(now brand suggestions for air intake and exhaust) gas mileage help

[Astar24]

hello everybody
i drive a 2001 explorer sport, and lately i noticed that the gas mileage performances have gone down a lot. i believe they should be around 15(city) and 20(highway) MPG, and they are not. even if they were not that good before, i still noticed a difference in the last month. i had a complete check by a mechanic some weeks ago, and he cleaned the fuel system too, which is supposed to improve the mileage (correct me if i'm wrong), but now it's worst than ever.
in conclusion, what can be the problem?
extra question: i heard about those air intake modifications that can save some gas. do they work? and what is the negative side of the medal?
thanks a lot for the attention

 

[redneck21]

I seen a good bit of question like ur pop up. Every ting in fine with the car but bad gas millage. Alot of pace are now adding 10% ethanol in the gas witch will give you crappy MPG. wear you get ur gas from? I know ALL the shell stations in and around Athens GA do that now. Fill up from a different and see if that don't help also look all over the pumps to see if it might have a sticker on it saying it has it.

 

[Shen2187]

The 10% Ethanol blend they are running at most fuel stations, will give you worse MPG, and you may notice your engine lose a little "umph" for the simple fact that Ethanol does not ignite as explosively as Gasoline.

(Just an addition, I've not noticed the Ethanol blend burning any cleaner, I think they just wanted to hush the crazy environmentalists for a while. Don't get me wrong, I respect nature, and do my best to clean up after I've been somewhere, but there is a line and alot of these nutjobs cross it with ease.)

Extra Answer: A free(er) flowing intake system will, in most cases, give you a MPG boost.

A free(er) flowing intake system will allow more air into the engine, faster. With the sacrifice of a little noise. Allowing the fuel to ignite faster, hotter and efficiently.

A free(er) flowing exhaust system will help in conjunction with the intake allowing the exhaust to escape more efficiently with the addition of yet more noise.

It's all about Efficiency vs Noise

 

[Astar24]

thanks shen! sounds like a good compromise to me. since i'm not looking for performance in torque or hp, but more in fuel efficiency, can you suggest me some good brands for the intake and the exhaust?
thanks

 

[chetzar]

K&N Cold air intake and a flowmaster exaust ftw.

 

[Shen2187]

Not sure what is available. for the 2001+ X's.

Flowmaster is great if you want a mild performance exhaust system.

K&N and Volant have great mild performance CAI (cold air intake) systems.

You WILL get performance increases, but you will also get MPG increases. (Along with a nice sound ) Because, the cooler denser air, and more of it, will mix better with the fuel. This will cause the fuel to burn faster, hotter and more completely. This is where the exhaust system kicks in and removes the exhaust from the engine and away from the vehicle, faster and often times, more completely. (Forgive me if you've heard this before, if you have, ignore it.)

Your MPG will increase because the engine does not have to work as hard to move the weight of the vehicle.

Also a higher octane fuel can help with MPG, but the cost out weighs the MPG increase easily. We're talking fractions of 1 MPG here. (Just fair warning if someone tries to tell you otherwise.)

 

[Astar24]

shen you're better than wikipedia to me last question (i promise): my car has 85000 miles, would it be necessary to change the whole ex system, or only the muffler (that fat thing) would be enough?
thanks everybodyfor the tips. seems like flowmaster doesn't have a specific system for my model, any other good brand alternatives?

 

[Shen2187]

Hehe, Thanks.

Your exhaust system should still be in pretty good shape after 85000 miles. Unless it has "lived" in a high rust risk area (coastal areas, or high humidity areas)

I still have the factory system on my 1991 XLT (268,000) only problem with it is a hole in the muffler, and the internals of the cat have probably collapsed by now.... (I should probably check that XD) Just to put the possible life span in perspective.

 

[Astar24]

that's what i was thinking.. 85000 miles all in Miami :S not exactly a dry place. I think i should change the muffler.
I just noticed that along the tube that runs from the filter to the engine there's a thing that looks like a computer, with some cables. is that some sort of sensor to determine how much air is going to the engine, and thus regulate the amount of fuel? in that case, if i swap the stock intake with the aftermarket one, what should i do about it? is it still going to be compatible with the new filter, or not? i don't want the cpu of my car to say "oh no, there's no air going through the engine" and #### it up really bad in some way that i don't even know..
i hope you got my point

 

[Shen2187]

That is more than likely the MAF sensor (Mass Air Flow) Which detects how much air is going through the pipe. The new intake tube should allow a hole to remount it into. So it should be just fine.

 

[Astar24]

cool, that's what i needed to know.
thanks!

 

[Shen2187]

No problem.