Im wondering what the pros and cons of adding a cold air intake are to my car.

2003 honda accord ex 4dr/cyl 107k

is anyone experienced/familiar with these?

All i can seem to find is better gas mileage, and a possible increase in value, just not sure if its worth it.


Any suggestions?

 

A slight bump in gas milage and throttle response. More noise. Do not trash your stock components when you remove them.

If you sell the car and a soccer mom is interested in it she will most likely not view a CAI as extra value.

 

It isn't scientifically possible for a cold-air intake to improve fuel economy, in fact, they often lead to reduced fuel economy, especially when the outside air temperature is lower than forty degrees.

 

can you elaborate? Colder air = more density which equates to more combustion hence the CAI. Is there a threshold?

And wouldn't it be scientifically possible for a CAI to improve efficiency if it is reducing intake drag?

 

What you've written is a common (and oft repeated) misconception of how engines (specifically closed-loop fuel injected engines) operate. Last August I started a thread here which addresses this misconception; the discussion (and your requested elaboration) can be found here:

• https://www.hondaaccordforum.com/for...l-truth-49964/

 

Interesting read, thanks for the link. I have a bone to pick though.

These test were conducted at WOT which only samples a small portion of our driving habits. And yes I can understand the physics and math behind it, it does make sense that under WOT there is no appreciable difference on injected obd2 cars.

However the test fails to take into account the power difference by only focusing on WOT situations. It does state that acceleration times are faster when the filter is not clogged but (unless I missed something drastic) they only measured the MPG rate during WOT conditions. So both test use the same amount of fuel under WOT just that the unclogged filter test is using it for less of a durration, in turn using less fuel to achieve the same desired result, cruising speed.



Instead of a lab test let me put this in more of a real world scenario (where some times these seemingly minor oversights can be circumvented). I had turbocharged my Accord about 3 years ago. I was putting down 230 ish WHP and used a far grater amount of fuel, over stock, to achieve that number.

However my Highway milage went UP from 28-29 to 33-35 (and I keep meticulous records and graphs of my consumption) This happened overnight and the reason is the same (only more drastic) as listed above.

More power meant that I was not on WOT nearly as much as I had been with my NA engine. I could climb hills at a quarter throttle in a high gear instead of flooring it and downshifting to the lowest possible gear. On the flip side I did see my city milage plummet as it should, thans to many stop lights and a lead foot.

So I appreciate the studies and knowledge shared but you must also accept that scientific testing is subject to oversights that can flaw the data.

This test proves the laws of nature in a test tube like scenario. However it fails to understand that an increase in power can lessen the need to use it, aka using WOT for less time which CAN reduce fuel consumption. So I'd say it is "scientifically possible" for CAI to increase economy.

 

Calculating miles per gallon at wide open throttle is not a valid metric. Why? Because at WOT the engine computer switches to "Open Loop" mode and runs the mixture full rich, hence the fact that you might get a bit more power at WOT.

In your case the CAI had no impact on your fuel consumption, the reason why your MPGs went up is because of the turbocharger. It is very common for turbocharged cars (both from the factory and aftermarket applications) to yield better fuel economy due in part to the warmer intake mixture (which aids fuel atomization) and the longer intake runners (which changes the intake resonance which also in turn aids fuel atomization).

The above said, I will repeat it again, it is not scientifically possible for a CAI to improve fuel economy in a modern fuel injected car for the very same reason that a horribly clogged air filter will not negatively affect fuel economy. Long story short, you cannot fool the MAP/MAF sensors, they know the weight of the intake charge and meter out the fuel accordingly; X pounds of intake air will yield roughly X/13.x pounds of fuel being metered out by the fuel injectors.

 

Ok, soooo you disagreeing with me that by increasing power and reducing the time that you have to use WOT one can use less fuel in the long run therefore increasing efficiency?

I'm sorry if you don't care to acknowledge this fact, that fine with me. But however small the difference may be it is still a difference therefore debunking your "scientifically impossible" statement.

Oh and I have to WOT almost everywhere to get up to speed here in colorado. BMW made a series of 3's called the e series. They built low reving high torque motors because the smart people at BMW realized that to get the highest MPG rating it was advised to accelerate (~75% throttle) to cruising speed instead of slow drawn out accelerations. I tend to go farther than 75% because I don't have the power of a BMW and don't like to merge on to 75mph freeways at 55mph.

 

Seriously, look at the data, if what you say is true then the cars in the EPA test with the clogged air filters would have gotten worse fuel economy and they didn't, they got slightly better. Trust me, their tests are far more controlled and repeatable than anything you can do.

 

Shipo,

I don't care about what their test says in my opinion it is a flawed test.

They failed to calculated the difference in time (and fuel) that a car is at WOT for to achieve the same result, speed.

Had they calculated the amount of fuel saved by faster acceleration and then incorporated it into their findings I would have more faith in their "Scientific Test".