I understand cool air makes more power, fuel has to mix with air correctly and there is a balance between turbulent and laminar air flow. That being said, with all the money that Dodge, Ford, Chevy.... put into designing there vehicles, wouldn't they put the best setup in there vehicles as far as the fluid flow design of the air box goes. Maybe a K&N filter in a stock air box will flow better than a stock filter in the same location. It is real expensive for dodge to produce trucks with stock K&N's vs. there stock filters.

So, do these fancy air boxes I see everywhere do anything to increase HP? I really don't see it happening. Unless you have a true ram air setup from a hole in the hood. Does K&N or AirRaid have more money to spend on air box design? I really do not think so. Especially since they produce parts for nearly every vehicle and manufacturers concentrate on the design of there own stuff.

I guess this is kind of a rant, I just think all of these air boxes are kind of silly. Such a waste of money for the poor uninformed people, unless of course I am completely wrong about this.

Money could be much better spent on something else for your vehicle. Like a few tanks of gas.

 

The factory has a few things in mind when they design vehicles.
1) K&N's require attention. You have to clean and re-oil them. If you over-oil them you can screw up your MAF (if so equipped). How many people are running around with clogged paper filters? How many of the people who actually get their filters changed would actually clean and oil a K&N properly?
2) Filtration - K&N's don't filter as well as a paper element. They allow larger particles through. Manufacturers don't want to deal with failures caused by it. The oil is supposed to capture the particles, but if you don't keep it oiled...
3) Noise - Stock air-boxes are designed to reduce the resonation and noise coming from the intake side much like the muffler eliminates a lot of the noise from the exhaust side. If the manufacturers were really concerned with all-out power and fluid flow designs, our vehicles would come with straight pipes from the factory.

But if you're the type who changes your own oil, rotates your tires, and doesn't mind increased NVH, there are products out there that will increase power and noise, such as high-flow cats, mufflers, and intakes.

 

I have to agree that the only way I can see a HP increase would be from a Ram Air type setup. I'm pretty sour on the whole cold air intake systems as where is this "cold air" coming from? The last time I checked, it's pretty hot in a running engine compartment and the location where the stock air box gets it air flow from isn't enough. I used to have a cold air intake on my Jeep Cherokee Sport with the 4.0L I6 and it made no difference to me at all. As a matter of fact, the cold air system with an aftermarket cat back exhaust did nothing for me powerwise. It wasn't until I put a bored out throttle body in that I noticed any difference in power. Some members of the Jeep forums I used to visit did mods to run tubes to a cuout they made in the front grilles to try and get that outside air in. Luckily the tube system I had was only $60.00 (Rusty's Off Road). These fancy schmancy K&N styles setups that are $200+ offered nothing additional over what I had except for the heat shield.

Check out K&N's HP claims for their system for the Hemi. 10HP increase but at over 5000 RPM. Who the hell drives in that range? The only system I read about recently that seemed decent was one by a company called True Flow. They use an oiled foam filter instead of an oiled cotton filter like K&N does and the magazine I read about this in installed it in some GM SUV and they dyno'd it to show a few HP increase at a low RPM range. That seems more promising but in something like the Hemi, wil you really notice 350HP over 345HP in normal driving?

Having said that, I did install a K&N filter into my stock air box inmy '05. I liked the one I had in my Jeep before I ditched the whole air box for a tube/K&N conical filter, not that it gave any power increase at all but I did like the fact that I didn't have to replace the filter and I thought it was pretty easy to maintain and I was diligent about cleaning/charging it every 10K miles.

 

In addition to what Horatio aptly noted, cost is always an issue. If manufacturers are unwilling to include a couple bucks worth of plastic for rear fenderliners, they aren't about to spend extra for air filtration systems that will not be of value with the rest of the standard equipment.

As a performance engine builder and racer, I can say that most people would like to find (and believe in) a simple, singular, "magic bullet" that is cheap and easy to install, one which would make noticeable, if not gigantic, performance gains. There are always those willing to take advantage of this "something for (almost) nothing" mentality.

The hard, cruel facts are that if it were that simple, everyone would be doing it. It is NOT easy, cheap, nor simple to make noticeably more power from most of today's engines! Invariably, to see any gains, let alone significant ones, takes a number of coordinated modifications. Hence, if one significantly enhances flow out of the engine one may see some gain with enhanced intakes. Engines are simply airpumps and normally aspirated ones can be choked by bottlenecks anywhere in the system, within curtain parameters.

All else being equal--colder air allows for several things to happen that can enhance performance, e.g., more fuel and more timing without detonation and melted pistons.

All the best.

 

Well put Avanti. I've never owned a V8 before my Hemi and a smile just comes to my face everytime I give it that gas, both the stock rumble and pin to the seat power. I really can't see myself upgrading too much except for maybe a Magnaflow muffler for even more grumble and maybe a functioning Ram Air hood at some point. Having tried many of the "inexepensive" mods to my Jeep I used to have, I can attest that most of them did nothing appreciable in the power department. Here's what I did to my 4.0L I6 and what I felt about it. I say up front that nothing was measured/dyno'd etc, it's all how I perceived the changes. Sure, everything had to have done something but nothing noticeable enough to say "wow" what a difference:

1) Replaced the factory air box with a Rusty's air tube/K&N conical filter - Nothing I could notice over any RPM, yeah it looked neat under the hood but it did whistle a bit as noted by horatio and I saw nothing

2) Replaced the existing muffler and 2 1/4" piping from cat back to 2 1/2" mandrel bent piping with Flowmaster Delta 50 - Again, no noticeable gain to me, just an annoying rumble that irritated my wife to no end until I finally changed the muffler to an oversized Magnaflow. In hindsight for me, the I6 does not have a nice grumble with an aftermarket exhaust, it drones quite a bit, and not in a good way. Plus, it was all well and good to go from 2 1/4" to 2 1/2" in pipe size but the downpipe from the manifold to the cat was still 2 1/4" and had quite a pinch in the bend that pretty much wiped out the reasoning for the cat back system as far as power went.

3) Jacobs high end plug wires - I did this mostly to try and cut some EMI problems I was having with my aftermarket stereo system. THe plug wires I believe were 8.5 mm and allowed me to open the spark gap up a bit. Whatever they did do, didn't help my EMI problem at all! Blue wires looked cool though.

4) Jeepers and Creepers bored out throttle body - Now I will say, this actually had a noticeable change. It wiped out the mid RPM lag in the auto transmission and gave the Jeep more juice through the gears. I was very happy about this change although it whistled like mad at certain RPMs, I used to laugh it off as being my cheap turbo!!!

Other stuff that was advertised well but had no change for others that I knew included chipping, throttle body spacers, hi-flow cats, that Vornado thing. Again, the bored out throttle body was well worth it but it was $200 after core exchange. I heard that replacing the down pipe and adding a header helped out but with out a turbo charger, super charger, or stroker kit, forget it. You just weren't turning that I6 into a racing machine.

I assume the same holds true for the same mods for the Hemi or the 4.7V8.

 

Yeah, you're right. I'm one of those "poor, uninformed people" that bought the air-raid kit.....the only thing I noticed was it sounded better. That's about it.

Wish I would've found this forum sooner.

I also will pick up my new '05 HEMI Ram tomorrow and am NOT buying the air-raid. What I will be saving my pennies for is the ram air hood (functional) with the airbox directly into the intake. Sometime.

Learn a lot on this forum!

 

I've gotta agree with everything on here...also say it's pretty well thought out by everyone. I've only done the K&N filter. I've had them in other vehicles (have the same I6 as xj in both a Grand Cherokee and Wrangler currently) so I didn't expect any HP gains, but over the long term they do end up being cheaper. $40 for bascially forever vs. $15 every 15-20k or so. You do have to watch how you oil them. As you say, not enough and you pass too much crap. I did overoil mine once, but figured it out when I pulled the filter and saw the oil film in the bottom of the airbox before it did anything.

Not that I put alot of faith in the display computer, but it does show .5 to 1 mpg improvement with it for whatever that's worth. I've never had enought interest to actually check miles vs gallons to verify.

 

The problem with many of the intakes for our trucks is that they are not true cold air intakes. If the system is like the airraid intake, it is no more of a cold air intake than the stock system. It still gets a considerable amount of cold air from the engine bay. I think the best you can do is to use the stock box with a aftermarket performance filter, replace the flexible section to the TB with something smoother, and modify the stock box to get a true cold air source from in front of, or below the radiator.

IMO

 

Don't blame the aftermarket air intake for not giving you a MPG increase.

There has been lots of careful scientific testing of all kinds of air intakes
and the result is that they neither increase/decrease MPG on gasoline engines.

If less restrictive air inlet system improved MPG,
after the last 20 yrs of C.A.F.E.
(Corporate Average Fuel Economy)
government MPG standards,
you would now see massive & heavily insulated air intakes with 3 foot high by 6 foot wide
openings - even on the smallest 4 cyl compact.

Honda in a spirit of fierce pride, told its student engineers to do everything possible on the Insight
Hybrid to get the greatest possible MPG - they were in a competition with Audi CEO and
Porsche's grandson Ferdinand Piech who was having his engineers build the A3
aluminum body/3 cyl diesel as the world's highest MPG car.

Honda used every known trick in the gasoline engineering book to get over 70
MPG to beat Audi's fuel economy of 3 liters per 100 km on diesel. Notice that Honda was starting out about 20% behind because they were trying to make a gasoline engine powered vehicle beat a diesel power vehicle for 'world bragging rights.'

Go look at the air intake of a Honda Insight.
What do you see?

A properly designed air intake can give modest increases of torque and
horsepower at wide open throttle - but sometimes this comes at the cost of
increased noise or filters that get clogged with bugs and dirt faster.

But if you want a real answer you can trustabout an air intake design, then.......

Go down to Sears and buy one of the $30-70 multimeters with the temperature
probe. Sometimes they are on sale for $19

http://www.sears.com/sr/javasr/produ...26+Accessories



Then buy one of these $30 gauges that can measure low pressures and buy a
length of plastic tubing about 10 feet long to attach to it:

http://flw.com/olash2.htm#1490

Get the 30/30" pressure model.

If you don't want to spend this money you can also make a simple "U tube
manometer" with just a 20 foot length of clear plastic tubing and a yardstick:


Now drill small 1/16 th inch diameter holes in your stock air filter housing and air inlet tubing,
like at:

1. at the begining of the inlet tube
2. in front of the air filter element
3. behind the air filter element
4. near the throttle body connection

Put a fresh new air filter element in your stock filter box. Go out on a road
with little traffic and measure the temperature and pressures at your small
hole test points of the stock system when the engine is at wide open throttle
through the 2000 to 6000 rpm range.

If you find between two points that the temperature goes up, then the air is
picking up heat in that length between the two points. (i predict you won't
find much heat pickup)

If you find that the pressures go down between two points then there is
restriction in that section, like across the filter element ( i predict you
will only find a small restriction across the paper element of the filter)

Now try moving the air inlet to the stock filter box from its stock location
to other places - like the grille top or bottom. Look for a place where the
pressure is highest and the temperature is lowest. (I predict you will find
that the cavity behind the firewall and below the windshield will be best -
this is also where your air vents pick up air to ventilate the truck's cabin)

Now, if you are a bit more adventurous try the following experiment:

With all the stock air system in place, put the truck in 2nd gear and measure
with a stop watch how many seconds it takes to accelerate from 3000 rpm to
6000 rpm with wide open throttle. Do this test 3 times and average the
result.

Now if you are a little more daring and have found a clean road with little
dust in the air, think about doing the following 2 tests (it is optional but
informative)

Do the same test from 3000 to 6000 rpm, but with the paper air filter removed
from the box, and the box closed back up. This is the 'no filter but cool air
pickup' test.

Then do the same test, but with the air intake system removed and the throttle
body opening sucking the hot air from underneath the hood. This is the 'no
filter hot air pickup test.'

{The above tests sound dangerous without an air filter, but I can tell you
that many highway patrol officers removed the air filters on their cars in the
1970s. I have personally seen people pour uncooked rice down carburetors to
scour out carbon deposits. Lack of an air filter over long periods will cause
the bore walls and piston rings to wear out much quicker, but a quick test has
little effect unless you are unlucky enough to get a large chunk of something
down the throttle. If you are worried you can cover the throttle opening with
some eighth inch hole window screen material or mesh stocking}

Now go order the aftermarket air inlet systems of your choice and repeat the
pressure, temperature and 3000-6000 rpm acceleration tests in 2nd gear. Send
back the systems that don't do as well as the best for a refund of your money.

Report your results to Dodge truck forums.
You will be a hero to some,
the worst possible news to others selling junk.

Don't want to do all this testing?

Well, in a nutshell just remount your stock air box so that it will suck air
out of the cavity behind the firewall and below the windshield where your air
vents presently get their air. This spot will give you cooler air, higher
pressure air, and it will not pickup bugs/road grit as badly as an inlet near
the front grill.

Why didn't Dodge suck air from this spot in the first place?

Because with the interior cab air vent inlets there it allows A LOT of NOISE to go into the
truck's cabin.

As a matter of fact, most aftermarket air intakes JUST MAKE EXTRA NOISE. This
extra noise convinces most owners that they are making more horsepower - no
kidding.

If you read enough truck postings you come to the conclusion that many young truck owners are really after 'Excitement' not true vehicle performance you can time with a stopwatch. The loud mufflers, the loud stereos, the vibrations of hard shock absorbers, the unstable feeling while driving high lifted suspensions - it is really more about excitement than performance. Note many of these same vehicle owners are heavy players of video games.

Notice that I have not said to do dyno testing on your air intakes...I have
said do road tests.

Why?

Because you can't really test an aftermarket air intake system on a dyno where
the vehicle is not moving and an electric fan is blowing air at the radiator.
This makes it SO EASY TO CHEAT that you can make any air intake show a HP
increase on the dyno graph. Don't trust any dyno graph that claims to show an
aftermarket air intake horsepower gain. Realistic airflow around the vehicle
is critical to seeing whether it really works.

For examples about how one automotive enthusiast went about (imperfectly)
doing some home air filter element testing similar to that described above, go
to this link:
http://www.bobistheoilguy.com/airfilter/airtest2.htm

Also note that KN Filters lists how independent laboratories verify their air flow claims and their performance claims, but there is not a link to where an independent lab has verified any MPG improvement claim. That is because the engineers at KN Filters know that any MPG gain or loss that a customer reports is really just 'random variation.' But that does not keep KN from quotes such as 'Customers report 1-2 better MPG.' Note how that is 'literally true' but not 'scientifically valid.' Those are known as 'Weasel Words' in the advertising trade.

http://www.knfilters.com/testmethod.htm
http://www.knfilters.com/powertesting.htm

 

i've seen a bunch of SRT-10 style hoods floating around on hemi 1500's...does anybodyknow how much power those hoods add?