What Doesn’t Work

[Dave Whitmer]

Some folks are happy with their MPG, some aren’t. Those that drive a lot have good reason to look to improve MPG while maintaining the utility of their pickup.

Over the years I’ve noted some things that patently do not help.

1. Snake oil Lubricants and fuel additives do not measurably improve MPG They may make it run smoother or quieter but that doesn’t noticeably change the overall fuel consumption.
2. Bigger tires always reduce MPG
3. Commercially available tuners. Those work by increasing fuel flow. Generally that means lower MPG. Tuners make the truck more fun to drive, but flow too much fuel to do anything but reduce MPG.
I’ve had two premier tuners give it try for me. Believe me if somebody has a noticeable improvement (+1.0 MPG or better), I’m INTERESTED. Both of them managed to improve my MPG by 0.5-0.75 MPG.
I do think that for a few guys with egregiously bad MPG (10 MPG or less on a configuration that should get better) they may have a ECM problem that a commercial tuner may help, but for the guy or gal getting 14-17 MPG … don’t kid yourself.
4. Propane or other auxiliary fuels. For a while there was propane available in some places that was cheaper on a $/MMBTU basis than No. 2. Propane fooled guys who only looked at their No. 2 usage, but unless you can get free propane (Where can I get some?) it still a fuel you have to buy. It’s an auxiliary fuel, not a catalyst. Same with methanol.
5. Free-flowing intakes and exhaust. I have both. Neither did diddly.
6. Fresh fuel and air filters. Diesels run with considerable “excess air.” A little less doesn’t change anything.

[Delox]

I agree with everything, especially when it comes to your statements about placebo's, however I am forced to argue with #2.

Now I'll admit I haven't done tons of driving with the new tires, but I have so far been thoroughly surprised by my consumption.

1997 F-350 PSD shoved under a Bronco (4.10:1 final drive ratio)

Old Setup: Stock wheels/tires (~31.72" tall)
New Setup: 37" Wrangler MT and humvee wheels with magnesium beadlocks

I was seeing ~16.25 mpg with about 2000 miles of data, and am now seeing (after all required conversions, of course) ~16.33 mpg with about 500 miles of data.

Now I'm not touting about an amazing increase, but I am now capable of traveling at normal highway speeds for my area (~70-80 mph) without shooting far about 2000 rpm. Where as before I could only travel around 55-60mph before creeping above the 2krpm line. When I would try to travel at normal speeds (70-80mph) with the old tires I would see about 13-14mpg.

So, without a decrease in MPG, I added much larger tires, and am now more highway capable. I would assume if I traveled at my old speed of 55-60mph (which would translate to around 1700 rpm now, if I had to guess) I would presume I would see a slight bump in MPG. Maybe I'll give it a try, just to bust your balls

[SD26]

Originally Posted by Delox

I agree with everything, especially when it comes to your statements about placebo's, however I am forced to argue with #2.

I can give supporting data for number 2#.

I had an E350 bus with 225/75R16 tires and a 4:10 gear ratio. I moved into 235/85R16 tires to reduce my RPM's at the same speed. I probably had 25k+ on the first set up, and then many more thousands on the second set up with larger tires. I lost MPG. I lost in my regular running average MPG, I lost in my best MPG, I lost in my lowest MPG. I even lost in that my new tires cost more than the replacements that I could have bought in the original size.

I wanted to reinvent the wheel, but I still couldn't achieve it.

[Delox]

Oh I wasn't by any means trying to say that larger tires would always help MPG. I was simply disagreeing with the fact that he said it would always (key word being always) hurt mpg.

No doubt that it can be worse in some/many (probably even most) situations.

[CSIPSD]

Dave,

Ever tinkered with water injection? Just plain and simple water?

[stoker04]

So what does work?

[Dave Whitmer]

What does work?

See the sticky thread entitled "Improving MPG." That is all stuff I know works.

No, I've never monkeyed with water injection because I don't see how it would improve MPG.

But if you want to do a test with consistent measurements, I'd like to see the results.

[meatmachineman]

Just looking at #3. Glad "generally" was mentioned. I have an 04 I bought last year that had some plus 1 sized Michelins when I bought it. I replaced them with stock sized BFGs and my MPG tanked from 15-16 to 12.1. (I would argue point #2, but I went to a completely different style of tire, however, I believe driving conditions can factor into caveats for #2). I installed an Edge Evolution in hopes of getting some the MPGs back. I've been averaging about 13.2 with it. Not as much as I'd hoped, but certainly enough to make it's purchase worth it. Hindsight being what it is, I should have just bought another set of those Michelins. What off-roading I do is not very rigorous.

[txswampdonkey]

i have a 97 psd pretty much stock i did the tymar conversion went from 285s to 315s full 3" from turbo back with water meth. completely stock with the 285s 16-18 after i changed everything 16-18. and yes i had ford re calibrate my speedo, and even checked it with gps mileage to gallons used

[centerfitt]

While I do agree with the statements, im not sure that I agree with number 3. I have seen an increase with MPG after I installed a PHP Phoenix 6 pos. chip. Now im not sure if its due to the chip or if its due to the way I drive, but I did see an increase after installing the chip. Just thought I would throw out what I have seen.
Before I was getting about 18 hwy and about 12-13 mixed, now I am seeing around 22 hwy and about 15 mixed. While that does not seem like much, but for a heavy 7.3 i think thats really good, correct me if I am wrong.