guys!

 

Regular maintenance is about the best thing you could do. An exhaust and e fans netted me about 3 mpg gain at best. That is offset by aging parts so the gains often aren't noticed. These trucks despite age do pretty good mileage on the highways, anything else, nope! These guys^ are right! I did notice gains with a tuned chip, but had to yank it. Running premium gas hurt the wallet but seemed to keep the engine clean, so.....

 

You even helped me make my point. Any mileage increase you may have seen was negated by the premium requirement. Heck, yours isn't even a wash...you went in the hole But, you didn't do it for that reason

 

Even my 4.2 gets what I consider to be crappy mileage, but doing anything to try to improve it has too long a payback time. I can afford the gas, so I don't worry. If I really cared or needed better mileage, I'd buy a car.

 

Efans
Tune
Intake
exhaust
Gears
Lighter/smaller tires
New spark plugs might help if old ones are bad
O2 sensors should be replaced at 100,000 miles
Keep up on fuel and air filters
monitor your tire pressure, too much will wear out your tires sooner, too little will hurt mileage

Pretty much most mods will help mpg slightly. And of course maintenance will help too, the biggest gain I saw was from replacing my O2 sensors. Look up how to check tire pressure with chalk for the proper way to get the perfect PSI for your tires.

 

i recommend this:

300lb payload FTW!

 

06yz250f, thats it im selling everything to get one!

azmidget91, what kind of exhaust? larger than stock, headers, high flow cats and muffler, intake and tuner types? thats the kind of info im looking for, I know im not going to gain much but everything helps and im curious about the combinations you guys have.

 

OBX long tube headers are top quality. stock diameter on the exhaust is perfectly fine, no need for anything bigger than 2.5". x over and true duals will yield the best results. Mufflers... flow through design are best, no chambers. Magnaflow is preferred. Intake.. gotts mod or a true cold air system, volant? not to familiar with them. Dry element filters (non oiled). Check the tuner section for preferred tuners. E fans, LT headers, x pipe, true duals and a tune can probably see what... 10-40hp gains and 1-3mpg? For the cost of .. ooO I dunno, 2,500 bucks. Throw some gears in there and your at 4k.

 

Whats the difference between longtube and shorties? Besides the obvious..