With the price of gas getting higher and higher most of us are thinking "damn i need some gas" about every 300-400 miles. I been looking around to see what are the max mpg's with some of these performance parts. I'll be getting a k&n air intake, a high flow cat, a magnaflow exhaust system, and a hypertech max e-con programmer. i dont drive with a lead foot or anything. so if you could tell me how many more mpgs i would get with all this. i get about 15 hwy now. thx

 

Maybe +1 mpg. You drive a truck, not a Prius.

 

15 highway is pretty good. i know people who would kill for that.

but gas has been dropping... not a big deal to me right now and i get 9mpg

 

how old is your catalytic converter and O2s? I was getting 10 city, then replaced my cat and two O2's and jumped up to 13.7 city.

maybe the tires are killing it. have you had your speedo adjusted to any mods?

I don't think those would do anything to increase your MPG. like I was telling motorbrreath, check the cat and O2, then look in to a good tune up (new distrib, wires, champion truck plugs or autolite..etc, going synthetic where you can, and going back to stock sized tires, then drive like your gas pedal only moves 1/4".

I am going to Maine next week, I will finally know my highway MPG. I will post in the MPG thread, its roughly 200 miles from here, so thats a little over half a tank (in city MPG)...

right now gas is $3.88 here.

 

In a nutshell? Not enough to offset the initial cost of the parts anytime soon. If money is the issue, I'd focus more on driving habits and less on parts.

 

Skip the K&N. Try the open element intake first (do a search for "FIPK No More"), some prefer the look and it gets just as much power, if not more. Don't go the CAI route unless you get one like mine (Volant) that sucks the air from outside the engine bay.

A Magnaflow high flow cat is what I'd recommend for that. Great upgrade. Magnaflow exhaust is good as well.

Hypertech isn't the best to go with, unless you get it cheap off of eBay or something. Go with Superchips, BFG, or SCT. More expensive, but they'll run circles around Hypertech.

I also suggest the Fastman throttle body upgrade. Its not a spacer (which don't work on our trucks, BTW), its a TB replacement. 52mm for the 5.9L, 50mm for the 5.2L.
[-The Fastman-]

I also suggest a good tune-up. New spark plug wires, new distributor cap and rotor, new spark plugs. For the wires, do a search, many opinions. MSDs are generally regarded as best though. For plugs, Champion Truck Plugs or Autolite 3923s seem to be the two most commonly recommended. For cap and rotor, anything brass.

I was pulling 9-10 mpg in town with my 5.9L when I was stock (I have a lead foot). After my upgrades (check sig for list), am now getting 11-12. Haven't seen enough highway miles to accurately tell, but last time I was out got around 14 mpg with a strong headwind.

 

Almost zero 'real gain' from those proposed part buys.

Because most 'daily driving' is done at part throttle
where both intake and exhaust flow CFM's are low
and at low cfm flow
the stock exhaust pipe & catalytic converter
don't create nearly any backpressure
probably less than 2 psi,
those proposed parts
will not give nearly any MPG increase,
unless the Hypertec max e-con programmer
leans the part throttle air to fuel ratio to something higher than 14.7
and I am 99% certain it does not
because you need a wide range O2 sensor
to hold a fixed AFR in the 16 to 20 range.

If you want to improve daily driving MPG:
change your driving habits to be more like a 'HyperMiler' (this is free),
lower your tire rolling resistance with more air psi (free)
or purchase new tire designs with lower coefficient of rolling resistance (cost about $500) which is kinda hard to do until the new government rating for rolling resistance get stamped on the tire sidewalls soon due to a new law.

For improved highway MPG
lower the drag your truck creates cutting through the wind
with better aerodynamics mods;
such as extending the air dam downward a few more inches with lawn edging (less than $50),
blocking off one third to half the grille opening (less than $10)
attach homemade vortex finders or commercial Airtabs ($20 to $80)
lower the suspension height ($50 to $400)
or buy a tonneau cover ($200 to $900).

Most of the aero gain from the tonneau cover is because it makes the the bed flush with during the last 3 feet before the tailgate. This is the critical area to streamline. About 80% of the aero gain of a cargo bed cover can be got more cheaply by putting a piece of plywood or foam board over this last 2 to 3 feet. You can also buy two cheap 'plastic tote boxes' of about 40 gallon size and secure them in the bed just in front of the tailgate. With the tote boxes you get some water resistant storage, and you can use them to hold sand or gravel for traction in winter too.

More aero tips from General Motors MPG guru Roger Clark,
as told to Popular Science magazine,
who used his tips in the real world to good effect to win a contest:

http://web.archive.org/web/200208032...332270,00.html

sample quote

HOW WE IMPROVED OUR TRUCK'S AERODYNAMICS

Roger Clark, GM's fuel economy guru, says these tweaks added at least 2 mpg to our gas mileage.

1. With no tonneau, plastic over the truck's bed smoothed airflow over the top.
2. By taping the grille, we improved airflow around the truck.
3. With no running boards, we blocked the gap between the body and frame rails.

 

well i have a 2500... it takes more power to push a heavier truck. I have 4.10 gearing so the tires are not the issue. The motor is pretty modded. I run full synthetics and royal purple oil.

 

You could also add an HHO generator for around $100-$300 bucks that should increase your mileage around 40-50%. Go on youtube and enter "hho generator" and "Stan Meyer" for more information. Basically they split water into its basic particles, one part oxygen - two parts hydrogen and the engine runs partly of the hydrogen gas produced, which in turn uses less fuel and increases mileage. There are a couple of simple modifications you will need as well with this system, o2 extender, Map/Maf adjuster, EFIE enhancer and posibbly an o2 adjuster for the gains to really be seen. You could also build your own circuits and generator if you are handy.

 

Or you could get one of these...
http://cgi.ebay.com/ebaymotors/REAL-...spagenameZWDVW

If its too good to be true, it is.