Nice. I haven't noticed a change in my mileage from any mod, positive or negative...21 overall, no matter what. Of course, I don't normally do enough driving to try to do a detailed city/highway analysis like that (don't really care, either ), but if I go on a trip, I'll clear it and see what comes up...got 33/34 to/from the beach the other year.

You know, if the wife didn't mind the intake, you might as well get an exhaust, too .

 

http://www.dailyfueleconomytip.com/u...ur-air-filter/

 

Thats just BAD, completely WRONG information

 

The info is 100% correct. You need to do some research before you call my info incorrect.

 

That's a very old "study". I'll dig up the one that was done this year that proves what I've been saying for years.

 

Click HERE. See the 3rd myth buster at the bottom.

 

Try this: http://www.fueleconomy.gov/feg/pdfs/...02_26_2009.pdf

 

Thats a good find, however the study posted earlier that you referred to as "old" states the opposite. All I can refer to is what I have experienced/ seen and that is gains in the MPG, now ifs that is the result of an "optimistic MID" or "wishful thinking" I do not have the answer. However I am not the only one on this forum, or that has commented on this thread about my numbers being accurate/ comparable to other members, and you dont need to be telling me what i "need to do" before I post.

 

Interesting read, Matt...

I still think fuel economy will be ultimately negatively affected by a dirty filter since you would have to push the car harder to maintain the same throttle response, thus burning more fuel.

 

When you tell me I'm full of crap when in reality I'm right, that means you need to do more research. The whole dirty airfilter equals worse mileage is one of the oldest and most believed myths out there. This was true back in the carbureted days.

 

It won't and the reason for this is you're pushing the throttle further to get the same airflow with a dirty filter than you would have to with a clean filter. The net effect is the same airflow resulting in the same mpg.

The only difference would be with an automatic where the computer sees a larger throttle opening so it shifts a little later.

 

Clearly there have been more that one study on this topic, with contradicting results. Thus I am forced to post the only information that I believe to be true, that information is based on what I have personally noticed based on MY car, with MY driving tactics. The numbers that I have witnessed (which is MY reality )force me to believe that the CAI mod to MY car has lead ME to a MPG increase.-

 

I wouldn't call them studies. More like internet propaganda. Nothing more than someone's opinion posted as fact.

Once you understand how EFI works, both speed density and mass air and the relationship of vacuum, airflow, 02 sensor readings, long term fuel trims, etc, you will realize it is absolutely impossible for a restriction in the intake tract to cause worse gas mileage.

What do you think the throttlebody is? It's an adjustable restriction. Going by the arguments on here you would get worse mileage with a partially closed throttle (restriction) rather than with it wide open (no restriction).

All a plugged airfilter can do is limit full power.

 

^ But if you tell people the truth, then air filter companies will sell less products, then they'll be forced to lay off more people, file for bankruptcy, and send the economy down the toilet.

Oh wait... the economy is already f'd.

 

So wouldn't you end up using more fuel by having to accelerate harder to compensate for the lost power caused by the dirty air filter? I understand the computerized argument, which does make perfect sense. I just would guess that you'll mash out to do what you could normally do with a clean filter, thus burning more fuel.

 

This is very true. I believe the technical term is 'increased rolling resistance'. I installed a Ingalls rear camber/toe kit and then drove almost 200 highway miles back to where I live. My mpg to the install location was 23.9. My mpg back was 27.7. Then I aligned it later that day and the mpg raised a bit more. I'm a very happy camper now.

 

No, because you're mashing down on the accelerator just to get back up to the same airflow as you were at with a new filter. Total airflow is the same so no extra fuel is used. The pedal only controls the airflow. The computer matches fuel based on airflow, not throttle position.

 

Yea, that does make sense. Hmm. So, are you saying a dirty air filter causes just a decrease in performance? I was always taught differently but everything you said about efi is correct. ....*ponders away*

 

It took me a while too. I had a ton of "ifs" at first.

With a carbureted car, which is where this originally came from, a dirty air filter increased vacuum through the carb which made it run rich and decreased fuel economy. This myth carried over to fuel injection unfortunately.

 

I just figured the extra compensation of opening the throttle to get the restricted air unrestricted would result in more, unneeded combustion. But everything you said makes absolute sense. I'm going to talk to a few people about it because now I'm curious.

I never did see how a cai would save fuel. If you consider a blown motor, you have to use more fuel when you accelerate to mix with a higher flow of air. So, besides a nice increase in power, I didn't understand the higher mpg claim.

This is an interesting subject.

 

^I agree with above poster. I do mostly city driving and best I could manage in my TL was around 22/23 city driving pretty conservatively. That didn't change after CAI.

 

Thanks "I hate cars." I always thought a CAI would improve fuel economy. But clearly it does not from your strong evidence. Even in the original posted study (comments section) there is mention that the data is from 1981. I had to read your study over a few times to understand the concept that stepping on the gas pedal controls the air..which then controls amount of fuel..not the other way around. correct? haha. still not sure but I think that's right. nevertheless thanks for clearing the concept up for me. I was almost considering a CAI for fuel economy. I don't really care too much about the "iffy" performance gains. I guess I'll pass on it now.

 

For what it's worth, when I got my new wheels and Tires (A-Specs & Goodyear Eagle GT) my Highway (65-75mpy) MPG went from around 29 to 32. I also got a 4 wheel alignment, and I had the tires filled with Nitrogen, so that may have played into it. Even with mixed, "spirited" driving I get aorund 22mpg all-purpose.

 

Proper inflation and a good alignment (just recently) gave me an extra 4 mpg. I was shocked but it makes absolute sense. If all four corners are even (with correct psi and alignment), then the car isn't 'dragging' extra weight. I don't think the nitrogen itself is saving fuel over regular oxygen, it's just that it supposedly keeps the tires around the correct psi because the molecular structure is less able to exit the tire. ....or something like that. Hah. I read about it before. Very scientific stuff.

 

I get round 20 city n bout 28 hwy.

07 TLS w/AEM CAI 6mt