Hi Bill, RPM's are Rpm's, at 60 I'm turning 1500 flat,at 2200,I'd have the cops swarming.The reason town driving get less mpg is up and down rpm's and recovering power so often.Even is the engine is running in neutral,it will naturally burn more gas at 2200rpm than at 1500rpm.You also have a thing for exhaust sound,which means you like to hear it,and it's a fact that guys with love of good sounding pipes tend to get in to it a little more,hence less mpg.Drop your ratio into the low 3'S,put 50psi in your tires,and wear ear plugs (HA-HA) and you may see some mpg.You have an automatic trans,let it worry about the hills,us guys with sticks have to think about it.I've had 2 300's,a '91 and now a '96,and if either one got your mileage,that baby would be down until it was right,both got 18-20 on the highway,the '96 is more towards 20.I've got 2:73's and p235x75R 15's,same Daytons you have, only smaller and a tonnea cover. The air pushes so hard on the rear 1/4 of it that I have to put the cross rib back in position after every trip.That plastic valance on the bottom of your front bumper is said to save 1 pmg,so if it's off,put it back on.Good luck with your mpg's,but I think your going to have to mess with gears.

 

I know your right about the noise buster. I definitely got on my last truck more after I redid the exhaust. I just loved the sound.

Do you run 50psi? I run 40psi all around and I'm thinking that 35 may be more appropriate for my truck's weight. That reminds me, Bill, have you considered going to something other than an M/T tire?

That valence is said to make that much of a difference? wow.

 

I don't think it will help any at all. I have experimented several different times over the years with leaving it down. It didn't matter what the conditions were, mpg never changed. I say just leave it on.

 

i did notice a difference when I removed the valence from the front bumper. I have since put it back. Like was posted before, your tires are definately not helping. All that extra rubber does make a difference. Maybe think about getting highway tires from spring through fall. Im sure the body lift isnt helping either, but thats the price of a nice looking truck. To be honest, the 4.9 in my first truck (wish i had pics to show everyone, it was really sweet) got horrible gas mileage. I loved the 302 in my retired DD. Everyone complains about them but it was perfectly suited to my F-150. you are just going to have to try different things. Leave the tailgate on and only buy a car as a last resort. Because if you do, you will miss your truck everytime you get in it. Can you really put a price on love?

 

A lower gear ratio like the 4.10s is going to increase your mileage around town over a higher ratio like 3.27s.

 

Tailgate up. Before I moved to the town I work in, I was commuting about 120 miles a day and had tried the tailgate trick (even though I had seen the Mythbusters episode). I got worse mileage, by about 2 MPG or so, with the gate down/off.

On the idea of a second car to save on fuel: Unless you're doing a lot of driving, it doesn't make financial sense. There's the price of the car, upkeep and repairs, and insurance. The DD car would have to either get stellar fuel mileage or be really cheap to justify its existence.

 

shoot i could be looking at 18mpg if i found a tailgate

 

I would think the same thing, and to some degree we are both correct. When I ran factory tires (27'' tall) with the 4.11, my around town power was nutz. I was the fastest thing around town in a full size pickup 6 cyl. My fuel mileage around town wasn't bad, either. It was when I put the 31's on the truck I noticed a big loss in power, almost like a brake was dragging.

My engine isn't in the best shape but it's not bad. I really should do a compression test and find out what the cylinders are doing. I know the engine bogs down a lot unless I run higher octane, which makes me think I have low compression in one or more. Plus my engine runs inconsistantly; some days she's a race truck but most days she's a tractor.

By the way, I think it's interesting people suggest I run a higher gear to keep the 300 in it's powerband.. It seems like mine pulls hard to 3,500 rpm. I manually downshifted the truck into second on a big hill yesterday and the truck really came alive, and I was pushing 3,000 rpm. Surprised me. From what people say, I would have more power at 2,000 rpm, not three.

Or is this simply all in the gears?

 

hey Buster, thanks a lot. I still have the valance. I almost took it off a while back but I'm glad I didn't now.





Yup, when I need tires I'm going to 30x9.5's in an A/T.

 

I totally agree that the air dam does help. I had mine off for a few years and putting it back on helps.

Hey Bill, Why do you want to go to 30 9.50 tires? With 4.10 gears your RPMs will be even higher. It won't help fuel economy at all. Besides it will look goofy since you got a body lift.

My fuel economy is the same with the 31 10.50s as it was with the 255 70 15s

 

The octane thing doesn't make sense to me. If you have low compression, then your truck should have less need for a higher octane fuel. I know what you mean about inconsistency though. My truck seems to act the same way.

I think it works like this. Peak torque may be at 2000 rpm, but peak hp is probably closer to 3000 rpm or maybe even 3500. Look at it this way, you may get X amount of power per revolution at 2000 rpm, and when you go up to 3000 rpm you have less than X power per revolution, but... There is a revolution every 1/50second (3000rpm) instead of every 1/33second (2000 rpm). This means that you still have more power per second, so to speak.

 

Skyfox, I run 40psi in mine,but if I were looking for every mpg,I'd jack it to 50 and sacrifice my aching back.I have seen the tread cupping on under inflated tires,so I try to keep close to mfger's suggested psi.You may regret lowering to 35 down the road,but find out what your tires are supposed to be at, might be just fine.

 

Question

Do you have vacuum Gauge? We been discussed that before.

My F250 got 16 mpg now. If I didn't have vacuum gauge I maybe got 11-12 mpg.

Vacuum gauge tell how much you push on gas and not ever moving fast enough.


You should try. When you approach to hill Don't push more gas just try keep little speed like road say 45 but try go before 48 then leave pedal only it will slow to 40 when climb hill when you go down on hill lift your foot off gas it will increase speed.

That how I got little mpg from do that.


or keep F150 and get Escort or geo that will help you much.

 

I think there is some mileage to be found, in a smaller, lighter, milder tire. Like you said, it felt like the brakes were dragging after the larger tire... Going from 31's to 30's won't be too drastic of a change, but better on road manners, etc should be noticable. I felt a difference(in a bad way) going from 31" Timberline LT's to 31" BFG AT's... Heavier tire for sure.

How are other components? Fuel filter, air filter, ignition stuff? Any codes? It should be running fine on 87 octane.

Forgive me if I missed it, but what kinda' of mileage are you getting? Is your speedometer accurate?

 

Well, it says 35 front and 40 rear on my truck's door sticker. But I'm sure that's for a loaded bed.



I suppose if it's unloaded then I would need less pressure. That's why I was thinking 35 all around. Match the rear to the front rather than run it up to 40 like I did on my last tire set. I had the inside tread wear out faster than the outside tread on my tires running 40 psi all around.