Fuel Economy Improvement

[Ralph E]

I did a quick search and couldn't find anything on this. I was curious if anyone had any suggestions for products they've used to increase their fuel economy? I have a cold air intake and high flow filter, but nothing else really. I'm thinking about doing maybe performance wires and plugs, but I've heard the explorer is "sensitive" to the plugs you use.



I've been doing a ton of road trips and my vehicle always gets used because it's really convinient, except in the wallet...

 

[Tommy Moore]

I have been told the SCT X3 Tuner is great along with a cold air intake and a Zabteck throttle body. It also increases your throttle response and horsepower. I will know Saturday when I pick up my "new" 08 Adrenalin with all the modifications I just mentioned plus alot more!

 

[Robert Caffyn]

+1 on A22 comments. I have all of that and get about 18 to 18.5 mpg with some spirited driving. I've seen 20mpg long haul highway driving, the V8 is just plain old thirsty and it has to be driven lightly to see those numbers on a regular basis. BC

 

[David Ponder]

Keeping the engine tuned correctly and tires inflated correctly, (Perhaps even a # or two over) is the best thing you can do for fuel economy. While the SCT X3 will give you better performance and fuel economy, but IMO it would be a long time before it paid for itself if you are just getting it for the fuel savings.



For me, my 2001 is bone stock except for upgraded shocks, and sway bars. (Added handling) The best increase I had in fuel economy was replacing worn plugs at 99,000 miles, Replacing a leaking vaccuum hose (the famous cracked elbow), and running the tires slightly higher than what the door states. (I run 37PSI rear, and 35PSI front) I get 20-22 mpg on the highway pretty consistently now. (I have 139,000 on my ST now.)

 

[Todd Z]

A true COLD air intake will NOT increase MPG........ The colder air is more dense..... thus more fuel is needed to make the mixture work.....



Todd Z

 

[Jim parnell]

find a light/easy foot on the gas pedal, keep the rpms as low as possible at all times, don't carry any more weight (stuff in the bed/cab) than necessary, don't use the AC, can overinflate the tires by 3-5 psi with no issues.

 

[Richard L]

I suggest that it is debateble as to whether any device can improve gas mileage enough to offset the purchase price...



An economy tuner like the SCT can help but cost of the tune, the cost of gas, and the miles you drive would need to be compared to see how long the payback would be.



Obviously the way you drive has the biggest impact on gas mileage. Many people don't really drive for maximum MPG but think they do. Many people think that the speed you drive is a major factor when it really is the stop and go acceleration that eats most of the gas.



I alway recommend that you get some kind of trip computer or scan guage that will give you an instantanious readout of the MPG you are getting at that moment in time. This will show you exactly what kind of mileage you are getting during all kinds of driving conditions. It will become obvious very quickly that anytime you increase the rate of acceleration, you will increase your MPG. Rapid acceleration will take a really big bite out of your gas mileage.



Traffic that requires you to slow down then speed up is terrible on MPG's. If you learn the patiences to drive in the slow lane and just go slightly slower than the traffic ahead of you, you will get great mileage because you will rarely ever need to change the speed of your vehicle. Of course all of this depends upon the traffic, which you have no control over.



...Rich

 

[OLE442]

Todd Z modded throttle body. Well worth the $$

 

[Johnny O]

The best bang for the buck is a cat-back exhaust. Second would be a tuner and throttle body.

"Performance" plugs and wires will get you nothing over what replacing old plugs and wires with stock parts would do.

On a level road with the cruise set on 65, I will get 22 mpg according to the dashboard thingy. It is rated at 19. Cat-back exhaust, K&N replacement filter in the stock airbox, otherwise it's all original.

City mpg is no different because it's a heavy SOB.

 

[Richard L]

JohnnyO,

I used to get 22 MPG doing 70-75 MPH on my trips to Louisville, KY in my 2001 and my 2003 STs. The only mod I had was a K&N drop in filter that I moved from my 2001 to my 2003. Of course, with your Cat-back exhaust system you would have more HP, but it really did nothing to improve your gas mileage, and it did not seem to hurt it either



That just proves my point, that speed equipment will increase HP, but does little or nothing to imprive gas mileage. Especially when just changing your driving habits will often get you the biggest mileage improvement, and it does not cost you anything.



...Rich

 

[Bill Koonce]

It's been said many times in many places: a gas engine is a large air pump. Anything that makes it easier to pump air through it will help power and fuel economy. Sorry Todd, but opening up restrictions will help. Yes, colder air is denser air. But we're not talking about WOT driving now. With a less restrictive intake and a colder intake charge, the engine will use less throttle opening to generate the same amount of power. If anything, the increased turbulence caused by a more closed throttle blade will lead to a more complete mixing of air and fuel in the combustion chamber. That leads to more efficiency, and better fuel economy.



The hissing sound of the stock exhaust when I get on the throttle is a classic sign of a very restrictive exhaust system. I agree with JohnnyO that opening up the exhaust is probably the best single thing to do, although prices vary widely; an expensive custom exhaust will not give a great "bang for the buck" although it will increase performance and economy.



A flash tune that's specifically made to take advantage of better flow, and to give maximum economy at the expense of top power numbers is the glue that ties other fuel saving measures together. Even without a custom tune, your driving habits are learned by the PCM, which will adapt the system somewhat. In any case, being light on the throttle, and coasting to stops instead of hard braking will give better fuel economy.



Don't forget other things like vehicle weight. Do you have a 500# box of tools and other stuff in the back? Leaving all but a bare-essentials emergency kit will save weight, which saves gas. Keeping the tonneau cover at home will also save weight. It might also lower drag as well by providing a zone for a cushion of air to form over the open bed with the tailgate up. This was tested in a real wind tunnel for a "Mythbusters" episode.



Maintaining proper tire pressure is important for safety reasons first, but is also good for fuel economy.



Don't expect miracles, though. The S/T has the aerodynamics of a brick. And since drag increases as the cube of velocity (v^3), the surest way to save gas is to drive very slowly.

 

[Richard L]

Mustang Guiy,

With a less restrictive intake and a colder intake charge, the engine will use less throttle opening to generate the same amount of power. If anything, the increased turbulence caused by a more closed throttle blade will lead to a more complete mixing of air and fuel in the combustion chamber. That leads to more efficiency, and better fuel economy.

None of the above will significantly improve fuel economy. Manufacturers are trying to make their engines as fuel efficient as possible while still providing as much performance as they can and still meet all governmental regulations. All performance modifications are based on WOT and improvements in the engines breathing only provide more air for high RPM operation. Adding equipment to increase HP will not do much if anything to improve fuel mileage, and will often hurt mileage because you are shifting the design parameters to favor more HP.



You can add some equipment like intake and exhaust systems to improve HP without hurting gas mileage, but they do little to improve gas mileage. Equipment like SCT tuners can improve mileage to some degree but their slight improvement in mileage is often offset by their higher cost and results can very depending upont the skill of the tuners program.



The simple fact is that it takes a predetermined amount of HP to move a specific amount of weight a specific destance. I think the simple formula for one HP is lifting 750 lbs one foot. If it takes 50 HP to move a 4300 lbs vehicle down the road at 50 MPH, then that same engine creating 50 HP will require the same amount of air and fuel to do that task regardless of the total HP capability of the engine at maximum power. If you attempt to accelerate to 50 MPH at a much faster rate, you may be applying 150 HP or more, you get that 4300 lbs vehicle to 50 MPH much faster, but you will pay a stiff penalty in fuel mileage. It is the slowing down and speeding up that eats gas mileage. Of course that varies with traffic, but in general that is mostly avoidable with good driving habits.



...Rich

 

[David Roll]

This is a great (and interesting) discussion. I appreciate you all posting such detailed explanations of your logic.



I just guess my driving habits suck! :driving: But I am having fun! :cheeky:



Dave

 

[Jimmy Lavoie]

I just guess my driving habits suck!

I drive like an old lady and I get 17-18mpg in town and 22-24mpg on the highway. Towing on the highway gets me around 14-15mpg.



It ALL depends on the highway speeds and quick starts in the city.



It's been pretty consistent but when I feel like playing, my in town driving can easily average 12mpg.

 

[Todd Z]

Racing world and things like that YES.....



Daily driving ST people expect a miracle..... NOPE....



to go from 272 RWHP to 210 RWHP on the gen 1 4.0 Minus a FI setup or NOS..... Probably close to $2,500 for a MPG gain ( IF you keep your foot out of it) of 5-8 mpg....



Most of the ST mods are for WOT HP only......



Todd Z

 

[Richard L]

justjimmy,

It ALL depends on the highway speeds and quick starts in the city

It is really not much difference in mileage driving at 60 and driving at 70, as long as you are not changing speeds. The higher speeds cost you mileage because you will be slowing down and speeding up. If you are driving 70 when most others are doing 65 you will constantly be coming up on slower moving cars and trucks. You come up on a slowere vehicle and slow down, when the guy gets out of your way you speed up to 70 or faster to get around him. If you do that in fairly heavy traffic you will eat up a lot more gas than just going at one speed slightly below the average speed of the traffic. That way, you will have far less incidents requiring you to slow down and speed up and you will definietely notice a MPG improvement and you did not have to buy some additional equipment.



I like to recommend that anyone who wants get better gas mileage, investin in something like a ScanGauge or other accurate fuel mileage computer that gives instantaneous MPG updates. The will show you what driving habits are killing your gas mileage, and can be used to train yourself to drive economically.



...

Rich

 

[David Ponder]

Richard, back in the day some cars came with a "fuel economy" gague.. (Basically a vaccuum gague) I had a 62 ford that had one under the dash.



Anyway, an analog vaccuum gague connected to manifold vaccuum would be a cheap way to do what you suggest.. Just try to drive keeping the gague as high as possible.

 

[Jimmy Lavoie]

It is really not much difference in mileage driving at 60 and driving at 70, as long as you are not changing speeds.

I don't entirely agree. When I drive at 60, I get better mpg then when I drive 65, 70, 80 and so on - You certainly can't disagree with that.



I most certainly agree with the speeding up and slowing down... that makes perfect sense.



When I say I drive at 70, that's with cruise on and no traffic to slow me down. There are stretches of highway all over the country that allow those conditions depending on the time of day.

 

[mookie]

It is really not much difference in mileage driving at 60 and driving at 70, as long as you are not changing speeds.

While driving at a constant speed will give the best mileage for that speed, driving at a slower constant speed will give better fuel economy than a faster speed. This, of course, relates to aerodynamics/drag.

 

[Johnny O]

I get much better mpg going slower, which admittedly I don't like to do. I'll hit 22 in Florida but where I live in PA you can't drive a half mile without going up a hill so the best I get here is 19. I picked up 3-4 mpg with the exhaust then lost about 2 when I put more aggressive tires on it due to more rolling resistance.

IMO replacing the stock exhaust will help mpg because it is more restrictive in order to be quiet. Replacing the intake helps little because a 4.0 simply doesn't flow enough air at normal speeds to run into much restriction.



Oldie thread but a goody. Aldive (R.I.P.) at Explorerforum.com was trying to get 30 mpg just for kicks. Payback was not really an issue in this case.