Before anyone says "Go read the other threads," i have searched for it and read like ten other threads that have anything about about gas mileage....

I have an 04 3.9, I was averaging 19-20 MPG. I was not driving anywhere near conservatively. Everything was fine untill I moved, now I'm putting 60 miles/day on my car about 70% HWY and 30% CTY/MTN... I started to drive a lot more conservatively and brought it up to about 24 MPG. At PFC pay in the army i can't afford to spend $200/mo on gas, so here is my question; Is there any way to improve my gas mileage to where it is worth keeping? At this rate by the end of the summer it will be traded in for a 2012 CR-Z....

Here is my idea thus far;
CAI, TB Spacer, Full exhaust, UD Pully, Flash tuner with 92octane conservative tune loaded (also a performance tune for the weekends).... Will this give me any kind of MPG gain? If so, how much? At what point do the upgrades start to require more fuel to support them?

 

I dont see where any of that will help. Buy the cheapest gas, clean the air filter, correctly pressure the tires.

 

CAI - 2-4 rwhp, no real MPG gains
TB Spacer - paperweight and scrap metal
Full Exhaust - 3-7 rwhp, minor mpg improvement
UD Pullies - 3 rwhp (maybe) extremely minor mpg improvement
Tuner - can net minor MPG improvement, no need for more than 87 octane, the rest is just wasting money

So with that out the way you need to attack why is your car getting such poor MPG. You should be averaging 22ish mpg and getting 26+ on all highway trips. You need to look into changing the plugs/wires/coil pack, properly inflating the tires, and run a scan to find any bad or faulty sensors. The tuner will help lean our the fuel a tad which Ford runs most their cars a little rich from the factory which isn't exactly needed, but it's not gonna make a huge improvement on it's own.

 

Daehawk
CAI delivers more/dencer air, the full exhaust frees up air flow out of the engine, letting it run more efficiently... the UDP creates less resistance and frees up some drag. Flash tuner changes the Air/Fuel ratio, and higher octain burns hotter producing more power and moving the car w/o having to use as much fuel...

jthorn9
3 miles of my trip is strait up the side of a mountain... just put double platinum plugs in, was considering getting low resistance wires and msd coil pack, and my tires are 35psi.... so 89 octane is better than 92-93?

 

You don't need anything more than 87 oct unless you are running a supercharger/turbocharger or Nitrous. Higher octane will just mean wasting more money per gallon when you fill up. You won't ever get improved MPG with it in this type of situation.

You driving style and the fact that you are in a hilly area is going to be the biggest factors to over come.

Weight is another issue. How much stuff do you have in the car? Big stereo? Tool box?

Like J posted...tune up the car. Plugs/wire/coil, fuel filter, airfilter, fuel injector cleaner, proper alignment on the front end, good tires (proper inflation). Those will be the things to do - not spend money on 'performance' parts. All those parts you listed are going to cost more than you'll save on gas.


Then get your foot out of the gas as much as possible.

 

+1

I have tuners for both of my Mustangs, each has 3 tunes on it, and you know what tune I run....the performance 87 octane tune. Why....because it's all my cars need as they're NA and running 93 vs 87 isn't going to yield more than a couple rwhp and next to nothing in the quarter mile.

As Roush stated quick looking at "performance" parts and just do a full tune up replacing with OEM factory components. All that other crap is just that crap, that drains your pocket book and offers no advantages over stock unless you're highly modified.

 

Do you have the title to your car? I fail to see how adding a payment for a crz will actually save you money,do a tune up and keep your car

 

Oh, and we all know what those mods are "spose" to do, but we all know too well what they REALLY do, and that's drain the wallet a little faster, trust us on this, all the the people that have responded have been there and done that. Roush and I have built several different engines in our day, and Roush helped design the first M112 supercharger assembly for the Essex 3.8L.

 

Most people dont realize that the higher the octane the harder it is to burn.

 

so the final verdict is full tune up (all filters, plugs/wires, coil pack, tire pressure) and run 87 octane for best gas mileage right now? the other stuff would just be for nominal HP gains?

And to answer mustangman, I am still making payments on my mustang.... still owe about 5g's on it, when its paid off the gas wont be as big of a problem.