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CAI Evaluation

316K views 644 replies 235 participants last post by  guy65 
#1 · (Edited)
I see a lot of posts and questions about CAI's, so I thought I'd do a little checking and do some comparisons. Everything is based on my Ram, 2010 with the Hemi. I'm sure there are other CAI's out there but these are the more common ones.

BFI $329.00 not enclosed and not out in the cold air.
K&N $322.00 partially enclosed and not in the cold air.
Airaid $365.00 partially enclosed and uses some cold air from fender connection, would use full cold air if it was fully enclosed

AFE Stage 1 $336.00 fully enclosed and uses cold air from the fender connection.
Volant $405.00 fully enclosed but has hole in bottom for scoop attachment which would be easy to block. Uses outside air connection on fender.

For my money were I to buy a CAI, I'd go for the fully enclosed CAI's hands down. CAI means "Cold" Air Intake. In my mind any CAI that does not get its air from outside the engine compartment is not a true CAI.
 
#184 ·
Thanks! I'm glad the info was helpful for you!
 
#186 ·
Well if anyone is willing to donate a CAI I'll run the test :)
 
#187 ·
After reading this whote thread, I think the best answer for my 2011 is to leave the stock box, and keep the current drop in K&N I already have...

Boy, that hour of reading really saved me some money...
 
#188 ·
Hey nice job on the temp monitoring, did you try placing your prob inside the air box, wasn't sure when I read your comments, or perhaps I just missed it, I was curious as to free underhood air temps vs. Those from inside a warmed up air box?.. Thanks for your tests.... I suspect that as long as the intake air flows thru hot ducts, boxes, tubes, and into a hot throttle body, there really would not be alot of difference inside the combustion chamber.... We would have to flow the air through an iced box or tube and directly into the combustion chamber I suspect to truly gain much in a temp advantage... I think the real advantage to a CAI is a less restrictive air flow path and less restrictive filter... But hey what do I Know? Just some 50 years of Hot Rodding and drag racing under my belt... May have picked something up along the way, but this is just one old mans opinion, I welcome others
 
#191 ·
Hey nice job on the temp monitoring, did you try placing your prob inside the air box, wasn't sure when I read your comments, or perhaps I just missed it, I was curious as to free underhood air temps vs. Those from inside a warmed up air box?.. Thanks for your tests.... I suspect that as long as the intake air flows thru hot ducts, boxes, tubes, and into a hot throttle body, there really would not be alot of difference inside the combustion chamber.... We would have to flow the air through an iced box or tube and directly into the combustion chamber I suspect to truly gain much in a temp advantage... I think the real advantage to a CAI is a less restrictive air flow path and less restrictive filter... But hey what do I Know? Just some 50 years of Hot Rodding and drag racing under my belt... May have picked something up along the way, but this is just one old mans opinion, I welcome others
Yes the first test the thermocouple was under the air filter placed right in the middle of the air flow in from the fender. I hope that answers your question :)
 
#190 ·
The Airaid system seems to me much like the AFE system, with the exception of you being charged another $100 bucks or so for a strangely shaped tube and your paying for another air box bottom... AFE system uses the bottom half of the factory air box, instead of having to buy a new one for no real reason that I can see... But it's your money and you have to be happy with whatever you buy... I'd check each manufactures claims also for most HP & Torque... I hope you and your Ram are happy with whatever you choose
 
#192 ·
When I started this thread way back when, I had intended to generate some discussion on CAI's. I never expected the amount of discussion that has occurred. I must say I am pleased that those interested in buying or just the subject have taken the time to offer their insights as well as some pretty good test data.

The major flaw I see to all the CAI's whether stock or aftermarket is multi-fold:

1. The coldest air is going to be the air coming over the top of the hood but the only way to take advantage of that is buy a new hood and associated CAI.

2. Regardless of CAI, they are ALL a box and that means "turbulent" air rather than smooth air.

3. Filter restrictions are a common problem regardless of brand of CAI or filter. Some flow better than others, but are they actually worth the money? Unfortunately as opposed to drag racing vehicles, we need a filter to keep crap out of our TB's and engines.

4. I'm kind of old school on things. What that means, when I look to increase performance in one manner or another, I usually do it under the hood. When I want to change the sound, I do it with the exhaust. What I'm getting at is I see a lot of people talking about the sound the CAI makes. That's fine but it seems to me if you're going to spend $300 to get better sound, you'd be happier with the sound if you spent it on exhaust. That's where the real V8 sound comes from.

For my money, I've chosen the option of spending it on things that make RB look better/unique and in one case much more functional for me. If a CAI truly was going to give me significant mpg benefits, I'd do it in a heart beat. But so far I haven't found one that can prove its benefits. To me increasing average mpg by 1 or 2 mpg is not worth the expense. Justification for me means 5 or more mpg.

Just more of my $.02 worth here. :D
 
#193 ·
Iv been hearing that only fully closed cai is considered a "cold air' intake....but on my 06 I have a fender tube that leads to my box, and I think if I get a k&n the fender tube will fit inside the heat shield next the filter. Wouldn't that make it the better choice for me, that way it gets the cold outside air plus the less restrictive box right?? Any thoughts??
 
#194 ·
Here's the deal, what your seeking from any CAI is two fold,
1. Greater unrestricted air flow
2. The intake of cooler air

Now any system or combination of parts that improve on items 1, 2, or both should offer some overall improvment..
The factory system is always a compromise to many factors, performance, cost, multi vehicle use, sound, emissions, fitment, materials, & usability under a wide range of conditions, like weather & temp swings....
When you buy any system you are able to narrow down those perameters to one that more specifically meet your needs and wants, and ignore the others...
So any products you choose should, reduce the restrictions to the incoming air flow, by smoothing out the airs path, allow more air to enter and flow, larger components and freeer flowing air filter, and if it can also allow an intake of cooler air somehow, that's a good thing... Where you get the air from is up to you, you can run large tubes anywhere to pick up outside air, or to obtain a Ram Air/ or forced air induction effect from the vehicles forward motion, if you wish... Everything has it's positives and it's draw backs, so just remember, If one thing did everything the best, there would only be one type if system being used by everybody... This is why there are so many systems out there and so many opinions as to what may work best
 
#195 ·
Here's the deal, what your seeking from any CAI is two fold,
1. Greater unrestricted air flow
2. The intake of cooler air

Now any system or combination of parts that improve on items 1, 2, or both should offer some overall improvment..
The factory system is always a compromise to many factors, performance, cost, multi vehicle use, sound, emissions, fitment, materials, & usability under a wide range of conditions, like weather & temp swings....
When you buy any system you are able to narrow down those perameters to one that more specifically meet your needs and wants, and ignore the others...
So any products you choose should, reduce the restrictions to the incoming air flow, by smoothing out the airs path, allow more air to enter and flow, larger components and freeer flowing air filter, and if it can also allow an intake of cooler air somehow, that's a good thing... Where you get the air from is up to you, you can run large tubes anywhere to pick up outside air, or to obtain a Ram Air/ or forced air induction effect from the vehicles forward motion, if you wish... Everything has it's positives and it's draw backs, so just remember, If one thing did everything the best, there would only be one type if system being used by everybody... This is why there are so many systems out there and so many opinions as to what may work best
nicely put theweavman!!!
 
#199 ·
Question....

From what I'm gathering from this thread, other forums and people I talk to, the stock air box on my 2011 HEMI is excellent and there's no need to change it. However, the ribbed tube is definitely an issue. My question is, do they make an aftermarket "smooth" replacement tube? If not, would a throttle body spacer be a good way to re-allign the air flow out if the ribbed tube and into the engine???
 
#201 ·
From what I'm gathering from this thread, other forums and people I talk to, the stock air box on my 2011 HEMI is excellent and there's no need to change it. However, the ribbed tube is definitely an issue. My question is, do they make an aftermarket "smooth" replacement tube? If not, would a throttle body spacer be a good way to re-allign the air flow out if the ribbed tube and into the engine???
If you find an after-market tube, let us ALL know. :smileup:

As for the spacer, do a search on the forum and you'll find a large amount of people saying don't waster your money.
 
#203 ·
granted, colder air is always better and it was cool to see the temp comparisons... what i wish we could see at the same time is a measurement of how much air volume can move through the cai. Dropin doesn't flow enough for my truck...
 
#204 ·
Keep in mind that no matter where the air originates from, it is routed thru tubes which are inside your engine compartment and connected to your hot engine mounted throttle body..these plastic or metal air ducts pick up and hold heat from under the hood and heat the air as it makes contact and moves thru the ducts.....the very slight air temp differences between closed and open is so slight that I doubt it makes almost any difference at all, the biggest difference comes from having larger, smoother & straighter air ducts, plus a larger and less restrictive filter element, a check of the different manufactures rated HP and torque improvment claims might be a good place to start your evaluations...at least it offers some type of rated comparisons, beside price....none of them are going to turn a heavy 4X4 or 2X2 truck into an Indy Car...however, I know we all want as much bang for our buck as possible...and most of these systems are pretty comparible....If anyone brand was clearly superior in all respects, everyone would copy that design, and we would all be running the same system
 
#205 · (Edited)
The stock intake on a 4G Hemi is already a CAI, but has three weak points (IMHO):

The filter element is restrictive in size and construction.
The intake tube is ribbed, but not for her pleasure.
The fender opening is restrictive and not conducive to maximum airflow.

For those who have not looked at the fender opening, the headlight bucket/bracket and frame obstruct most of the opening ...
The restrictive fender duct is (IMHO) the lowest common denominator to ALL current CAI's, and the main flaw/obstacle most manufacturers have neglected to address.
...although the Volant does have an optional lower port on their box that would benefit from this cheap little bumper Ram mod.


Here's the view from the engine bay after removing the stock box:



view from the front on a friends Ram with headlight removed at the track


Close up




The "limited" path the air has to take when the headlight is installed




My Solution for better flowing, cooler intake air that anyone can DIY:

1. Lose the Engine cover ! (it's a Heat Trap!)
that does nothing but cook your intake runners! (Free!)

2. Install a Jet 180º T-Stat ($30) simple 10 minute swap
...cool your engine by 15º and your engine bay temps and intake air temps will be lower too.

3. Billet Technology Catch Can ($130) another 10 minute mod anyone can do
not really a CAI mod in itself, but a supporting mod to reduce Hot Oil saturated vapor directed to Your Intake from the PCV

4. Get the Biggest Filter element available! No such thing as too Big!
I went with Airaid after trying the stock box K&N drop in and found it wasn't enough.

5. Larger, Smooth surface plastic intake Tube!
for me, Airaid's Triple Lobe tube fit the bill once again.

6. Fastman's Modified 85mm Throttle Body ($212 shipped)
the polished Taper Bore and Half Shaft mod free up more flow at a higher velocity.

7. Ram Air! I redirected my air source to take in air from the lower "Front" of my Sport bumper after removing the fake plastic grill.
adjustable Flex Tube ...actually designed for draining water away from your house ($6) Lowes Hardware.

Of course having the Tuning and Exhaust supporting mods helps too
(Magnaflow CatBack and Y-Pipe, and my JBA Headers are on the way)

Pic's (of course)


my HUGE Airaid Filter element




Smooth Triple Lobe intake tube (old pic before engine cover was removed and tossed)


The Rubber edging seals the box to the underside of the hood, but it's not 100%.
So I picked up some self adhesive foam/rubber pipe insulation from Lowes ($5)
and ran it right over top the rubber seal and along the fender side edge too, pic's coming soon.



Billet Tech Catch Can


After just one week after install and a single evening at the track, about 8-9 quarter mile passes...




Stock TB vs FastMan Throttle Body (right) taper bore 85mm and half shaft removed for a smoother higher flow




Removed lower fake grill. I think it looks better without it anyway
it's ugly, non-functional, faded plastic and doesn't match my Black Honeycomb upper grill anyway.
I cant prove it, but I'll bet it helps engine bay air circulation/ventilation as well. No tools required, 5 minutes



Lowes Hardware 3.5" Flex Tube (I bought two and a coupler, but because they can extend and bend from 9" up to 21" only one was required)


intake air is now "Rammed" in and up toward the stock fender port from the FRONT where air pressure is highest (at speed) instead of the motor having to suck air from below.




View from below, lower left is the input side, lower right is the fog light housing, up the fender is the blue bungee cord holding the top of the tube in place.
(There's a second bungee holding the lower front of the tube near the bumper)



Testing has been limited to street only so far and I'm melting my poor Terra Grapplers! I can tell by my butt dyno it's working well.
Track testing to follow, and I still have to get a base line Dyno run (slated for August 12th) before my Edge Torque Converter and JBA Headers get installed then my custom CMR Dyno Tuning session.
 
#215 ·
Lowes Hardware 3.5" Flex Tube (I bought two and a coupler, but because they can extend and bend from 9" up to 21" only one was required)


intake air is now "Rammed" in and up toward the stock fender port from the FRONT where air pressure is highest (at speed) instead of the motor having to suck air from below.




View from below, lower left is the input side, lower right is the fog light housing, up the fender is the blue bungee cord holding the top of the tube in place.
(There's a second bungee holding the lower front of the tube near the bumper)



Testing has been limited to street only so far and I'm melting my poor Terra Grapplers! I can tell by my butt dyno it's working well.
Track testing to follow, and I still have to get a base line Dyno run (slated for August 12th) before my Edge Torque Converter and JBA Headers get installed then my custom CMR Dyno Tuning session.
Great idea with the tubes bud, but will all the ribs you are loosing a lot of air flow. If I was you, I would use them as a template and take them to your local fabricator and have him make you a set of Alum tubes with the bend you need. You will notice the difference. ;)
 
#208 · (Edited)
The top of the flex tube is heading toward the stock fender opening, the same opening all 4G CAI's use...
and stops just below the frame (green oval below), I didn't see any benefit to crushing it to go any further.

The "Difference" is instead of relying on the TB's ability to "suck" air up from the mostly enclosed lower fender area behind the bumper's dead air space
It's now Front "Forced" live air that's Rammed up there from forward momentum :smiley_thumbs_up:



I still might try and fab a rectangular shaped funnel to match the bumper opening,
then mod the plastic lower grill surround and make it a functional Honeycomb grill to match the upper one.



Similar to what MGH did in front for his inter-cooler on his twin turbo setup:

 
#213 · (Edited)
I might try the tube with a used Volant I am waiting for! :)
The Volant has lower port built into their sealed box already just begging for this mod
and I hear production of an optional lower air scoop will be out in November for the 4G Ram's.

They do it for several other makes/models already http://www.volant.com/scoops.asp
this is what the Chevy Silverado HD unit looks like:

 
#214 · (Edited)
Right after I shot this pic I realized just how nasty the dirt and bugs collecting in the fins was ,
I dont normally see my filter from this angle so I thought it still looked okay from the front...Ooops!

Guess I'm due for my first cleaning/re-charge after almost a year :158:







Soaked it with degreaser and let it sit for 10 minutes


Then rinsed from the inside out with a light low pressure shower nozzle on the garden hose and let it dry for 4 hours next to a fan.
Then a light spray oil and let it wick in for 20 minutes...check for white spots and give it another light dusting of oil and let it dry overnight before re-installing the morning.
Bet I'll be even Faster getting to work tomorrow now! :D

Clean and Dry waiting for some fresh Red K&N Oil.
I use the K&N recharge kit because it was only $12 locally vs $20+ for the Airaid recharge kit.


This shot gives a good idea of the filter size compared to a coke can...with some fresh Red Oil!
 
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