Hello all,

Brand new to the boards and ford trucks. Glad to be here.

I've got an 88 Bronco with a 5.0L 302. Great truck but not-great gas mileage. As best I can tell it gets about 13 combined city/hiway. Unfortunately I changed jobs and my commute is almost an hour now. Gas prices what they are I can't afford to drive the truck to and from work everyday.

So on to my q's. Please bear with me, I'm not mechanically-inclined...

I'm wondering about ways to improve fuel-efficiency. I've read about exhaust systems, cold-air induction systems, fuel additives, fuel system cleaners, and even things "as seen on TV" like air twisters, fuel vaporizers, super conducters to line up hydrocarbon chains, and spark plug caps. Frankly, a lot of it sounds too good to be true

So I was wondering what, if anything, can be done to up those mpgs (other than sell the bronco and buy a hybrid ). Has anyone had good results with certain products or systems? I was hoping to get around 25 mpg out of the truck? Is that a pipe dream?

Thanks,
Moe

 

25 mpg not gonna happen. You should feel good to get 15+/-. Is the tranny a 3 speed or aod? IF its a three speed then an aod swap would help some as well as a tune up. Wouldn't recommend any aftermarket filter just install a new one every year or so depending on your environment weather its dusty or not. As far as any additive wouldn't use any, however a bottle of injector cleaner everyonce in a while couldn't hurt but probably doesn't help either. Good luck and time to save up for the hybrid. haha. later

 

JW hit that right on the button. My dad is still trying to get better than 14MPG with his 93 F-150 4X4 AOD 5.0L. I think there is not enough engine there to get decent efficiency. GT40P and some aftermarket heads are supposed to offer great improvements in power and mileage but you ain't gonna see no 25MPG.

 

13 combined is about right. You could waste $600 and more in typical aftermarket mods and get no financial return. $300 exaust systems, $200 air filter tubes and $150 ignition boxes may help add a little power way up on the tach. The "as seen on TV" junk is even worse.

Small gains may be realized at low cost by putting 75W-90 synthetic fluid in the rear diff and maybe a K&N drop-in air filter(that will let in more dirt than stock). Unload any junk that you carry around in it and air up the Tires. Oh, and keep a light foot on the gas pedal.

Jim

 

not to sound like an **** or anyhting but my dad usally sees about 17 combined out of his 91 van with EFI 302.....has the auto tranny with overdrive.....wish i could get more than 12 or 13 out of my 300 but that is why i am switching to 351w than i have power but no mpg..oh well can't win them all

 

my 93 f150 4x4 5.0 w/E4OD i can manage 18.5 on the highway with the cruise control. around town i get about 13-14mpg.

 

I think some things can be done to improve the gas mileage.

1 1/2" headers, or long tube headers would help. 2" exhaust pipes. 2 1/4" tail pipes. If you go too big with exhaust, you'll tune right out of the RPM range of your engine. When you get mufflers, make sure to get mis-matched mufflers. Mufflers that are the same are will drone.

Use synthetic motor oil. Don't use K&N, they don't help gas mileage.

Your engine will have a diagnostic port. I'd have the codes read to find out how everything is doing. It could be that your engine has been stuck in the 'limp home' mode and needs to have its EGR or HEGO fixed. BTW, the EGR helps fuel economy.

 

I hate to restate the obvious, but Broncos are heavy and 302s have to work pretty hard to move them. Even my dad's 98 F150 doesnt do much better than 16 hwy with the 4.6. With the money you would spend making your Bronco get better gas mileage, purchase a beater to get you to and from work and make a street demon or offroad monster out of your Bronco! My 351W 65 mustang gets 21-22 hwy with a T5 and 3.08 rear gears (if I keep my foot out of it). Mustangs are pretty light weight though. I have to commute with it almost every day.

 

Hi, I have a 1995 F150 and I just recently installed a K&N airfilter. I got a increase in mpg after that. My truck has the 300 and I used to get 300 maybe 310 miles to the tank, now im up to 330 or 350 depending on how I drive, so I know the K&N from my experience can help out that gas mileage.

 

That's incredible. Literally. You're getting a 10% increase in gas mileage by putting in a 'low restriction' air filter.

 

Yikes! I feel much better about the 13-14 mpg that I get with my 351w in a extended cab, long bed F250 4x4. Even with a camper loaded not in OD I get 9.
I did notice an increase in power and mileage with a Gibson cat back.

 

"If you go too big with exhaust, you'll tune right out of the RPM range of your engine."

What's considered too Big? What happens when you tune right of the RPM range?

 

If your exhaust system is too big you will lose the advantage of 'Heimholtz tuning'. With a properly sized exhaust system you get a low pressure wave in the exhaust ports when the exhaust valve opens and it helps evacuate the cylinder. That means lower pumping losses and better cylinder filling. More power and economy.

If the exhaust is too big, the back pressure might actually impede the evacuation of exhaust from the cylinder. Loss of power and economy.

How does it work? As you already know, sound waves are the vibration of air. Sound has a speed. The speed of sound varys because air varys.

The exhaust system resonates like a trombone resonates. If you lengthen the trombone, the resonance changes making a different sound. Tubas are big and make low notes, flutes are small and make high notes.

If you tune your exhaust system so that the note resonates just right, you can get the low part of the sound wave to be 'standing' at the exhaust ports when the exhaust valve is open. If you mis-tune the exhaust system, there could be a high pressure wave standing at the exhaust port.

There are some well known formulas for sizing the exhaust system.

Bottom line; bigger is not always better.

 

Is this setup bad:
3'' headers
stock Y-pipe
3''high flow cat,
3'' muffler

 

Flowmaster has some very good information on their website, it is basically a very simple quantification of what Paul said. It lists the ideal pipe size based on engine displacement, power level, and single or dual setup.

It's funny, most everybody you ask can give a fuel milage number, but I'm curious as to how each person's method of calculating their economy has to do with the numbers we're talking about. You can't just add up the miles from your last fillup and divide it by the amount of fuel it takes to fill it up for two reasons:

1) how many miles did you really go? Is your odometer correct? even changing the size of your tires will effect your true distance travelled. There are several methods for correcting your odometer. My preferred method is to go on a very long trip where you will be on an interstate for at least 100 miles. Write down the mile marker number and your odometer reading as you pass by. 100 miles later, write down the mile marker and odometer reading again. The mile markers are laid out by qualified surveyors, and will be accurate within .01 feet. Compare the distance from the mile markers to what your odometer says. This is not perfectly accurate, since lane changes and other non-linear movement will add a very very small distance to your trip, but this is still a very accurate method. I found my odometer to be off 6.4%.

2) How much fuel did it take to fill it up? Different fuel pumps shut off at different pressures, and filling up at different temperatures will also effect the shutoff point of the pump. This is almost impossible to correct, but it helps some to use the same pump every time, but that is far too inconvenient for what it's worth.

I keep a clipboard in truck, and every time I fill up, I write down the milage and how much fuel I added. This way you can take an average number, which more or less eliminates the gas station pump error. It's also a good idea to write down any maintenance that you do on that clipboard, so that you don't have to try and remember how many miles you have on that oil, that fuel filter, or those tires. TK