Air Intake/ Fuel Economy??

[Tyler Fields]

Hello everyone. Long time reader, first time poster here. I was wondering if a cool air intake would help fuel economy out any? These gas prices are killing me and 13 mpg is not good either also, if I add a cool air intake will I need to flash or tune the ST to adjust to the increased airflow?

 

[scott degroot]

In a nutshell I'm gonna say no, an intake will not increase your mpg. There are a lot of myths floating around out there about what the average bolt on air intake will and won't do but one thing that holds true is that they drain your wallet more than they do anything else.



I don't know what kind of driving you do or what modifications if any you have but 13 mpg sounds low to me on a stock ST.

 

[user 64972]

Todd Z (Zabteck) modded throttle body and drive like there's an egg under the gas pedal.

 

[swshawaii]

 

[Tyler Fields]

I keep it under 60 and use cruise control all the time to keep my rpm spikes low. the folks on the explorer forum said thats the best thing you can do to keep mpg's up. I was wondering about the air intake cuz an engine will run better with more air, better exhaust, and proper fuel:air ratios. Those are the big 3 at least... Every brand from K & N to the cheap eBay intakes all advertise gains. I know it wont be 7 mpg like they all say, but 2-3 would still make a difference...



And what did that link have to do with anything? The 4.0 doesnt run off of ethanol

 

[Jacob Dryer]

04-05 4.0's did run on ethanol.. but that doesn't help you.



I'm a little surprised by your 13 mpgs though, is all your maintenance done? Do you have huge tires? I never saw below 15 even with city driving..

 

[Tyler Fields]

All maintenance is done. Every 4k miles I change oil and clean out my air filter. Clean fuel injectors. Check and adjust tire pressure. I drove around a lil bit today to make sure my numbers were right... I got 15 today. Guess my little sister was playing with my trip meter again :banghead: anyway, what can I do to help my fuel economy out? So far I've heard throttle body spacer.

 

[scott degroot]

I would be amazed if you saw a solid 1 mpg increase with just an air intake, I'd be surprised if you saw that with an intake and exhaust for that matter.

 

[Kevin Lang]

I keep it under 60 and use cruise control all the time to keep my rpm spikes low.

Under 60 mph?! Do you not drive on any major roads, because otherwise I can't see that being possible. 60 is such a great mph number, a mile a minute. I don't understand why, besides the "rhyme" they went with 55 over 60 as the ubiquitous speed limit for major roads.



According to my ScanGauge II, running the performance tunes I get slightly better instantaneous MPG around 65 than at 60 or below.



Today I just logged 250 miles to Old Rag Mountain (Shenandoah National Park) and back, and according to my ScanGauge's assessment, I got 22.4 mpg. That's including going up all the hills at-speed, instead of dropping to 50 mph or below as all the tiny FWD cars I was legally passing were, and the always-horrendous 495 traffic.



I'm always dumbfounded at these posts about abysmal MPG, as even with a cracked plug & thus misfire under heavy load (so effectively making my ST a 5 cylinder truck) the lowest MPG I ever got was 16.X (don't remember the X) mpg.

 

[Kevin Lang]

Today I had to do an around-town commute. On the way there, I got 13.4 mpg.



On the way back, by going a slightly longer distance (more highway miles;~2.5 miles more), and as such timing the lights & traffic better, I got my total mpg for the whole trip up to 17.7 mpg.



The whole trip was under 15 miles too; it would have been brutal if it had taken me a whole gallon (as it otherwise would have) to make such a trip.

 

[Rodger Tellefson]

I have to somewhat agree with I1tech in that I feel that the CAI only makes the ST sound better. Remove the air intake silencer, get the ZabTeck throttle body & a SCT XCalibrator, put on a single-in / duel-out exhaust. And, step on the gas pedal like it is an egg.

 

[Richard L]

Colder intake air is denser air and denser air requires more fuel. That only means that the computer will deliver more fuel, which can generate more HP, but that certainly does not save fuel. Cold air and free breathing air filters only allow the engine to generate a few more HP at wide open throttle. While driving around town, or cruising down the highway, it will not save any fuel.



...Rich

 

[Tyler Fields]

KL - The school i go to is a 30 minute drive on country roads or a highway depending on the route. My place of employment is also 30 minutes away on a highway as well. Im living out in the country so no where is close. And never in my trac's life has it got over 20 mpg... under 100k miles and has been babied since the day i got it.



Everyone else thanks for the answers! Hopefully i can figure something out before the oil derricks in the mid east get lit up in retaliation for Osama...

 

[Rodger Tellefson]

I am getting around 22 mpg. hwy doing 70 mph. If I slow down to 60 mph I can get 28 - 30 mpg. Keep in mind that those figures are on fairly flat road.

 

[Johnny O]

A CAI doesn't help much simply because the stock intake isn't all that bad. Remove the silencer, put in a K&N replacement filter, and call it good. A cat-back exhaust will get you far more improvement than an intake and doesn't really cost a lot more than the aftermarket CAI's.

 

[Warren Kurtz]

You might be surprised at the results of replacing the stock airbox. We regularly get feedback from members like this:



"Got the Air Intake System for my 2008 4.0L Sport Trac. Finally found someone that made one for it. Air Intake Kit was very easy to install and looks very nice under the hood. Noticed about a 1.5 to 2 mpg gain.



Thanks again for the help and the nice looking kit.



Travis"

 

[Richard L]

Warren,

People spend a lot of time and money on various gagets that claim to improve gas mileage...None of them work, but they will give testimonials that claim fantastic mileage improvements.



My conclusion is that if you spend money on things designed to improve gas mileage, you are also driving to save gas, and that's where the mileage improvements comes from. Most people are not in the positition to scientifically evalute whether any device will save them gas, because they results are skewed by mentally wanting to save gas and the subconsciencely drive a bit more conservatively.



In lab tests done by the EPA nothing that they tested has ever shown to improve gas mileage enough to claim that the device was completely responsible for any improvement.



Some devices have worked on older carburated engnes, but nothing has shown to work on newer fuel injected, computer managed system we've had in todays vehicles for the past 12-15 years.



...Rich

 

[Phil Frady]

The ST is a heavy vehicle, you cant expect it to take off from a stop like a small car does. So, the more you press the pedal to the floor, the more fuel you burn. You would be better off buying one of those electronic gizmos that beep when you take off too fast from a light or hit the breaks too hard. I dont remmeber what magazine sells them.



With my silencer removed and all synthetic oils and a XCal tune for 87, I get on average 17.5mpg. I got 22mpg going to Dallas at 85mph, the year we had the meet there, and that was the last time I got that.



As a side note, if I keep my rpm just under 3K, then I get better mpg. Max TQ is 2700rpm.