2005 Ford Explorer, 4.0 SOHC + 4WD. Stock EPA Figure: 15 Combined.
 

I got this car at 153k miles, and I was getting about 14 MPG. I raised the Tire PSI from about 30 to 40 & used Amsoil Performance Improver. That made a good improvement, I think the injectors and valves were dirty. That's just basic stuff, though.

In Mid June 2021, I replaced oversized tires with the right sized tires. For a while, that made a 1 MPG increase over the old ones.

As of September 2021, I was getting about 20 - 21 MPG with minimal mods, but EOCing wasn't the best idea.

In October 2022, I added a 600w block heater. I also re-added the WAI tubing, and the grill block. The car has been getting 18.1 - 19.1 MPG, according to the on-board meter (which is accurate.)

Specs:

Auto Trans
Ford 4.0 Engine
Stock Mechanical Belt-Driven Engine Fan (ouch.)

Fluids:

Amsoil 10w30 Oil
Amsoil P.I. (Performance Improver [Injector and Valve Cleaner]) once a year, minimum.
Amsoil DOT 3 Brake Fluid
Unknown ATF (I'm not changing it, for concern of trans failure.)

Differential (Gear) Oil:
??? 75w90 Front,
Mobil 1 75w140 Rear.

Mobil 1 is the thinnest Gear oil (in those viscosity ranges) that I know of, and I expect it to slightly push fuel efficiency in my favor.

Gasoline Mostly Used: Top Tier Gasoline, E10, 87. Usually bought at a Citgo station.

~~~~
Mods:
~~~~

(Mods last updated 2022 - November - 9.)

Aero:

Air Dam (Floor Mat attached to the existing Air Dam. Goes down to 5 inches above road surface.)
Roof Rack Delete

Engine:

600w Block Heater
Grille Block (3/4)
Warm Air Intake (Cold Air blocked, hole in air box added, clothes dryer ducting added that goes to exhaust manifold near oil filter.)

Driving Behavior Mods:

Alternate routes in town (traffic permitting,)
Driving a bit slower,
Engine off at lights,
Timing lights.

Tires:

Cheap, Stock-Sized Tires: 235/70/R16,
Tire PSI (Read while Hot) is: 45 Front, 49 Rear.

Other Mods:

3rd Row Seat Removal.

~~~~~~~~~~

Planned Mods:

Heat Retention
Wheel Skirting, Partial Front Wheel Skirting & Partial or Full Rear Wheel Skirting

Considered Mods:

Electric Fan - Not sure what to do here. Maybe use a fan off a Taurus or 95 Mercury Cougar. I expect this would be a 2 MPG Increase.
Indexed Spark Plugs - Just a little detail in the big picture. Probably good for 0.1 - 0.3 MPG.
Partial Kammback

Less Considered Mods:

Power Steering Delete - 1 MPG, maybe?
Manual Transmission Swap - Some 2002 - 2003 Models came with a Manual Transmission, and there are guides to this. It might help by 2 MPG or more.
Re-Tuning - Not sure how much this would help.
Water-Methanol Injection - Requires re-tuning the engine to make use of this. This might be a 3 or 4 MPG Increase, but it also includes extra parts, and extra fluids to use.

Mods I'm Against Doing:

Side Mirror Deletes - I once had a far too close encounter with someone who nearly side-swiped (more like rammed) me from a highway on-ramp to consider this. If I didn't look in my side mirror the very second I did just as a habit, I wouldn't have slammed the brakes, and they'd have barreled into me at about 75 - 80 MPH when I was going 50 in a 55 zone, with no-one else on the road.

- Austin

Take a look at this:
https://www.explorerforum.com/forums...ge-tips.44372/

Thanks for that, and I did learn about Indexing Spark Plugs there, but Al Franklin seemed to be more about throwing money at his vehicle than using low fruit mods. It's good to know, and there are some interesting mods there. I think I'll pay attention to Funkhoss' 94 Caprice Wagon, and Diesel_Dave's efforts, though

I'll just start with low hanging fruit mods, first. I plan to mod it to get at least 25 MPG tank to tank, and I've gotten to 20 recently (a 2.5 to 3 MPG improvement,) mostly thanks to EOCing. I only recently found that I had to set my SG2 engine setting to "Hybrid" to keep it on during EOCs.

I have yet to take the Roof Rack off, and I won't be doing it until the end of this current tank, which I'm somewhere in the middle of.

I had a baseline for this vehicle: about 17 to 17.5 MPG in Summer months, without Hypermiling, in Rural Pennsylvania. Not the best figure, though it did beat stock by a bit due to the tires being set at 45 PSI (Hot.)

Having tried that, I experimented with adding Amsoil Upper Cylinder Lubricant to the Gas at fill-up. On a trip, it did improve the mileage, but not enough to pay for itself; it only raised it by maybe 3/4 of one MPG. I compared the SG2 figure (which was calibrated) to the On-Board figure (which is aaccurate.) That bottle of Amsoil UCL cost me $5. Even if I bought it with the Amsoil discount, it would come out to $3.65. Unless Gas goes up to $5 per gallon here, it's not worth it.

Having considered that, I started putting Opti-Lube XL ("Xtreme Lubricant" Diesel Additive) in the tank, since 1: I had it, 2: it's much cheaper by the ounce, if you buy it by the gallon, and 3: It seems to beat Amsoil in Lubricity, too (if I'm reading the data sheets right.)

Amsoil UCL:

Pump Gas - 807 µm Wear Scar.
With Amsoil UCL - 640 Wear Scar, a 167 µm Improvement.
Cost: $3.65 or $5.xx for a 6 Ounce Bottle (1 Treatment)
https://amsoilcontent.com/ams/lit/da...tins/g3657.pdf

Opti-Lube XL:
Pump Diesel - 440 µm Wear Scar.
With XL at High Treat Rate (Edit: that's 2.5 oz / 10 gallons,) 220 Wear Scar, a 220 µm Improvement.
Cost: $40.16 per Gallon (not counting shipping,) or $1.8825 per Treatment of 6 Oz per Tank (slightly higher than the 2.5 / 10 gal treat rate.) $1.568 per tank at 5 oz / tank (slightly under the treat rate.)
https://opti-lube.com/downloads/intertektesting.pdf

Based on these two data sheets, Opti-Lube XL should give me a wear scar equivalent of 587 µm, and it should cost much less. EDIT: I was using 4 Oz, not 5.625 oz per gallon. The wear scar would be higher, but

"XL" is Opti-Lube's best additive for increasing Diesel's Lubricity. I started at 2 oz in a tank, then I raised it to 4. I know that this works to raise lubricity in Diesel, and it may work better in Gasoline than Amsoil UCL. My concern is, it isn't designed specifically for Gasoline, so I'm concerned for the long term effects on the car. I'm not sure if it's working to raise mileage, but I'm going to put another 4 Oz in at the next fill up. My mileage has improved recently, but I'm not 100% sure why; I've also been improving with my EOCs.

The current tank is looking like it's shaping up to be somewhere around 21.5 MPG, although I'm not done with the tank yet. I didn't start the tank out with the SG2 set to "Hybrid," so I don't have the most accurate figure.

EDIT: That tank ended up being 20.21 MPG.

Wow. I just got 25.8 (or a bit higher?) on a return trip of 32 or 33.8 miles (google maps tells a higher story than the computer.) Most of it was just because I was driving slow on a highway, and EOCing. That's not even with any big mods done to the car, and it still has the roof rack on. The EPA HWY figure is 18 MPG.

Since I learned that I could set my ScanGauge II to "Hybrid" to keep the meter on during engine-off coasts, I'm sure that helped my mileage; I think I'm getting better at EOCing. It also allows me to have two average gauges. 1: The On-Board computer, which I use for the overall average; 2: the SG2, which I'm using for the trip average. I haven't re-calibrated the SG2, but it's close. I've been making logs of trips for the last few tanks.

I re-filled yesterday, and netted 20.2 MPG. These last 3 tanks (all with Opti-Lube XL) were 20.3, 20.07, and 20.2 MPG. I'm still not sure if the Opti-Lube additive is helping much. Because I've been getting better at EOCing, that may account for the mileage being just over 20 MPG now.

When I filled up the tank yesterday, I also added 24 Oz (3/4 of a bottle) of Marvel Mystery Oil to the crankcase; the oil was a bit low, and I'm near oil change time. My overall average has increased over the last 83 miles to 21.5, but that's just over one day, and the engine had already been at 195 F when I filled the tank. I'm not surprised about a mileage increase, since the oil's thinner now; I also saw oil viscosity-dependent mileage differences when I was trying different oils in the Suburban.

Yesterday, I picked up a cheap tarp, to use as a grill block. It's not attached yet. I also picked up some silicone, for the roof rack delete. I'll probably make these changes before this tank's over, and then I'll change the oil maybe mid-tank or at the end of the tank.

EDIT: I removed the Roof Rack today. The bolts are still in the roof. After I sanded the rust off the bolt inserts and cleaned the roof, I put Silicone on the bolts to keep water out. I haven't driven the car yet.

EDIT 2: That tank, with the MMO in the crankcase for the whole tank and with the roof rack off for 353.2 of 437.1 miles, turned out to be a 20.62 MPG Tank.

If you pump your tires up to 55F/52R you should get about a 3-4% bump in FE and it will handle better. Just did this on my ranger. Now I don't bounce off potholes and can turn sharper.

Is your Explorer a manual? EOCing in an automatic could damage the transmission.

^ No, it's automatic. I've mostly stopped EOCing, and I found another way to shut the fuel injectors off. Besides going into 3rd gear above 35 MPH and down a hill to turn on open loop mode, there's also this method:

Above 40 MPH, turn Cruise Control on. Hold the Coast button, and the engine should shut off the injectors in a few seconds. It doesn't always do this, though. This doesn't slow the car down as much as going into 3rd gear, so I have more opportunities to go into open loop mode.

However, the computer sometimes gets the button inputs confused, causing the car to accelerate when I hold "Coast." In this case, I go into Neutral and then I EOC just long enough to restart the engine. That usually fixes the problem.

Oh, and I added a 600w Block Heater about 10 days ago. It helps pretty well when I first start up if I've had it plugged in for 4 - 6 hours, but I'd like to add a second coolant heater somewhere.

How well does the block heater help? After 6 hours of heating and on a 71 degree day, and going by a landmark that's within 2 miles, my ScanGauge read 18 MPG AVG at the landmark vs. the 15 MPG that I'd normally get on a "good" run. Then again, that's also with some slightly better traffic than I would usually get. Maybe I should count this as more of a 2.5 MPG increase in short distance, on "good" (warm) days.

EDIT:

The cruise control open loop method doesn't seem to be working as effectively lately. Sometimes I can start at 45 or so MPH and stop above 40, but other times I have to go upwards of 47 - 50 MPH. I'm not sure why?

Also, I haven't yet added an Air Dam. I need to re-add my hot air intake for these colder days, too. I've just had the side of the air box cut open to the engine compartment, which doesn't seem to help much if at all.

Today I made a few modifications:

I had 1/4 of the Grill Block on already, and I added the majority of it back. I only used Duct Tape, which gets pushed in by the wind. I should probably add some harder plastic behind the tape.

I also re-added my Warm Air Intake. I briefly had it on in May or so, but removed shortly after because I had damaged where the cable attaches to the sensor. My W.A.I. uses Clothes Dryer Ductwork from Home Depot to draw air from the Exhaust Manifold near the Oil Filter. It's a bit simple and rough.

I didn't make any A-B-A-B tests of these yet. The car seems to require slightly less throttle while driving, but that's hardly a test comparison.

I had the block heater on for some hours today, and I had the meter up to 110 F before starting the engine, when the temperature bottomed out at 100 F.

This tank is only about 40 miles in now, and the mileage is now 17.6 according to the on-board meter. I managed to get the meter up to about 22 on a short Highway trip today. The 17.6 MPG part is about the same as summer mileage which only had 1/4 of the grill block, the roof rack removed, and the tires up to 44 front / 48 rear. However, I did do upwards of 18.1 - 18.3 from June to July, with fewer mods than I now have.

============
Next Planned Mod:
============

A Bigger Air Dam. This ought to help by at least 0.5 MPG, maybe up to 0.7 MPG (as I've read here at Ecomodder.)

I already have the Zerostart 3100039 600w Block Heater. I had considered adding another heater, and according to the site below, the Zerostart 3100040 600w Block Heater will also work; it's just for a different location, and it's aimed at 7 o clock instead of 6. How fortunate?

http://www.showmetheparts.com/philli...oapplications/

Why would I want that? Well, I want more heat at launch in the dead of winter. Only one 600w heater isn't a whole lot, that'll just take some of the edge off. It'll likely get me above the freezing point, but it's just better to have two in Pennsylvania Winters. EDIT & UPDATE: I looked at photos of the Ford 4.0 Engine, and it seems as though this won't work. There doesn't seem to be another freeze plug on the engine. If I find another one on just this car, then I'd like to get another heater. Otherwise, no.

Also, "Oil Pan 4" has posted this experience about using two 600w heaters:

"This one is easy.
Install a second stock engine block heater or find your vehicles stock heater, get 2 of them and install.

What does that do?
You might think it wastes double the power.
It actually saves power. Instead of leaving the standard single 600 watt heater plugged in all night I have found that you really only need about two hours with double block heaters to reach close to the same level of heat you get running a single block heater all night."

(Source: )
https://ecomodder.com/forum/showthre...ers-34712.html

Also according to the ShowMeTheParts site, I can apparently buy an Oil Pan / Transmission Heater (Zerostart part 3500047,) but that seems a bit much; it's $115 on eBay, for one. Besides, Oil Pan 4 provided a guide for how to do that as well (linked below.)

https://ecomodder.com/forum/showthre...ter-33500.html

Good luck with your endevours

Thanks.

There's not much to report now, except that I've been getting 18.6 - 18.8 MPG lately, with the few mods I have. I'm somewhere over 200 miles into the tank now, maybe around 225.

I'm close to putting some Fiberglass in the engine bay. I can't put it everywhere, but where I can keep heat in, I expect that to help. EDIT, Nov. 9: Maybe I should use a different method.

I've found myself enthused about the idea of putting the air dam on. The car's on stands now, for the next day.

Current Mods:

600w Block Heater;
Driving Behavior (Engine Off at Red Lights, Fuel Injectors Off where possible; )
Grill Block, Roughly 90% Blocked;
Roof Rack Delete / Roof Rack Removal;
Tire Pressure: 45 Front, 49 Rear (give or take, depending on changing temperatures; )
WAI (Warm Air Intake.)

The next day, and the air dam's installed. It doesn't cover everything, there are 5 inches from the road that are not covered.

I wouldn't worry. To cover everything would add frontal area. For instance, my Superbeetle has a tow hook that hangs down another 1-1 1/2".

Does it have a notch in the center to make a central jet?

Most Recent Tank:

2022 - 11 - 08:

That tank went better than expected, if the final readout's right (I went to my usual Citgo station, instead of the B.P. station I went to the previous time to save $1.48.) The on-board meter (which was very accurate before mods) said 18.5 for this tank, but my current tank calculations say this:

18.71 MPG
290.1 Miles
15.506 Gallons

Only about the last 25 miles have the Air Dam on, so its effects aren't evident.

I admit, I did some EOCing this tank. I normally don't (and I don't want to,) but some road construction sapped my F.E., so I did on a few occasions.

Again, I have to stress the fact that using both 3rd Gear and also Cruise Control to shut off the injectors in certain speed ranges (and usually downhill) is helping my FE.

EDIT, 7 June 2023: This tank was not right, because I switched gas stations. The next tank was lower.

About Engine Heaters:

I'll keep up with using the block heater. It doesn't raise the temperature clear to operating, though; the most I saw was 136 F, before starting. I'll need to add another heater or two if I want it to be at or near operating temp right at the start.

I don't think this 4.0 has room for another block heater. Earlier, I said it looked like it did, but now that site seems wrong. I've looked at photos of the Ford 4.0 Engine Block, and as far as I can tell, there isn't another freeze plug. I think I need another immersion heater, but I have qualms against just using Kat's Heaters; they don't have the best reputation.

I have an early 1960s Heater with an element that sits in the coolant system. I don't know its wattage, or if it works and won't leak, and it needs a new electrical cord. Maybe I'll use that, but it's too early to say much about it.

I bought a 1500w water tank element from Home Depot some months ago, after seeing a thread from Oil Pan 4. I remember he said that he had heaters that were only screwed together, so I'm thinking of going that way.

Next Up:

Rear Wheel Skirting. It doesn't have to be super fancy, just some plastic that's well attached, maybe with an easily bent strip of aluminum to screw into.

Also, I need to change the oil pan gasket, along with the oil and filter. I've been using Amsoil Signature Series 10w30 + a FRAM Titanium or FRAM Ultra Synthetic filter (some of the best filters available, short of adding a "bypass" kit,) so I should still be good for a bit.

At the same time of the oil change, I plan to fill up the tank and add a bottle of Amsoil Performance Improver (for cleaning the injectors.) I don't use it every 4,000 miles (according to the bottle,) but once a year seems OK.

Frankly, I'm not sure what you mean by "a central jet," though I might guess it.

Oh, and the car has an Anti-Deer Bar on it. I've never hit a deer with it, but it's there.

An extreme example
https://ecomodder.com/forum/attachme...p;d=1565844879
ecomodder.com/forum/showthread.php/front-splitters-do-they-work-37762.html#post604784

On a Toyota Supra
https://i.pinimg.com/originals/6c/1c...47c0141cb9.jpg
i.pinimg.com/originals/6c/1c/dc/6c1cdc8b320487a11334ff47c0141cb9.jpg

A splitter, same deal
http://trackdogracing.com/images/pro...splitter_d.jpg
http://trackdogracing.com/images/pro...splitter_d.jpg

I think the idea is a faster moving, unimpeded central jet draws air from around and between the tires. Just something I've seen. The other extreme is a small tab [or spat] in front of the tire.

Thanks for the idea, but I don't think I'll be doing that - at least not right now.

============
Recent Changes:
============

Around 200,500, I changed the oil for the first time in nearly 2 years, and about 15,000 miles. Don't worry, though: I was using Amsoil Signature Series 10w30 and a Fram Ultra Filter, which is as good as an Amsoil Filter, only cheaper. At the same time, I took the oil pan off and made a new gasket for it, since I wanted to keep oil from leaking. I still have to re-gasket the Valve Covers, though.

I also changed the Air Filter with a FRAM Ultra (I was at least 25,000 overdue,) then shortly after that, I plugged the Warm Air Intake with the rag plug from the Cold Air Intake; I was getting tired of the low power up hills.

Lastly (after the most recent fill-up,) I need to get new tires soon anyway. Because of that, I've aired up the Front to 48, and the Rear to 53. That's working for maybe 1 MPG compared to 44 / 48, according to my gauges so far (though I'm not even 50 miles in.)

==========
Recent Tanks:
==========

The last 3 are averaging to 17.8. Two of the tanks were dragged down by me going to yard sales for 2 weeks in a row, and I expect this tank also will turn out lower than it could have been, because it's yard sale season.

I really need to get on the ball with that rear wheel skirting. I don't expect a giant difference, but it should help.

The Block Heater, in this 60 - 85 F degree weather, can usually get the engine to around 125 - 144 F before I start it. That's not accounting for after the antifreeze circulates through the engine, which lowers the temperature.

==========
Idea for Mod:
==========

Maybe one can call it goofy, but I've had the idea of making a Transmission Pan Heater with an old Waffle Iron that's kept at a low temperature,depending on the weather. If I can attach it well, and prevent water from getting in, I don't see how this couldn't be a very cheap and efficient way of slightly warming up my transmission before starting the car. I do have a dented 1960s Waffle Iron that I paid $1 for in a yard sale, and it's not doing much good with waffles anymore - the top and bottom don't line up quite right.

OIL Viscosity
 

The engine from the factory was made to run on 5W30 from the factory, but I do understand the thinking of running higher weight due to mileage but this engine has very tight bearing clearances, unlike the old pushrod engines of the 60s-80s, just my two cents, keep up the good work!

Being an old timer: you ran thicker oil to prevent oil bypassing places where it should stay. Usually you found external evidence that it was leaking like a trail of smoke when accelerating, trail of smoke decelerating , smoke cloud idling. Oil fouling the plugs. Note the trend. With 50 weight you primed the crankcase with fuel to thin the oil enough to start an aircraft engine any time it was colder than 45f otherwise it wasn't going to crank.

Todays stuff has tighter clearances used than olden days had as new

The truth is, I haven't gone up in range much at all, as far as precise viscosity's concerned. I've even gone lower in viscosity range (when hot) compared to the 5w30 that I could have used.

The numbers on the bottles just refer to viscosity ranges, they're not entirely accurate numbers. I haven't even gone outside the 5w30 range (read on for that.)

Data Sheet Viscosity Specs for Amsoil Signature Series 5w30 and 10w30:

5w30:

Kinematic Viscosity @ 40ºC (104ºF,) cSt (ASTM D445) --- 59.7
Kinematic Viscosity @ 100ºC (212ºF,) cSt (ASTM D445) --- 10.3

10w30:

Kinematic Viscosity @ 40ºC (104ºF,) cSt (ASTM D445) --- 62.3
Kinematic Viscosity @ 100ºC (212ºF,) cSt (ASTM D445) --- 10.0

Compare them to Pennzoil Synthetic Blend 5w30:

Viscosity
@ 40°C (104ºF,) cSt ASTM D-445 --- 60.4
@ 100°C (212ºF,) cSt ASTM D-445 --- 10.5

Also, compare to Pennzoil Gold Synthetic Blend 5w30 (the thickest I've compared to, thicker than my 10w30, yet it's still a 5w30: )

Kinematic Viscosity @ 40C (104ºF,) cSt ASTM D445 --- 63.2
Kinematic Viscosity @ 100C (212ºF,) cSt ASTM D445 --- 11.0

(Links to these Data Sheets are at the bottom.)

So, my 10w30 is thinner than one (and probably more) 5w30s in the given temperature ranges. Yes, it's thicker when colder than the Ams. Sig. Series 5w30, but I'm using a block heater anyway.

Yeah, once you get to the 50ºF range and below, the viscosity could be a good bit higher than it may otherwise be with an Amsoil Sig. Series 5w30 or 0w30. I'm not worried, between my block heater and the idea of attaching an oil pan heater.

Also, on a non-fuel economy subject, the engine does run a tiny bit quieter than if I was using Pennzoil Platinum 5w30. I used that for a while, and comparatively, this Amsoil Oil makes the lifters quieter downhill in 3rd gear than I ever heard them before. Before using Amsoil Sig. Series oil, they weren't worryingly loud, but I did notice a bit of lifter tick. Now, I don't hear it near as much.

...

Data Sheet Sources:

Both Amsoil Oils:
https://amsoilcontent.com/ams/lit/da...tins/g2880.pdf

Pennzoil Oils, respectively:
https://s7d9.scene7.com/is/content/G...24561pdf?$PDF$

https://s04.static-shell.com/content...-Motor-Oil.pdf