Did you not read the part about more restictive = better fuel economy?

Warm air requires less fuel to burn than cold air.
Less air volume requires less fuel to burn.

CAIs do not improve economy in any way. This is a well established fact/. Further, adding a CAI alone does very little, as it only modifies one very short section of the intake tract. The TB, IM, and valves are all untouched. The CAI can't magically force more air through them. The only way to do that... is to actually force air through them. You know, forced induction. Which also doesn't help mileage, as the S/C equipped folks will attest.

 

Did you read my above post at all????

If the engine gets less air, it burns less fuel, period. A restrictive filter/intake does not hinder fuel economy, that is a tactic that part manufacturers and cheap @$$ shops use to sell the unknowing parts and service. The engine physically cannot burn more fuel due to a restrictive filter, because it cannot add more fuel!!!

Your ECU will keep your car as close to stoich (14.7:1, the ideal balance for economy, performance and emmissions) no matter what you do to it, besides adding fuel management. If you ran a turbo without fuel management, the ECU would do anyting in its power to keep the A/F ratio the same. So the more air you add, the more fuel it adds, period. This is automotive basics.

And to say this is "not physics" is completely off.. it is 100% physics.

 

Here is a good analogy to help you understand:

If restricting the air passage makes for poor mileage, than the car should burn obscene amounts of fuel while running with the pedal barely depressed, and should get amazing economy while running 100 mph with the throttle wide open. we all know that is not the case. And all you are doing when you depress the pedal is opening the throttle plate. that is it.. nothing else, you are allowing more air to enter the engine. The ECU sees this and adds the fuel itself.

 

Hi,

Thanks for all the reply to my questions. To people who claim that a CAI doesnt add HP and mileage due to their understanding of physics, this is all just a hypothesis right? As in all hypothesis, it must be proven correct, not just based on theories. Has anyone who says it wont help, based on physics, actually installed a CAI in their car and taken a meaure of gas mileage and even HP (though that might be harder to measure) compared to the control, that is with stock filter?

 

Yes, I have. And I actually saw a decrease in mileage. But, only a couple of mpg, so just as in his result, is washed out in the other variables. And once the butt dyno is over being fooled by noise you realize that you see no difference in performance, especially when you have swithced back to stock. That is exactly what I did, so I have run it stock, then with a CAI and then stock. The fact that I pretty much saw no real change in mileage (and definitely none positive) or performance pretty much backs up what I am saying.

 

Thanks for your reply, I guess there would be no real way to test it unless you have some kinda wind tunnel or something. But I would think even with all the variables, with enough sample size, say, at least 10 fillups on the same routes, which I think lots of people do from work everyday, it would decrease the effect of other variables and get a somewhat statistical relevant analysis.

I wonder what those people at injen base their 12hp increase on (which is theoretical and wont happen in real driving conditions) but I would think they cant advertise hp increase and not get sued for false advertising. Once again thanks for trying to explain how the CAI would or wouldnt work, I am just trying to do more research on this and trying to figure out if it really works.

 

^^ The same way the shops advertise the same gains for a crank pulley, which does zero to make more hp. It simply reduces rotational mass, which , once the engine is in a steady state (static rpm) is not going to add hp. IT is all how they measure it and how a dyno responds. You obviously will notice a 12WHP gain.. but I can tell you that once I replaced my cai with stock again I felt no effect at all. The other thing is where they saw a gain.. if they saw a 12WHP gain within a 10 rpm span somewhere in the range.. they can still advertise that, and you wont feel a thing. People just get stuck on Peak gains and forget that peak means almost nothing to how a car performs.

I also ran my CAI for about 2 months of everyday driving and some travel. It snapped the bracket after a month, and I ended up taking it off about a month later.. a couple of weeks more possibly. I cant remember off the top of my head, but I believe I ran it for about 12 tanks of gas including a couple of trips. In any case, power was only affected a minute amount if any, as was mileage (and only a negative amount anyway). The two co-incide. If I would have seen a big power gain, I would have seen a larger drop in mileage. There really isnt any way around it unless you can physically make the car burn fuel more efficiently, which an intake has zero effect on.

 

No matter what you guys say since installing my intake I have gone from 28mpg to almost 31mpg.
I drive the exact same way i did before. no harder no softer.
Dont argue with me call me naive, but it has helped my mileage.

 

^^ Then that means it's making less power. Because it's one or the other. You don't get both.

Perhaps the horrendous heatsoak through the aluminum tubing is letting the ECU use less fuel to burn the heated incoming air. The "HAI" principle.

 

How many miles did you have when you put the CAI on? My mileage slowly increased as the car was broken in for the first few thousand miles. First 500 or so miles it was about 25 by about 5000 miles it was up around 30-31.

 

One of those intakes that claims double what the others are getting was tested with an exhaust and other things too. It said so in the small print on their page but I dont remember whos it was.

 

If you think driving around with a restrictive filter will get you better gas milage then do it! GO right now and rap your airfilter in a t-shirt and then put it back in the air box. Then fill 'er up and see how your gas milage is.I bet you'd get 18mpg at best, and your car would be slow as crap. Because you would be putting pressure on the engine to suck in enough air to keep running smoothly. It's like kinking the vaccum hose. It doesn't make it use less electricity, it makes it work harder to pull the air in. When you install a CAI it releives some pressure from the engine and allows it to breath easier. We could argue this all day but I still ask the question... how can you argue with the numerous people who have installed CAI and report better MPG numbers? I put my CAI on at 17,000 miles and saw an increase of 2-4 mpg in the city (i rarely get on the highway).

 

Engines don't suck in air. Air simply moves from areas of higher pressure to areas of lower pressure. Learn your fluid dynamics before you mentally murder a physicist.

The whole kinked vacuum hose/electricity analogy is... mind-boggling.

 

^^ yeah.. in no way whatsoever relates to an engine.

So, restrictive filter... engine cant pull in air as easilly right? (this is going by your analogy)... guess what that means? IT CANT BURN MORE FUEL. Your analogy is a circular reference.

A better analogy would be if that vacuum ran off the air it pulled in.. now.. would it use more or less "fuel" with its intake kinked?

As Dr I mentioned above.. you really should look into more physics on this.

 

I hate to break it to you, but the reason you saw an increase in gas mileage was because your filter was most likely dirty

I replaced my air filter from the stock airbox @ 10k miles. Saw around 24mpg in the city. I put the CAI @ 11k miles, and now i see around 22mpg.

If the stock intake is *so* restrive, then adding an aftermarket intake should yield a lot more power, but it doesn't. There is no way, that toyota, a car company partially based on fuel economy numbers, sell a car with an intake that isn't getting the best gas mileage it could.

So my question is - if it adds horsepower, and improves fuel economy, why didnt it come from the factory that way?

 

^^ And why havent they gotten a nobel prize for re-writing the laws of physics?

Again, the only way to improve power output of a vehicle without harming fuel efficiency is to either remove loss from the drivetrain, remove parasitic drag on the engine or make the car burn fuel more efficiently. An intake does nothing for any of that. Sure, it may seem that is makes it easier for the car to "Suck" in air (which is really not tha case), but for every air molecule that is added, fuel is added. The whole premise of the intake is that it allows the car to burn more fuel at once by allowing for a more dense charge. You cannot argue that.. it is the facts about why they are supposed to deliver more HP. So I still want to hear how it can accomplish this and still not burn more fuel... is the intake magically leaning out the system? No.

 

Exactly. Concision at its best.

 

Easy.. its because those aftermarket comanies know worlds more about engine design than, say..... guys that design engines for a living for toyota At least that seems to be the consensus among many "tuners". Hell.. the turbonator avertises more hp and mileage... why doesnt everyone believe them as well... it says it right there on the add right???? Oh wait.. its because those dont look and sound cool :D

No offense to anyone, I think a CAI looks great and sounds nice.. and if you want that, go for it.. I just hate to see people spending money on false hopes of these magical physical phenomena

 

Dont get me wrong I didnt buy the intake because it said Id get better gas mileage, I got it for the sound/look. The fact that my mileage seemed to go up after installing it is just the cherry on top.

 

I will also attest to my mpg going down after the intake install back when I was n/a, albeit not a DRAMATIC amount but it decreased none the less.