My truck has 170,000 miles on it. I have replaced the plugs, air filter, stock size tires, pcv value, and all of the oils. I haven't done the fuel filter. I have cleaned the air intake and done the seafoam treatment in the pcv.

I really would like to have an aftermarket exhaust, flowmaster and a dual exhaust. Would it really harm the truck that much? I have to go over a pass daily and I would like to have the extra getup.

I will do the 4 ounces of Lucas fuel system cleaner, and the 42 psi with the tires. I think I was at 37 psi.

If I can get 18 to 20mpg, I would be happy.

 

I'm going to be quite honest here so I apologize if I sound offensive.

You are very unlikely to hit 18-20 mpg the new trucks are only just making that mark and that is with a 2x4 stripper model probably with the right set of gears and tires to boot.
These old trucks on a good day seem to hit 16 maybe in rare cases 17 mpg but anything beyond that is mostly coasting downhill with the transmission in neutral.

Now on to things that might or might not improve MPG if you went absolutely all out.

• Lower the truck
• Get a body kit and maybe a bed cap or at least a hard tonneau cover.
• Get narrow Low Rolling Resistance tires
• Find the lightest weight wheels you can get.
• Consider gutting the interior
• Electric fans
• Have only one bucket seat for you.
• Replace all glass windows with light weight substitutes like polycarbonate.
• Replace as many body panels with light weight aluminum or if available Carbon Fiber.
• Get the differential geared for your type of terrain which from what you have said about a mountain pass then a deeper gearing would be helpful.
• Be on the look out for any place else on the truck to shed weight like light weight drive shafts, suspension parts or on the very extreme end replacing the cast iron engine block with an aluminum block.

By doing all of the above you can probably hit the mileage that you want and then some but by the time you finish paying for this you could have bought a Mustang or Focus or Fiesta that can hit 20+ mpg.

In short I agree with whats been said before that you should save your money in the long run.

 

Very cool. I'll be happy with 16mpg, lol.

 

I am considering a muffler change on mine and don't feel that it will cause any problem if sized properly.
I forgot to mention that I replaced the stock airfilter with a K&N and changed the intake pipe between the fender and airfilter housing to 3 inch pvc.
The mere mention of K&N stirs up the purists however, I am well pleased with it.
In most cases, the disgruntled are the ones who don't properly maintain it.

 

What do you consider a proper size for a muffler?

 

So far I don't think Peter is going to listen.
He needs to spend his money and find out there is little return for the expenduture and effort after it has been explained in above replies.
Good luck.
Merry XMAS. Santa will be coming but he will 'take back' what he 'brought you' last year if yer not good!

 

Tell that to my engine. I've lost an engine to a K&N filter. Not making that mistake again. Besides, why would I spend that much money on a filter when I can get a much better AFE washable dry filter for less.

Do air filter increase mileage or performance though? On a stock motor, no.



On the muffler, all a Slowmaster is gonna do for you is make the truck noisier. And like mentioned above, how do you define properly sized, Slowmasters are all the same size inside. A straight through muffler is a better bet. My experience with high flow mufflers and gas mileage? Nothing encouraging. Not saying a performance muffler is a waste of money, I'm saying you shouldn't count on it to affect mileage in a positive way.

If you want to get better gas mileage, get a more fuel efficient ride. Trying to get a V8 F150 to get 20 mpg is achieveable, but as mentioned above, the truck wouldn't even be nice anymore. and it would likely cost more than the fuel savings.

 

I am not changing the muffler to save on fuel, I know that. I want to change the muffler for the sound and maybe a little power pickup if any power pickup. That's all.

I know that I won't make any gains with the MPG with the truck, that's cool.

 

In order to maintain your current power , just do a cat-back.Do not touch your cats, leave them stock! Get one muffler with single in and dual out if ya want the looks of duals. Stay with 2.25 or 2.5" pipe.
Go on youtube and search different setups to decide what sounds good to you. Everyone sound preference is different. Some like loud , some like just a little louder then stock.
Your mileage will go down for a wile.Mostly because you like loud (I do too) and you'll be on the gas more in order to hear it.
Hopefully you will get used to the sound after a wile and start driving it normally. Then you'll be right where you are now as for mileage and power.
It will sound good to you but will not give you any power!

 

Yeah, I won't touch the cats. I am coming over from the import tuner world so I do applogize, lol. I am now a homeowner but the Hyundai Tiburon just couldn't carry the wood like the F-150 can, lol.I'll do the dual cat back system, I just want the sound and the looks of the system. Maybe a 2.5.Has anyone done any dyno's on the trucks to see if the mods have actually done any HP gain's? Yeah, I just bought the truck like 3 months ago. It was a company truck, the 4.6 Triton. Was is the difference with the Triton engine? Also, I just did my MPG this morning, I got 16.40, that's good.Sorry for the formatting, typing this on my work computer.

 

My real truck is 87 f250 4x4 6.9 stock with dump bed being rebuilt so bought 97 f150 4x4 4.6 w/flow master and k&n intake, returned to ford OEM exhaust and intake, shocked that mpg rose by 1.25.
I do agree flow master sounds nice but not worth it.
If you want mileage go diesel my 87 gets 19-22 mpg loaded gvw 10,000 lbs empty 22-24

 

Ive got a solid axled 97 f150 on 40 inch bias ply tires. I still manage to get bout 14mpg. Ive got a cold air intake, dual 3 inch Exhaust and I guess the biggest factor being an npi block with pi heads and intake all freshly rebuilt. Stock 97 ecu. It'll use up a whole lotta gas when asked to but when the added power is used properly its quite efficient (for a lifted truck).

 

I had a 1995 Dodge Ram with the 5.9 MPFI engine. I put on a K&N air filter, Magnaflow mandrel mandrel bent exhaust, free flow catalytic converter with a Flowmaster muffler. It got no better gas mileage, but had more power as it was breathing easier. the best I ever did was 18 mpg. (it sounded AWESOME but not stupid loud)

You could take the bed and the cab off your truck, just drive it in the seat, and still not get 20 mpg. It is a truck, with a truck tranny, and truck gears.

 

Change the spark plugs often, run hard tires, don't use AC unless you really need it, be light footed and don't carry extra weight you don't need.
It's about the best you will do.
I have been able to get as high 17 mpg by controlled driving intentionally and watching a digital MPG indicator but that is not an average but only over a time and distance run that I repeat very often.
The road terrain also makes a huge difference as does the temperatures.
An average overall is quite different.
How it's calculated can be from tank fill to fill, day to day, an average of tank fills etc. where conditions can change.
So the bottom line is what does it mean?
You have to accept the range you get.
The truck has a certain running weight, is controlled by a computer program and it's hardware and basically fixed for fuel to power it on an average overall basis.
Exhaust and intake changes make little difference to a controlled system.
You can't force these changes on the system because it will just result is system readjustment that negate the effects of the changes everywhere except maybe wide open throttle where you do not run most of the time.
Good luck.

 

I have a 1997 f150, 4x4, 4.6, pushing 170,000,,added the dread K/n filter,, haha,, an aero turbine muffler, 70 mph , getting an honest 19+ on highway, I can live with that, and it sounds great too, my 2 cents, 3.55. open gear's, 265,16 tires