Crazy ideas for improving fuel economy...anyone gone THIS far?

[KevinsOffroad]

Hi all. Let me first state, I'm a little misguided sometimes, and sometimes find pleasure in doing things the hard way, for no apparent reason, normally.

That said, I'm exploring ways in which to improve the fuel economy of my 7.3L. Here are some half-****ed thoughts, in no particular order:

1) Going to taller tires (one gear ratio taller) to experiement with lower RPMs, and then deciding whether or not to go to a 3.54 or lower ratio, if one exists. My theory is that with the Edge Juice, I can run it in Economy or Tow mode, keep the fuel curve light, and keep the RPMs down so that I get better mileage. Here are the details:
o I drive about 6 miles to/from work, normally around 55mph average. Stop and go is only three or four times during a one-way trip.
o I'm getting about 17mpg currently, with the pattern above
o I will tow a trailer several times a year...5k-7k lbs worth. I'm not a leadfoot, so I don't mind slowing down when going up hill, if necessary (due to the ratio being too high, having to shift into 3rd gear).

**Has anyone gone to a higher ratio (lower numerically) and found an increase in fuel economy? Bear in mind, adjusted numbers (including the change on the odometer).

2) Installing a manual transmission. I know...crazy. I'd probably never be able to make up the cost of the swap with the difference in fuel economy savings, but it would be cool to have a 6sp tranny for towing purposes, as well as improved fuel economy. Again, refer to the first paragraph...sometimes a "long way around a short problem" kind of guy.

o Has anyone ever done this successfully? What about in a 2wd Excursion? Any differences versus the pickup that I should be aware of? Feedback?

o What would a swap cost me? I figure a net of around $3-4k after selling off the auto tranny, which is still in good shape. I have a shop, and a hoist, so labor is not a concern.

So, those are my crazy ideas. What do you guys think? Feel free to berate me publicly, LOL, but bring facts, not just your feelings when you do. I'm here to learn.

Thanks,
Kevin

 

[threejacks]

How many miles do you drive in a year? $3-4000 will buy a lot of fuel, plus you still have all the performance.

 

[95_stroker]

Here is a really crazy idea I tried last month. I left my house 10-15 minutes earlier and drove 10 miles an hour slower. My mileage went from 16.5-17.5 up to 20.5-21.5 and it didnt cost me a dime.......................




Food for thought.

 

[Hoss 350]

Hi all. Let me first state, I'm a little misguided sometimes, and sometimes find pleasure in doing things the hard way, for no apparent reason, normally.

Understood.

That said, I'm exploring ways in which to improve the fuel economy of my 7.3L. Here are some half-****ed thoughts, in no particular order:

1) Going to taller tires (one gear ratio taller) to experiement with lower RPMs, and then deciding whether or not to go to a 3.54 or lower ratio, if one exists.

Taller tires will NOT improve fuel economy. Making the leading edge of your vehicle that much bigger by raising it up with taller tires will counteract any benefit in lowered RPMs and then some. Your fuel economy will go down. I promise...

My theory is that with the Edge Juice, I can run it in Economy or Tow mode, keep the fuel curve light, and keep the RPMs down so that I get better mileage. Here are the details:

Good plan. The best way to lower your RPMs is to slow down, not put bigger tires on it. This also reduces wind resistance, and therefore increases efficiency. However, i have found with my J/A the best fuel economy is typically in the 3 or 4 range. Dunno why, it just is. I think it would be best in 5, but I can't keep my foot out of it in 5, so my economy always goes down

o I drive about 6 miles to/from work, normally around 55mph average. Stop and go is only three or four times during a one-way trip.

55 mph is about as efficient a speed as there is in one of these things. Good man...

o I'm getting about 17mpg currently, with the pattern above

You probably will do no better than that. YOur Ex has the aerodynamic capabilities of a brick, you should feel lucky you're getting 17.

o I will tow a trailer several times a year...5k-7k lbs worth. I'm not a leadfoot, so I don't mind slowing down when going up hill, if necessary (due to the ratio being too high, having to shift into 3rd gear).

My HO on this is if you have 5-7K behind you, you ought to be shifting into third on hills, anyway, even if you have the power to hold OD. It is better for everything to have some RPMs under the hood. Keeps EGTs cooler, keeps tranny cooler, puts more HP and torque to the wheels so the engine doesn't work so hard. If you do put a higher ratio in it, you'd better be in third every time, IMHO

**Has anyone gone to a higher ratio (lower numerically) and found an increase in fuel economy? Bear in mind, adjusted numbers (including the change on the odometer).

A gentleman named Dave Whitmer has put 3.08 gears in his PSD pickup, and lowered it (NOT RAISED IT!!!) with shorter tires and lowering kit. Has a custom FE burned chip, 6-spd manual, and some goofy-a$$ toneau cover that goes fromt eh top of the cab to the top of the tailgate, like a fastback. He has gotten 25 MPG. But his truck is 2 wd, a hell of a lot lighter than your X, manual trans, etc, etc, etc.

2) Installing a manual transmission. I know...crazy. I'd probably never be able to make up the cost of the swap with the difference in fuel economy savings, but it would be cool to have a 6sp tranny for towing purposes, as well as improved fuel economy. Again, refer to the first paragraph...sometimes a "long way around a short problem" kind of guy.

o Has anyone ever done this successfully? What about in a 2wd Excursion? Any differences versus the pickup that I should be aware of? Feedback?

o What would a swap cost me? I figure a net of around $3-4k after selling off the auto tranny, which is still in good shape. I have a shop, and a hoist, so labor is not a concern.

I am a fan of 6-spd, and I think it would be cool to see one in an X. As long as you're not doing it to save money, go for it. 3-4K is probably a good estimate. It will be 3 K for the tranny alone, but you can make some up selling your tranny.

So, those are my crazy ideas. What do you guys think? Feel free to berate me publicly, LOL, but bring facts, not just your feelings when you do. I'm here to learn.

Thanks,
Kevin

You have the wrong rig to try and make fuel economy, and some of your ideas are wrong, also. However, a little research and some effort, and you, too could have a 22 MPG X. I just don't think that even with CRAZY mods you'll get any better than 22. Also, the best way, hands down, to save fuel is not to mod the truck, but yourself. Drive for fuel economy, and you'll get better FE. Bottom line. Here is what you have going against you:

Ex (Terrible aerodynamics)
4x4 -2MPG
Bigger tires -2 MPG
Auto Tranny -3 MPG

The best mod I've heard is putting a manual in it and then drive it like a granny. However, if you are doing it to save money you are headed down the wrong path, as stated before...

 

[CHPMustang]

Howdy Kevin I don't recall which mods you've done to your Excursion but know from experience the AIH delete,CCV re-route and cool air intake helps performance and mileage.

When programming the truck we've found the performance mode 80HP(SCMT 1700) to give the best mileage along with keeping the transmission shifts under 2,000 RPM's and highway speed at or under 65 MPH.

Tire wise we went to 285's for a better ride but quicly discovered the truck accelerates mucho better and the speedometer is way more accurate.

I didn't answer all your questions,just giving you my .02 on it

Bill

 

[whatabudro]

Hoss I gotta meet ya, you know how to shoot starit, and know what your talkin bout from what I see. Want some Brisket? Come on down to Texas, stay a while.

 

[KevinsOffroad]

Thanks for the feedback, guys. Bill, currently I have the desert-storm air intake. Can't recall the name of it right now, but it does bring in cool air. I also ordered up the fender-vent foam dealie, but haven't installed it yet. The only other mod is the Juice w/A.

Hoss, just so that you don't understand my intent, I'm not looking to build a a 30mpg Super Duty. I apologize that I didn't make a more clear post...everyone probably misunderstood, as I'm re-reading. I simply want to improve the fuel economy to the best number that "we" (collective) can achieve in "normal" driving circumstances with this 4 Ton beast. Oh, and mine IS a 2wd, actually. I agree about the aerodynamics...not much I can do about that other than keep the speed down. I think that I read somewhere that wind resistance increases...I dunno...double for every 5mph or whatever it was. Point being, speed kills economy. I run it to work and back at 55mph, which IS the speed limit, but everyone goes 70mph, so I'm in the slow lane. I drive with an egg under my foot, and baby it each and every time I can. I never let it rev above 2k when shifting. My thought about the taller tires was NOT to increase the height...which I was trying to stay away from...it was to give a longer rolling circumference to slow the RPMs down slightly at the SAME speed, corrected for odo inaccuracy, obviously. I fig'r that there has to be an IDEAL RPM for my type of driving. I am guessing that it's a higher ratio than I currently have, since I have a 3.73:1 from the factory (like everyone else) which is a "multi-purpose towing and cruising" ratio. I was thinking that swaping gears out to a 3.23:1 might be an improvement, but I haven't found anyone selling anything taller than 3.54. Seems like a waste of time/effort/money to swap to only one ratio lower, so I was thinking that I could put taller tires on first, see if the economy went up, then swap the gear set to 3.54 with the stock tire size, get a baseline number, then swap back to the taller tires again to see if there was any realized gains in MPG. The tire swap would cost me around $100 for a pair of used ones (for experimentation sake only) and would tell me what increases in MPG I would see if I were to drop a ratio and put the stock tires back on. I have the stock wheels laying around, so putting them on and off again is not a bad deal. At least I don't have to mount/dismount them. A gear swap is going to cost me around $350-$400. The tires are less permanent, and less expensive. I know you said that the taller tires would DECREASE mileage, but were you talking about the ratio changing, or just because the rig was now going to be taller in the rear (temporarily). If putting smaller tires on it will help me (and after I try the taller ones, I may find that smaller is the way to go), then I'm totally and completely all for that. The lighter the tire, the less rolling mass I have to speed up (and slow down). I have a couple of Jeeps, so having 4wd on the Ex would have been silly in my instance...so I specifically looked for a 2wd, simply for fuel economy gains.

Anyway, hopefully that clarifies my position. So far, I've learned from you guys that there WOULD be some MPG gain to putting a 6sp in, and that I need to turn up my E J/A up a notch or two and experiment with that. Oh, and I drive around 12-15k miles/yr. If I got a 4mpg improvement in fuel economy (17=>21), it would take me 104k miles to pay off the tranny swap based on $3/gal. More if fuel prices are lower than $3/gal.

As you said, threejacks, $3k~$4k buys a hell of a lot of fuel.

Any more input/experience with going to a taller ratio??

Thanks,
Kevin

 

[Hoss 350]

Thanks for the feedback, guys. Bill, currently I have the desert-storm air intake. Can't recall the name of it right now, but it does bring in cool air. I also ordered up the fender-vent foam dealie, but haven't installed it yet. The only other mod is the Juice w/A.

Hoss, just so that you don't understand my intent, I'm not looking to build a a 30mpg Super Duty.

Thanks,
Kevin

I understood perfectly. I think it is cool whenever a guy decides to try something new and blaze new trails. My post was simply to help you realize (in case you did not) that your Ex was the wrong rig to try to make an econo-box. It appears, as I thought, that your intent was to just tinker with the Ex to try to get better performance out of it, which I think EVERYBODY on this forum understands. Your performance comes in the form of fuel economy, others in the form of big HP. I can think of no "aftermarket performance" application that we use these rigs in that they are really great at. An 8,000 lb truck is not good at drag-racing, but we use them for that anyway, not to go fastest, but to go fastest IN AN 8000 LB TRUCK . A SD is not a particularly fantastic sled-pulling rig (wanna pull a sled? a factory John Deere tractor will outpull even the craziest modded PSD on any day of the week) but we take them to the pulls anyway to be the best puller in a SD. A SD is not the best off-road, even a slightly modded Jeep will beat a SD in almost anything off-road, but we still take them out to be the best off-road SD out there.

In your case, a SD is not the best fuel economy getter, but you are going to try to make it the highest FE SD it can be. I don't think there is anybody on here that can't understand that at least on some level!

Let us know what you find out. Oh, and if you put big tires on the rear only, you may very well see at least some of the benefit of a higher ratio, because it would not increase the leading edge much.

 

[Hoss 350]

Hoss I gotta meet ya, you know how to shoot starit, and know what your talkin bout from what I see. Want some Brisket? Come on down to Texas, stay a while.

My in-laws live in Arlington, so I get down there once or twice a year. Her Grandparents have a ranch down in Dublin, we go down there to cook up brisket whenever i come down. Brisket is lost on most folks up here, but i can't get enough of it. Makes a great sandwich

As far as shooting straight, I got 7 pheasants this last weekend with my year-old German Shorthaired Pointer, and I only shot 9 rounds. Not bad by anybody's standards

BTW, not to hijack, but anybody that has ever put the hours into training up a bird dog, to take her out on her first hunt and have her perform FLAWLESSLY knows why I mentioned that. I've been on cloud 9 all week!!!

 

[KevinsOffroad]

I understood perfectly.<snip> It appears, as I thought, that your intent was to just tinker with the Ex to try to get better performance out of it...

Let us know what you find out. Oh, and if you put big tires on the rear only, you may very well see at least some of the benefit of a higher ratio, because it would not increase the leading edge much.

Yep, 'ya got me perfectly!! That's exactly what it's about. I like tinkering, as I think we all do. My business (KevinsOffroad.com) began by tinkering. Turns out, other Jeep owners wanted to pay me to tinker on their Jeeps. Anyway, the cool factor of having a 6sp in an Excursion is probably the #1 reason for doing it...just to be able to stand back and admire my efforts later (assuming I don't screw anything up that I can't fix, lol). A close #2 would be for the fuel economy savings. #3 would be for the uphill towing ability of a close-ratio standard tranny.

Anyway, thanks for the input. I'll definately let ya'll know what I find out with the taller tires in the rear.

Thanks again for the input. If anyone has any links or info on a manual swap from an auto and all of the intricacies that be, please post 'em up. I'll start my research and see what's involved ASAP.

Thanks,
Kevin