K&N Performance Air Filter

[11StiLimited]

Found this filter .

 

Being new to hybrids, but fresh out of the turner world, I have to wonder why the product was even made.  I know K&N filter often add a couple extra HP, but would C-Max even benefit from this?  Like I said, filter/ intake upgrades don't really add much power, but could our cars be more restricted than the average car?  Also, would the new filter negatively impact mpg's, provided normal driving conditions? I rarely stomp the pedal, so the added power would be almost never used. I do think it would be nice to have a little more pep getting onto the highway (altho, I don't have any issues doing so).  In the past, I have used K&N filters for the HP and the fact the are reusable.  I still think having a reusable filter will save me money in the long run.

 

Just tossing around ideas for discussion.  What do you guys think?

[JohnnOhio]

The ICE is one big air pump. Anything that helps it breathe easier improves power and mileage. The air intakes on cars now days are so restictive I'm surprised they run at all.

[JohnnOhio]

Just thought of something. K&N filters use oil to filter air. Don't use them. The oil gunks up your Mass Air Flow Sensor. Use a reusable hi flow filter without oil.

[ScubaDadMiami]

Use a reusable hi flow filter without oil.

Such as . . . ?

[ceemax71]

The owner's manual says the customer warranty may be void for any damage to engine if the correct air filter is not used.

[plus 3 golfer]

Why do people believe the C-Max has a restrictive filter? where's the evidence? and replacing it with an oiled K&N less restrictive filter is of benefit? where's the evidence?

 

If you want more dirt in your engine, put the K&N filter in or any other less restrictive filter. 

 

If you want to save money on air filter changes starting at 120 k miles, put the K&N filter in (3 - OEM filters = 1 K&N filter).  

 

If you want to risk an oiled MAF sensor, put the oiled K&N filter in (of course K&N denies this is an issue with a properly oiled filter).  

 

It's one own choice but beware of seat of the pants performance and mileage improvement claims using a "less restrictive" filter (if there is a restriction, it's virtually always not the air filter) ;)

[JohnnOhio]

I put a hi flow filter in my truck 15 years ago.(still have the same one in there) I got a 5 mpg boost and has 300,000 miles on it now with no problems. Saves gas and only have to buy one over the life of the vehicle. What more could you ask for?

[plus 3 golfer]

I put a hi flow filter in my truck 15 years ago.(still have the same one in there) I got a 5 mpg boost and has 300,000 miles on it now with no problems. Saves gas and only have to buy one over the life of the vehicle. What more could you ask for?

Most aren't going to drive their C-Max 300 k miles and likely not even 120 k miles.  But like I said, go for the savings with an oiled filter if one is going to keep the vehicle.

 

Sorry, but this mileage claim is hard to believe? So, a 5 mpg improvement on a 15 - 25 mpg truck would be a 20 - 33 % increase do to replacing an OEM air filter with another air filter?  Second, modern engines operate in closed loop operation to optimize FE / emissions based on sensor data input.  There's simply no way one could achieve a 20 - 30% FE improvement by replacing an OEM air filter on any modern vehicle unless one illegally modded their vehicle (like removing emissions equipment and re-tuned) and then the FE improvement is not due solely to the air filter.

[JohnnOhio]

Went from 18mpg highway to 23 with the filter change. Use the truck for the farm and it's pulls horse trailers from state to state. After 300,000 miles it only averages 21 mpg highway now(350cid engine Standard Trans). Had a 1992 cavalier until it got Tboned by someone getting chased by the police. It had 327,000 miles on it with a K@N filter. It got 35mpg it's whole life.(2 liter I4 standard trans) Ran like a champ.

[plus 3 golfer]

I simply don't know who to believe! ;)

[hmatthews102]

I have K&N filters in my Miatas and my motorhome.  At the very least I think they do no harm and I do save money over the years.  I usually keep my vehicles for many years, generally in double digits.  I have to wonder though, if FE gains in excess of 20% are available by simply changing the air filter, why wouldn't the car companies put them in at the factory?  Think of the boost to their CAFE numbers.

[Ryan McEachern]

In the past, a restrictive air filter or air intake, could have resulted in the engine running "too rich" which had a negative impact on fuel economy. However, since modern fuel injection, and computer controlled engines have been developed, this is no longer the case.

 

Here is a very general overview of how modern engines deal with air flow:

 

-The computer measures the amount of air entering the engine, and the temperature of that air, and then predicts the precise amount of fuel needed to react with the oxygen in the air to make the most fuel efficient burn.

-Then as the exhausted gases are passing out of the engine they are measured again (sometimes twice) to determine if the fuel is all being burnt, or not

-Then the computer makes fine "trim" adjustments to the amount of fuel being injected until it is satisfied that all the fuel is being burnt, (also, the least amount of NOx and SOx are being produced)

 

As you put on a more restrictive, or less restrictive air filter or intake, nothing happens to your fuel economy, the computer accounts for the amount of air entering the engine regardless of any restrictions. HOWEVER, you can drastically reduce the amount of POWER the engine will produce by restricting the air intake, This happens because the computer cuts back the amount of fuel injected as the air is cut back. If you have a 200hp v8, but only allow enough oxygen into the engine to produce 100hp, then the computer will only inject enough fuel to make 100hp.

 

This is all assuming the engine computer is working properly, and there are no "check engine" lights, and the engine has warmed up already.

[plus 3 golfer]

In the past, a restrictive air filter or air intake, could have resulted in the engine running "too rich" which had a negative impact on fuel economy. However, since modern fuel injection, and computer controlled engines have been developed, this is no longer the case.

 

Here is a very general overview of how modern engines deal with air flow:

 

-The computer measures the amount of air entering the engine, and the temperature of that air, and then predicts the precise amount of fuel needed to react with the oxygen in the air to make the most fuel efficient burn.

-Then as the exhausted gases are passing out of the engine they are measured again (sometimes twice) to determine if the fuel is all being burnt, or not

-Then the computer makes fine "trim" adjustments to the amount of fuel being injected until it is satisfied that all the fuel is being burnt, (also, the least amount of NOx and SOx are being produced)

 

As you put on a more restrictive, or less restrictive air filter or intake, nothing happens to your fuel economy, the computer accounts for the amount of air entering the engine regardless of any restrictions. HOWEVER, you can drastically reduce the amount of POWER the engine will produce by restricting the air intake, This happens because the computer cuts back the amount of fuel injected as the air is cut back. If you have a 200hp v8, but only allow enough oxygen into the engine to produce 100hp, then the computer will only inject enough fuel to make 100hp.

 

This is all assuming the engine computer is working properly, and there are no "check engine" lights, and the engine has warmed up already.

Unfortunately, there are those who don't believe this (or understand closed loop operation) and will still spend significant $ to buy "low" restriction filters (oiled or not) for their vehicles believing FE will increase.

 

Also, to be clear, the possible loss of peak power due to intake restriction is hypothetical for virtually modern cars since the air box, intake, and filter are not restrictive even at peak power (but for a clogged filter). There have been plenty of dynos run using a low restriction air filter vs an OEM air filter vs different intakes, air box and so forth on a modern stock car and there is virtually no perceivable performance benefit from modding the intake but for "sound" - some like to hear that engine / turbo on hard acceleration. :) 

 

The OEM filter and air box are designed appropriately and there is no benefit to modify intakes or filters on a stock car.  If one is worried about air flow restriction from a dirty filter buy a filter-minder like this one and install on your air box.  One will likely get a better return from a filter-minder than a K&N filter as the air filter change interval of 30 k miles on the Ford C-Max is likely conservative.

[armoredsaint]

those kinds of filters will hi-flow more dirt/dust into your engine. don't waste your money.

[F8L]

I put a hi flow filter in my truck 15 years ago.(still have the same one in there) I got a 5 mpg boost and has 300,000 miles on it now with no problems. Saves gas and only have to buy one over the life of the vehicle. What more could you ask for?

Real data instead of anecdotal evidence that is not verifiable. :)

 

The air intake systems on most hybrids is not restrictive and "opening them up" does not increase performance by an measurable amount outside of a lab. Even high performance naturally aspirated vehicle only benefit slightly from a K&N type filter and that usually includes an intake arm or box upgrade.

 

You have to be careful when trying to apply knowledge and experiences from old school tech to new hybrids and their advanced technology. Trust me, after nearly 20yrs of drag racing domestics and selling import performance parts I thought I knew it all. LOL

[11StiLimited]

 

You have to be careful when trying to apply knowledge and experiences from old school tech to new hybrids and their advanced technology.

THIS is exactly why I  posed the question.  All my previous knowledge is being challenged by hybrid technology.  I am not new to closed loop operation and how little intakes alone do for modern engines.  It almost always requires a re-tune, or flash, to see any benefit in performance.

 

I was curious about FE on an otherwise non-modded engine, though.

[jzchen]

The filter you refer to doesn't seem to be correct for US 2.0 L F/I engines anyways....

[11StiLimited]

I was only going by the site's description at the time.  I have only seen under my hood about 4 times in 3k miles, lol.

[slampro]

I don't know much about the K&N filter. However, after 80,000 miles on our Escape Hybrid, we have changed the air filter one time($20). We take it to dealer for all service, and follow their recommendations. Only once have they told us it needed replaced, and that was about 20,000 miles ago.

[ptjones]

I'm going to buy a K&N 33-5001 and Ford FA 1911 and measure difference compared to my 42k old one.

[fbov]

Here's a link to some testing of pressure drops that may give you some guidance on your choices.

Frank

[ptjones]

I've ordered K&N filter and picked up CMAX filter at Ford at lunch time. I've come up simple way of testing only filter using shop vac so we will see how that works. Thanks Paul

[ptjones]

Got my K&N air filter today and sure enough it has less back pressure than Ford air filter. I need to get ambitious to get the old one out, what a pain, so I can test it.

Paul 

[BIG ROCCO]

In the past, a restrictive air filter or air intake, could have resulted in the engine running "too rich" which had a negative impact on fuel economy. However, since modern fuel injection, and computer controlled engines have been developed, this is no longer the case.

 

Here is a very general overview of how modern engines deal with air flow:

 

-The computer measures the amount of air entering the engine, and the temperature of that air, and then predicts the precise amount of fuel needed to react with the oxygen in the air to make the most fuel efficient burn.

-Then as the exhausted gases are passing out of the engine they are measured again (sometimes twice) to determine if the fuel is all being burnt, or not

-Then the computer makes fine "trim" adjustments to the amount of fuel being injected until it is satisfied that all the fuel is being burnt, (also, the least amount of NOx and SOx are being produced)

 

As you put on a more restrictive, or less restrictive air filter or intake, nothing happens to your fuel economy, the computer accounts for the amount of air entering the engine regardless of any restrictions. HOWEVER, you can drastically reduce the amount of POWER the engine will produce by restricting the air intake, This happens because the computer cuts back the amount of fuel injected as the air is cut back. If you have a 200hp v8, but only allow enough oxygen into the engine to produce 100hp, then the computer will only inject enough fuel to make 100hp.

 

This is all assuming the engine computer is working properly, and there are no "check engine" lights, and the engine has warmed up already.

I agree with the above - maybe a less restrictive filter will yield a little more power...maybe...but along with that power will come more fuel burned.

[11StiLimited]

In my case, a shorter burn would be required to climb 3% inclines on my way home from work.  Even a little more tq would go a long way.  Only a side by side hill comparison with a double blind hyper-miler vs standard driver would really show the difference.