I think you're trying to say that you believe the CAI and exhaust you had on your old car were the reason it got such good mileage. The thing is, what you're suggesting is simply not scientifically or physically possible. Like it or don't, believe it or not, there is a different explanation for why the car got such good mileage.

 

Yes, for example the 2nd gens are much bigger, heavier cars with a slightly bigger, more powerful engine. And in the last two years more and more filling stations have fuel w/10% ethanol as part of the mix... guaranteed to drop mileage by 1-2mpg.

Also was the '06 a stick? I'm willing to bet your '10 isn't since only the very base, bare-bones models get the std. That by itself can improve economy by 1-2mpg, or more if driven prudently.
Plus you are talking about mileage per tankful. How many miles you can travel on a full tank.
Are the fuel tanks the same size... gen 1 to gen 2? I'm not sure myself so I'm asking.

But discounting Dale's findings for the moment:
Say you go out and spend the +/-$250 for a high quality, name brand intake. Even if it does improve economy by 2mpg per tankful, how long would it take to financially recoup the cost of the intake?

All things to consider if your only goal for the car is for it to be a DD.

 

Thinking about your post a bit further, I find myself being surprised that you actually think the fuel economy you got from your 4-cylinder 2006 Mazda3 was all that good. The thing is, that car had an eighteen gallon tank (twenty with "reserve"), and even if you short-tanked it and filled at the sixteen gallon point, you were still getting only 27.5 miles per gallon when you went 440 miles.

To my way of thinking, you should have been able to get 32 miles per gallon or better, giving you a "16-Gallon" range of at least 500 miles. Maybe your CAI and exhaust was responsible for your mileage being so poor.

 

27.5 is pretty good for a 6 series, Dale. Even before the ethanol, exhaust sytem and CAI on my car, the best I could average in my 3 series was about 28mpg. And at times, especially during the summer months w/the A/C blasting all the time, I would get as little as 24.
My one time best on one tankful under regular conditions was 30mpg, and I have never been able to duplicate that... though I have tried.

 

Hmmm, I worked with two folks with that vintage of Mazda6, one with a stick and the other with an automatic, and both were routinely able to see mileage in the high 20s with a mix of driving environments; low thirties on the highway. On my Mazda3 I really have to try to get a tank below 30, and a couple of times I've flirted with 40 mpg (although I have yet to hit that mark).

 

hi shipo to clear things up i drove the 2006 mazda 6 for 1 year befor i put the cold air intake on and the exhaust system the best milage i got was 360 to 380 on a tank of gas with out the mazda speed cold air intake and mazda speed exhaust .. yes i do feal it helped milage if you look at how the stock air cleanner is made its main job is to keep the air clean and to keep the intake noise down and to do this mazda chokes down the intake tube on the air cleanner this hurts power out put of the motor .. on the exhaust its job is to keep the noise way down to do this mazda builds a muffler that does not flow very well at all.but keeps the noise down this allso hurts power out put of the motor . i ask you this. why did mazda build mazda speed parts ? . why would mazda make mazda speed parts that would hurt power and milage ? i will tell they would not make mazda speed parts that would hurt power or milage . as for scientifically or physicallt not possible i am a real world person . i will try something on a motor and if it works i will say it works if it dont work i will say it dont work i allway try some things out..to see if it realy works or not . befor i put it down as not scientifically or physically possible take care spencerfvee

 

hi virgin as for the ethanol in the gas thats comming to a end thank god i live in farm country you would not belive how much corn has gone up there is a corn shorttage a fourty pound bag of corn used to cost $4.50 a bag it now cost $10.00 a bag putting ethanal in gas has done more harm then good food has gone up because of ethanol cars dont get good milage because of ethanol . thank god the goverment is stopping the funding of ethanol take care spencerfvee

 

I know the use of ethanol in fuel has caused food prices to skyrocket. But I have heard the Feds are considering an increase in the use of ethanol in gasoline... from 10 up to 15%!!
I don't think it's been ruled on yet, but the lobbyist are out in force from what I've read... and that's not good for us regular people.

I had also read (ready for the irony?) that it still takes 1/3 a gallon of oil to produce one gallon of ethanol. Where are the savings?? And in who's pocket is it going?

Thank you so much, GW!!! Thank you, Mr. Chaney and Mr. Rove for being the main influences.

 

It is a popular belief that a "choked down" intake will hurt fuel economy, and by extension, a wide open intake will improve the fuel economy. The thing is, both beliefs are completely and utterly false (unless you happen to be driving a pre-fuel injection era vehicle).

Want proof? Take a peek at this extensive study done by the EPA which showed no statistically relevant difference (in fuel economy) between a number of engines with their filters opened up or clogged down in varying degrees. http://www.fueleconomy.gov/feg/pdfs/...02_26_2009.pdf

Funny thing in the above study, while the fuel economy variances were extremely minor, they actually favored cars with severely clogged air filters.

You need to separate power and economy; modifications which may yield more usually result in reduced fuel economy (see the study above).

From a scientific perspective, what you tried and then reported on is "anecdotal evidence", evidence that is absolutely and positively irrelevant in the scientific world. That said, when there are enough anecdotal reports, someone or some entity may institute a low level study that attempts to crudely control an environment to see if there is any potential for further study. Evidence that comes out of such a study is typically called empirical or "observed" evidence. If the empirical evidence is compelling enough, then one or more full on scientific studies are instituted, and only then can claims be made as to the efficacy of any given modification.

So once again from a scientific perspective, altering the intake and exhaust of a vehicle to make it flow better has been well proven in the lab (and the real world too) to improve power, however, those same modifications have been proven time-and-time-again to either leave fuel efficiency (as measured by Brake Specific Horse Power which is a measure of how much fuel it takes for an engine to produce one horse power worth of output for an entire hour) unchanged or to reduce fuel efficiency.

 

hi shipo thanks for the tip on clogged air cleanners to help me get better milage. i am going to put 1 LB of dirt in my air cleanner today . i am hopeing to get 40 MPG .. i will report back to you on my scientific findings ..oh my god your funny... i cant wait to tell the guys at the shop about this one ..shipo you have a nice day ..you can belive what you want to about milage EPA air cleanners cold air intakes you have that right to and thats ok with me its been fun talking to you .. take care spencerfvee.