Scientific Intake Selection and Review

[6.7Bison]

Thought I would share my intake selection and review while trying to approach it scientifically.

A little background.
I own a 2011 F-250 crew cab short bed with the 6.7L powerstroke with approximately 100,000 miles on it and is currently all stock. The truck was purchased used with the main purpose of towing and hauling with some commuting. I keep track of fuel mileage pretty religiously and hand calculate whenever I can get back to back fill ups (the wife is not as good about remembering this). I am getting approximately 18 mpg on my rolling hilled highway commute in the summer running 60-65 mph. In the winter I have seen this number hover between 17 mpg and 15 mpg all depending on how good I am at remembering to plug in the block heater the night before. I have seen as much as 20 mpg on longer flatter interstate runs at 70-75 mph during the summer. As I have not completed a full tank just towing I don’t have perfect numbers and I bounce between towing our steel gooseneck trailer and our bumper pull high deck flatbed trailer. Towing in the summer I seem to be around 15 mpg. Towing in the winter I have seen as low as 12 mpg.

Like most of us here I like to get more out of my truck and know that there are always compromises made by the manufacturer when mass producing a vehicle. That being said I have a long list of parts that I wouldn’t mind swapping, upgrading, adding, or changing. The struggle is justifying it to myself and my wife. My first opportunity reared its head when I was doing a check of components as we gear up for a long trip to Texas to see family and haul back a small tractor. The filter minder was sucked down to the last line before the red on the intake box. A quick disassembly and a black dirty filter confirmed that the filter would need replaced soon. I know the stock intake is a true cold air intake and is capable of handling up to 500 HP. But I can’t help my problem solving nature. Looking at it I thought surely I could do better than a stock replacement filter.

 

[6.7Bison]

My selection process and outcome.
My selection criteria for an intake was that it had a filter efficiency of stock or better, had a cleanable dry filter, someone somewhere made a dust cover for it, and improved fuel mileage. Throttle response improvements, room to grow for future modifications, and improved low end power are greatly appreciated with peak power being icing on the cake. Obviously I didn’t want to put a filter on the truck that didn’t prevent dirt, dust, and debris from entering the engine at least as good as what came from the factory. I learned a few things having had an oiled K&N intake before. The oiling process was a pain, it was easy to over or under oil, and unless I was religious about cleaning and re-oiling it often, dust found its way into the intake. Being able to clean the filter and reuse it would help to justify the cost to me and my wife. The pre filter dust covers I have seen used in other applications in my area appear to do really well. They are an additional bug, dust, and moisture barrier to the filter extending its life and making it easier to clean. If an intake is doing its job of easily breathing in fresh air, it should improve fuel economy. This also makes it easier to justify the upgrade. Coming from a non drive by wire naturally aspirated V8 truck, a drive by wire turbo V8 diesel is lacking in throttle response though not unbearable. This is the first performance mod on a longer list so I don’t want to have to revisit it later because it becomes the choke point. Low end power coupled with improved throttle response help the towing confidence of the truck. And who doesn’t like to brag about peak numbers?

The three major types of intake upgrades I looked at were drop in filter, air box replacement only, and complete intakes. While just the drop in filter hit much of what I was looking for they were smaller improvements than I might have liked. The air box replacement only styles claimed decent numbers and some people love them. But I kept staring at the OEM intake tube and saw the compromises made for fitment, sound deadening, molding, and cost. For the small price difference of the airbox replacement style and the complete intake, I decided it was worth the extra money for the complete intake.

The two main styles for these brands were open or enclosed filter. Common sense would dictate that the enclosed style would be more effective as it blocks access to the warm air of the engine bay and instead focuses on funnelling cool fresh air from outside of the vehicle. However, when researching the different specific intakes the open filter design seemed to have more consistent reports of more power (shown in back to back dyno sessions as solo modification and with other more extensive modifications), reported mpg gains (approximately 1-2 mpg where the enclosed style reports were anywhere from a loss of 1 mpg to a gain of 4 mpg), and a larger following (so much so S&B made one). This had me scratching my head. I acknowledge the majority can be wrong so I can’t put much weight behind the fact that a lot of people are buying them. But the reviews seemed to be genuine that most everyone enjoyed the intake, some even having switched from an aftermarket enclosed style to the open style. The consistency of the uptick in mpg along with the evidence in back to back dynos made me think there has to be more to the story which lead me to my current hypothesis for the 2011-2016 Powerstrokes.

Point 1 of my hypothesis: At most driving speeds, engine bay temperatures anywhere near the intake are at or much closer to ambient temperature than we are led to believe.

Point 2 of my hypothesis: Enclosed style air intakes are more restricted due to being enclosed. Some brands work very hard at keeping the enclosure large and unobstructive to the filter. But I believe the very nature of further boxing in the filter creates restrictions.

Point 3 of my hypothesis: Enclosed style air intakes still rely on air routings provided by the OEM through the front grill, headlight, bumper, fender, etc. to draw in fresh air. These openings may not be sufficiently large enough or are restrictive enough that they have a larger impact than we are led to believe. Aftermarket intake manufacturers may be aware of this or may not but I doubt they would modify this portion of the air routing unless it was as easy as an additional scoop or horn on the intake.

As I work through my intake upgrade I plan to test this hypothesis at least to the satisfaction of my needs. But first I still needed to select an intake. From what I learned during my research, the open style appears to be the better design. If need be I can also create my own enclosure to shield the intake from high engine bay temperature. This can be done easier than starting with an enclosed filter without the enclosure. This left me with three true options and 1 partial option: No Limit Stage 1 and 2, S&B Open Air, and AFE stage 2.

Since I plan on leaving my emissions systems intact and do not plan on being able to tune the truck for some time I eliminated the Stage 2 No Limit intake. Looking over the partial open AFE intake I decided against it as it still had an enclosure to work around and I was unsure of the necessity of the number of jogs in the tube. After much deliberation between the Stage 1 No Limit and the relatively new S&B Open Air, I ended up going with the S&B. The massive dry cleanable filter has a tested 99.90% efficiency. The massive smooth intake tube is made of plastic which will help to insulate the incoming air from heat (should it prove to be an issue) but still tuned for the stock calibration of the MAF with an insert. It sounds like the insert may be removable should you be able to update calibrations similar to the Stage 2 No Limit for even more airflow but it’s too new to tell. I will let someone else tell me whether that is possible and do more research later to see if it’s a good idea. The intake has a supporting bracket near the filter to help support the intake and keep it properly positioned for a simple install with little tweaking. Since there isn’t much info out there on this intake I thought I would try to document and share what I find.

I am in no way bashing any of the other systems as they appear to be quality systems. I am just explaining my reasons for my final selection and let me tell you it was not quick or easy. I also want to note that I’m not receiving any compensation, kick back, freebies, or discount from anyone for this write up. I’m just sharing my experience and doing my best to be unbiased and informative in the process.

 

[6.7Bison]

Outcomes of my baseline runs.
For some future comparisons to test my hypothesis and make sure the intake does what I want it to, I took a couple baseline runs with the stock intake on some temperatures. The numbers seemed to be in line with what I have seen before as well.

After 5 minutes of initial start up and idle. Truck was plugged in the entire night beforehand inside a three sided shed:
Ambient temperature was 9F. Intake air temperature was 27F.
Granted it was very cold so the temperature difference is probably exacerbated but that's still a difference of 18F with what is regarded as a true cold air intake.
After getting warmed up during the commute at 60-65mph (engine temperature needle was directly in the middle):
Ambient temperature was 3F. Intake air temperature was 3F. CAC temperature (directly after the intercooler) was 62F on the flats and 68F climbing the hills. EGT from the factory stock location 420F on the flats and 530F climbing the hills.

After 5 minutes of initial start up and idle. Truck was parked in an open parking lot:
Ambient temperature was 46F. Intake air temperature was 41F.
My best guess here is the direct sunlight heated the ambient sensor to higher than the actual air temperature as is seen below.
After getting warmed up during the commute at 60-65mph (engine temperature needle was directly in the middle):
Ambient temperature was 41F. Intake air temperature was 41F. CAC temperature (directly after the intercooler) was 77F on the flats and 82F climbing the hills. EGT from the factory stock location 460F on the flats and 600F climbing the hills.

Again there is good evidence that supports the stock system being a true cold air system. I will do another couple runs after the installation of my system to compare both at an idle and on my commute though it is starting to warm up here. If temperatures creep up too much I will look into blocking the warm air from the engine bay from entering the intake.

I would have recorded MAF numbers but there are enough ambient variables in play let alone the ones the engine adds I don’t have a high level of confidence in runs that aren't back to back. The best I can think of is a run before and after the installation in park at a couple different rpms directly after a cold start. This way I can check the flow increase claims made by S&B in real world situations. Depending on the numbers, what I find during installation, and what I find out with temperatures I might try opening up some air paths.

I don’t have access to a dyno for before and after for more official power and torque curves. Best I can do is the butt dyno and driving impressions. I will also keep track of fuel mileage with the new system. It may take a while to collect the data as this is not the primary vehicle so please be patient with me.

 

[6.7Bison]

Ordering and unboxing.
I ordered the intake and prefilter directly off of the S&B website as they gave me the best deal after tax and shipping. I got the economy shipping and the packages arrived in 3 short days. When I got the packages I opened them up to inspect that everything appeared to be there and there was no damage in shipping. Everything made the trip ok and everything appeared to be included.The first thing to catch my attention was just how massive the filter and tube are. Odd as it sounds I would equate it to about the size of a bathroom trash can. The media of the filter almost has a corduroy look to it which I found to be interesting. Since they didn’t have a clear photo of what the insert was I was curious how that would look. It's a very smooth transitioning rectangular funnel that fits right behind where the filter goes. It looks like it would be easy to remove or replace if I ever get to the point of tuning the truck and working with the tuner to determine if it would be worth it for additional airflow. The tube is thick plastic and sturdy with the inside being glass smooth. It is absolutely massive and looks to have smooth transitions though there is one indent that I was not expecting underneath near the mount. The insert flows air over this so it isn’t much of a concern currently. The ⅛” thick bracket also looks sturdy and has a powder coat finish. The miscellaneous other components all look to be made with quality in mind. I also got a couple S&B stickers that I am unsure of what to do with. I plan on having it installed by the end of the weekend.

 

[6.7Bison]

Rest of the pictures from unboxing.

 

[HeavyAssault]

Well I run a No Limit Stage 2 with a prewrap. It's an open element filter system, that doesn't show anything different than your numbers as above. The biggest "argument" people attempt is that it sucks in the hot air from around the motor.....Not really.



Yes, at idle standing still it will raise the intake temps. After moving for 2 minutes those temps drop away to ambient temps.

Point 1 of my hypothesis: At most driving speeds, engine bay temperatures anywhere near the intake are at or much closer to ambient temperature than we are led to believe.

I already have evidence this is true. So mark that one off the list.

 

[Connor M]

Can read this now but it looks like you’re doing an awesome writeup, I want to read this later

 

[erbear28]

Ford did a good job with underhood airflow so it really comes down to personal preference. Open or closed is fine

 

[Connor M]

Ford did a good job with underhood airflow so it really comes down to personal preference. Open or closed is fine

Hey buddy, glad to see another OGTT guy here.

 

[Connor M]

Common sense would dictate that the enclosed style would be more effective as it blocks access to the warm air of the engine bay and instead focuses on funnelling cool fresh air from outside of the vehicle. However, when researching the different specific intakes the open filter design seemed to have more consistent reports of more power

You have to remember in a turbo diesel, the compression from the turbo heats the air up.
A lot.
Then the air goes through the intercooler, which should bring it down to just over the outside air temp. The difference between the fenderwell and engine bay temperatures is likely negligible in the end and the flow rates of the open element overcomes any air temp differences.

 

[erbear28]

Hey buddy, glad to see another OGTT guy here.

I’m everywhere lol just not that active on here

 

[6.7Bison]

I already have evidence this is true. So mark that one off the list.

Ford did a good job with underhood airflow so it really comes down to personal preference. Open or closed is fine

Glad to hear some of you can back up my hypothesis! This gives me hope I won't have to do any further modifications to get more cool air to the intake. For my own purposes and to keep this write up and review complete I will still gather data after the install and post my findings.

Can read this now but it looks like you’re doing an awesome writeup, I want to read this later

Thanks! Sounds like I'm on the right track to being informative and unbiased.

You have to remember in a turbo diesel, the compression from the turbo heats the air up.
A lot.
Then the air goes through the intercooler, which should bring it down to just over the outside air temp. The difference between the fenderwell and engine bay temperatures is likely negligible in the end and the flow rates of the open element overcomes any air temp differences.

You are correct the turbo heats up the air a ton and the intercooler is in place to help bring the temps back down. I've done some thermodynamics math with a lot of assumed values and raising the intake temp from 70F to 75F only decreases the mass airflow by approximately 0.75 lb/min. Not a whole lot and I would probably never notice real world. You are probably correct that just the larger element would make up this difference... But if I can have more air AND colder air AND a lower pressure drop from a new intake setup... :demon:
I like performance and efficiency but don't like compromise.

 

[erbear28]

Glad to hear some of you can back up my hypothesis! This gives me hope I won't have to do any further modifications to get more cool air to the intake. For my own purposes and to keep this write up and review complete I will still gather data after the install and post my findings.





Thanks! Sounds like I'm on the right track to being informative and unbiased.





You are correct the turbo heats up the air a ton and the intercooler is in place to help bring the temps back down. I've done some thermodynamics math with a lot of assumed values and raising the intake temp from 70F to 75F only decreases the mass airflow by approximately 0.75 lb/min. Not a whole lot and I would probably never notice real world. You are probably correct that just the larger element would make up this difference... But if I can have more air AND colder air AND a lower pressure drop from a new intake setup... :demon:

I like performance and efficiency but don't like compromise.

Steve Carter who runs absolute performance has done some similar testing

“For example, the Absolute Performance intake shows a 2-7* delta of intake temp vs ambient air temp. Similar to the stock 3-5* delta. Both intake systems drawing air from the factory location. Those delta numbers alone dismantle the "hot air intake" comments but let's take it one step further...

Underhood air temp issues in these trucks at 40,50,60,70+mph are almost non existent. The engineers at ford have mastered under hood airflow beings that the front stack in the core sees a massive amount of air across its surface area, moving into the engine bay and down out under the truck. Keeping a large portion of the area near the major heat emitting components covered with cooler ambient air which eliminates the hot air pockets most have come to expect to be under the hood. Speaking of heat emitting components, thankfully the 6.7 motor design has all the exhaust components in the valley of the engine, and the intake on the outboard side. Even further eliminating heat soak issues or potential. Throw in the fact that the air filter on the Absolute intake is surrounded by the battery box, front core and fender, or on the 2017+ trucks - surrounded by the egr cooler and battery tray, you really just don't have the "hot air intake" effect some people uneducatedly claim to exist.

Now let's get down to why even if it was a "hot air intake" it wouldn't matter....

This particular motor is setup with a inline air to water intercooler which is tasked with cooling the air charge to the motor post turbo. Now most people don't know or at least aren't thinking of the turbo as a air compressor and the physics of compressing particles like oxygen at a high rate of speed, what occurs. The biggest being heat. The 6.7 turbocharger absolutely can and will create charge air temps (post air intake system) that are 5x higher than ambient air temps. Meaning on a 75* day, I have seen Air Intake temps as high as 400* at WOT. Cruising speeds the turbo usually creates 2-3x higher air charge temps than ambient. The air intake system albeit stock or aftermarket only affects that number by single digits in my testing. Which doesn't really mean much, and wouldn't mean much even if the temp was 10-15-20* higher because that wonderful little inline intercooler is in place to bring those temps down and make them optimal again.

So what's the point of an Absolute Performance Air Intake system? VOLUME. Cramming as much air into the turbocharger as humanly possible. Obviously the more available air to the turbo there is, the more efficient that turbo will be in the essence there isn't a restriction on the inlet side making the charger work harder to do its intended job. How does this relate to you in terms of performance? Horsepower and more notably, throttle response. Crisp and clean off the line, every time

So... take it from a guy that's spent the months testing these systems and products with data logging equipment in a variety of setups, scenarios and locations - there is no such thing as a "hot air intake" on a 6.7 Powerstroke”

 

[HeavyAssault]

@erbear28: Did you see 400* F post-CAC on WOT runs??? Or was that pre-CAC temps?



I've never seen higher than 20-25* F over ambient post-CAC for any driving condition.

On a good day cruising around the post-CAC numbers could be as low as 15*F over ambient. Don't expect that all the time.

But if I can have more air AND colder air AND a lower pressure drop from a new intake setup..

Which is only relative to the performance of the CAC. As long as it's doing it's job you will never see anything below ambient air going into the motor.



Keeping the conversation to just the intake system up to the compressor housing, when driving around my No Limit Stage 2 will pull temps at ambient or 2*F less than ambient.

 

[6.7Bison]

Great discussion here guys!

Steve Carter who runs absolute performance has done some similar testing

So... take it from a guy that's spent the months testing these systems and products with data logging equipment in a variety of setups, scenarios and locations - there is no such thing as a "hot air intake" on a 6.7 Powerstroke”

Keeping the conversation to just the intake system up to the compressor housing, when driving around my No Limit Stage 2 will pull temps at ambient or 2*F less than ambient.

I hadn't seen his testing but again good to know my hypothesis of ambient like underhood temperatures seems to be confirmed by others. I'm just going through the paces to make sure my upgrade is indeed an upgrade in all the areas I want it to be.

This particular motor is setup with a inline air to water intercooler which is tasked with cooling the air charge to the motor post turbo. Now most people don't know or at least aren't thinking of the turbo as a air compressor and the physics of compressing particles like oxygen at a high rate of speed, what occurs. The biggest being heat. The 6.7 turbocharger absolutely can and will create charge air temps (post air intake system) that are 5x higher than ambient air temps. Meaning on a 75* day, I have seen Air Intake temps as high as 400* at WOT. Cruising speeds the turbo usually creates 2-3x higher air charge temps than ambient. The air intake system albeit stock or aftermarket only affects that number by single digits in my testing. Which doesn't really mean much, and wouldn't mean much even if the temp was 10-15-20* higher because that wonderful little inline intercooler is in place to bring those temps down and make them optimal again.

I agree with you here and can dive into the math to support it. My only counter point is that the intercooler isn't perfect. While it takes out a lot of heat from the air it will never take all of it out. In fact the higher the temperature in the higher the temperature out. The turbo has the same effect. So in theory in order to have the highest density possible for any setup you want to keep out as much additional heat as possible from start to finish. In the real world the lost density of a 20 degree difference in ambient to intake temperature may not be a whole lot different at the cylinder and may not even be noticeable to the average person. Especially if you increase volume and decrease pressure drop at the same time. But sometimes I live in my own world... :morons:

How does this relate to you in terms of performance? Horsepower and more notably, throttle response. Crisp and clean off the line, every time

That's what I'm looking for!

Which is only relative to the performance of the CAC. As long as it's doing it's job you will never see anything below ambient air going into the motor.

I've heard of a few tricks drag racers use to get manifold air temperature below ambient but they aren't exactly feasible for a daily driver...

Circling back to the main thread topic, I did get the intake installed yesterday. Just need to organize my thoughts, data, and pictures.

 

[HeavyAssault]

Not sure what you are trying to gain now with all this effort. If you are only concerned about airflow to the turbo compressor housing I might have a better understanding of your efforts here. Are you just doing all this to prove to yourself what you already know to be true??

 

[sootie]

Wow what a waste of time, effort and money

 

[6.7Bison]

I'm checking the manufacturers claims against what I can determine with real world data and sharing my findings. The open air intake from S&B is relatively new and there wasn't anything out there on it. Cant say I know anything about it except what the manufacturer claims.
For my purposes I am wanting to improve fuel economy, protect the engine from ingesting dirt and dust, and not have to buy another filter for as long as I have the truck. I would like more power, throttle response, and not hinder future modifications but that isn't necessarily a requirement. Can't say it's really all that much effort or time. It's been more effort and time sharing my findings here than any other part of this. As for money, the intake pays for itself being able to wash and reuse the filter alone.
If it is the consensus I am wasting my time and effort, and there is no interest in what I am doing, I can simply stop sharing my findings and experience.

 

[dsberman94]

NAPA 6637 filter with a washable filter sock has been proven to flow enough to make big power in 7.3s for years. And it’s like 50 bucks for the filter and the cover. I’d imagine there would be enough room in a 6.7 to put that filter in also.

 

[HeavyAssault]

For my purposes I am wanting to improve fuel economy, protect the engine from ingesting dirt and dust, and not have to buy another filter for as long as I have the truck. I would like more power, throttle response, and not hinder future modifications but that isn't necessarily a requirement.

You should have bought a No Limit filter and system. I've run the same one for over 100k.


More "power" from an intake alone isn't going to happen.


By all means, post your experiences and findings. If you discover it works for you then so be it. If you discover it was a waste of money then so be it. You will either discover what many already know, or show a different result.


Just remember you are only changing a small portion of the airflow path.