Crazy how much conflict there is over something so simple, it seems this would've been brought up and proven fact or fiction a long time ago. Somebody with access to a dyno for no cost needs to get bored enough to do before and afters of simple mods like this and make an archive.

 

DON'T CALL ME FUDGIN' CRAZY!

 

It is well documented that replacing stock aspiration with high performance parts increases horsepower, torque and fuel efficiency. The sacrifice is noise, comfort and durability.

I am paraphrasing a well-written article that appeared in Tuner ® magazine about three years ago.

First they lead by writing that the reason that commercial airliners fly at 35,000 feet is that the air is colder and dryer at that altitude. The fuel savings are enormous and they have performed extensive studies to that effect. Their physicists know that cold air is denser and produces more efficient combustion. Cold-air intakes offer this advantage and more.

If you were to take a stock intake and exhaust on a Honda Civic and replace it with Cold Air Intake, light steel headers, aluminum cat-back system, switched to low profile, light alloy rims, you would save about 75-100 lbs. Increasing the diameter of the tire, adding higher air pressure, low profile tires, creates less rolling resistance and fewer tire rotations per gallon; better MPG, more strength to weight ratio.

They took 5 commonly modified cars and measured the effects of individual mods.
1. Cold-air intake/intercooler/short ram
2. Headers
3. High-flow Catalytic converter
4. Cat back system (with muffler).

The cold air intake alone added about 8-10% Horsepower and 5% fuel economy. With all the above mods, the results were 15-20% in horsepower and 10% fuel. Each car varies a little. The only car that it did not improve was the Subaru WRX, apparently the WRX is already tweaked out of the box with the intercooler, exhaust, etc. Quality manufacturers like AEM, DC, Borla et al, do extensive research and testing to determine and create the best match for your application. CAI are not better in all cases. Some cars perform better with short ram.

The article explained the following:
First, aftermarket parts normally are a great deal lighter than OEM parts. Aftermarket makers, with racing in mind, use lighter metals. Reducing weight lowers the pull on the engine, this increases MPG. A focus on airflow reduces strain on the rings drawing air in as needed and blowing the spent exhaust out easily through tuned headers, fat cats and wide pipes allows the engine to “breathe” more efficiently, greater MPG, greater HP. OEM places a high value on quiet comfort, durability and serviceability. They use heavy iron parts, thick polymers and stronger than needed steel. They do this to avoid recalls and consumer advocacy at the sacrifice of performance and efficiency. They must warranty the exhaust systems, sometimes for the life of the car. They are not appealing to racers, but rather homeowners and commuters. This makes sense. However, if you are reading this article, you are not the kind who minds a little more noise, a stiffer ride and a little more effort for an increase in performance in all aspects.
The article is punctuated by the following statement. Although these mods improve fuel economy, any advantage is likely to be negated by spirited acceleration and high speed driving.

The article sums it up by saying “aspiration modifications are the cheapest and quickest ways to increase horsepower and fuel efficiency.”

 

wow...getting angry over a lil filter?

now on a CAI it still has to go through a HOT pipe before it can get to the engine. how cold is the air after travelling past a burning pipe?
even SR's are behind a headlight that isn't air tight. still fresh cool air.

my SRI hasn't noticable increased or decreased my mpg.


and OEM owns aftermarket. less array of parts but better quality. how many people do you know can say they've been running any aftermarket part for 15+ years?

 

Funny, just happened to me as well. I just told my dad that I wanted to hear vtec crack, and he rode with me and was proud. Haha.

 

I have a short ram-intake. With K&N Filter on it. I notice more power and the gas mileage is the same, great! Hello people we drive civic's here. Who cares about ten click's less to a tank we still only pay 35 bucks to fill it up lol.

 

^ I agree with the above statement. Rolling an ebay intake with K&N filter and not cat I noticed power on my stock civic. Not much but it was only because one part of the freeway that goes uphill my car would constantly decelerate in 4th gear (auto) until I got passed it, after cai it would stay going whatever speed I was in and the gas mileage is the same. Going manual b18c1 now though so we'll see how fun that is lol

 

Anyone who slaps on an intake and thinks they can tell a difference it retarded. You are getting a few HP at best. Not enough to ever notice. The guy who thinks his car lost 3-5mpg with a short ram must not know how to add right or drive consistently.

 

I didn't notice anything when I bolted that crap on except that it got louder. The little horsepower you gain doesn't make one bit of difference where it counts. I also didn't notice any real increase/decrease in mileage.

 

I question how scientific most people tests are that determine these fuel
economy numbers. Everyone drives differently every time they get behind
the wheel. It's impossible not to.

 

It's impossible to drive your car the same each time. IMPOSSIBLE!

Unless you are in controlled environment, doing the exact speed with the exact same RPM each time. With the exact same weight temp, gas, etc. Any change in those has the ability to affect MPG.

City street/ highways aren't even close to a controlled environment.

Why would I say i lost MPG if I didn't?


Whether I lost MPG for some other reason, who knows. I don't? But I am not going to say my intake had nothing to do with it, because I have no proof to show other wise.

There are so many things that can affect gas millage, hell, maybe the addition of my subs/weight of them affect the MPG. But until I see factional proof that short rams increase MPG I will disagree.

The short ram 'may' be going back on soon. If I do put it back on I will again run 3-4 full tanks threw it and check the MPG each time.

 

theres plenty of resources to find an answer other than starting this thread, like try to find some dynos on google or the dynos link posted earlier. all this thread accomplished so far was peeps arguing about whose experience is right or what scientific "facts" are correct.
/thread

 

I got links to dynos for bolt-ons. Check Section 4 of the FAQ.

 

Well i am taking physics in school right now and most of what sabjork said is correct. There is less oxygen at 35k ft above sea level but the air that is up there IS denser and causes better combustion. But then again we are talking about a jet engine compared to a combustion engine which are very different as in size, fuel economy, and mechanics.

The average jet engine uses 150 gph. But then again it can transport about 250-350 people. Depending on the plane. Also take into affect the airframe is made to travel through air currents that affect the entire airframe. Enough about air planes. I crunch enough numbers every day in school about that kind of stuff.

Adding a cai AND headers is optimum. You cant expect more air to come into the motor and have a denser combustion which produces more power and has to be expelled through the exhaust without increasing its flow out of the motor. So in saying that, adding a cai and keeping stock exhaust in my opinon, will only increase power by maybe 1.5% to be more exact. Wont really affect fuel economy because the computer compensates by making it more rich to run to factory specs. Im not a genius but i think its pretty common sense(most people lack that nowadays) that a cai probably only has noticeable gains for fuel economy in every 3 or so tanks of gas if you want to keep track of your fuel economy that closely then it sounds like you are a penny cruncher and get value for every buck you spend. More power to you.

Remember that we live(most of us) in a free market society where the more consumers spend the higher the capitol growth of the nation all together and the more we each as a consumer benefit. I am leading off topic so i will sum up saying that YES you gain fuel economy with a cai. YES you have increased power. Even on a minute scale, it is increased. NO its not as durable as OEM because it is not as resistant to wear and tear. The good comes with the bad. Either way you look at it. We could debate this to the end of time or we could accept the fact that everyone has an opinion. And everyone is right in their way of looking at things because we all look at it differently.

So if you want noticable gains that are not on a minute scale... Turbo that mf'er and to hell with the fuel economy. Iran and china are going to become rich from us either way because we have gone from an industrial country to a lazy pack of politicians that knows whats good for the consumer. My opinion on the matter. And this is short compared to the exact details i would like to put but ive been typing for about 15 minutes and want to check out more threads Good luck to you all on this debate. I wish people could just agree to disagree more and leave it at that.

 

do you happen to be taking a writing class too? sheesh!

The OP wants to know about mpg, not hp. any time u add air w/o adding fuel u are throwing ur a/f ratio off, therefore decreasing efficiency. I took a lot of physics in HS and college and didn't need any of it to say what I just did. But good job putting ur learning into action!

 

I have a few thoughts on this one...

My mileage changes by 1-2 mpg every time I refill, and I drive the same route to and from work at about the same times every day. I could tell you that my driving style is always the same, but I would be full of ****, which is the case with 99% of people on here. To keep your driving style the same, you need to really make an effort, and you'll need to monitor TPS, MAP, and RPM. Even then, there will inevitably be variation.

To improve fuel economy, the trick is to keep manifold pressure as high as possible to maintain the same power (but without going into enrichment). When manifold pressure is higher, there will be less pumping losses, combustion duration will decrease, and you'll need less timing advance for MBT. Keeping this in mind, warmer air will require more manifold pressure to produce the same power, which is inherently more efficient. The opposite is true with colder air. Colder air will just make more power at WOT.

Also, as you all probably already know, if you're concerned about fuel economy, the assumption is that you're running in closed loop, so you will always have a near-stoichiometric mixture. Therefore, installing a different intake will only affect mixture strength in open loop. If you've disabled oxygen-sensor feedback so you can run lean on purpose, that's a slightly different case. In fact, running lean improves fuel economy for the same reason that hot air does; more manifold pressure is needed to produce the same power.

However, there is an exception. If your engine is knock-limited and you have to reduce timing below MBT to prevent detonation, your thermal efficiency and therefore your fuel economy will drop. This is more applicable to cars equipped with knock sensors.

Those of you saying that you lost power with a SRI due to the loss of low-end torque - did you open the throttle more or shift higher to compensate? If you shifted higher, it's no surprise that you got worse fuel economy. Less engine speed and more throttle will (generally) result in the lowest BSFC. Less (or the same) throttle but with more speed will (generally) decrease fuel economy.

Regarding the airplane analogy, the reason fuel efficiency improves at higher altitudes is because the air density is lower, which reduces drag. If you have less drag, you don't need to produce as much power, which means you don't need as much fuel to maintain your cruising speed. It has very little to do with combustion.

 

it will def add more power and mor eMPG as long as your foot has not gotten to heavy..lol

 

thank you ddd4114

 

I'm sure your driving is as inconsistent as your "experience and fact". For someone who was making sure everyone knew he was speaking from so much experience and preaching the word of fact you sure changed your tune and did a 180.

 

Haha.. Writing, math, social sciences.. I love most of it. Learning intrigues me. I believe i stated that there are only noticeable gains that are beyond minute after you keep track of 3 tanks of gas. Not to offend you in any way by trying to correct you on my statement. I can see where i got too broad on the subject and didnt stick to the main topic. Something every english teacher criticizes me for but when i look at the box, i check out every 90 degree angle, the width, length and sometimes go beyond to say its a triangle!! I love debates. Debates that are resolved without pissing all over eachother. Where does it get everyone if they just wanna go around pissing on eachother about all of their differing opinions? Here i am going off topic again. So again... in my opinion and i know it may stink but i love the smell of it, Yes there is a minute gain in the short term and a bigger gain in the long term not being cost effective bacause the units will have to be replaced because of wear and tear. I believe OEM and after market both have their advantages and i pick after market because i like louder engines along with faster acceleration to that 60 mph mark. For safety reasons of course :p haha

 

He was throwing a hint that you need to learn what the enter button is and create paragraphs instead of one huge wall of words.

 

Also allow me to state that in my opinion, companies that try to sell you the intake based off fuel economy is pretty much a scam because they are misleading you by not telling you every aspect. Down to the bottom line, performance is not necessarily about fuel economy and hondas are some of the most fuel efficient cars on the market. 99% of people that buy a cai buy it for performance before they buy it for fuel economy. Fuel economy shouldnt even be brought up this much when it comes to performance parts because in the long run you are going to spend all the money you save either way it goes. Probably will spend it on replacing the product after it is worn and outdated.

Ive been waiting for the automarket to come out with some kind of pressure regulated oxygen tank that you can hook up to your intake that boosts fuel economy and adds performance. Note how i said it like the manufacturers would say it. By boosting fuel economy first and then adding performance. But then again you would be spending money on the tanks to be refilled every week that you "saved" on fuel economy. I might just invent me one of these products and become a capitalist millionaire and then when i get the money ill outsource my labor like all the other good american companies do. Join the movement as they say or be left behind. Well this country joined a movement that left itself behind.

 

The stock intake sucks are from under the passenger's side front wheel. The stock intake is basically a CAI with a U-trap to keep water out and a resonator to keep the noise down.

 

Sorry. I didnt think this was a writing class and that i would be graded for my use of paragraph structure. But before those panties of yours get all bloodied up in a wad, i will keep that in mind and pay respect to those of you that cant follow along and get confused with which line you were on.

Thank you for dumbing down what he said to me to make it clearer. I will edit my posts and create paragraphs.

 

Damn we got some authors in here.

Who would have thought a pipe with a filter could cause such a debate lol