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Old 10-31-2012, 03:31 PM   #1
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Who's In The Cold Air Intake Club and What Do Ya Got?

I saw the De-Snork club and wondered how many have REALLY UNLOCKED the POWER of their car WITH A COLD AIR INTAKE and what type of system do you have?

I'll start. I am a new member of the Cold Air Intake Club. My CAI is still being tested for optimum efficiency. It is comprised of a HUGE 6" X 11" conical air filter, with silicone hoses and stock MAF piece, with a screen for now. The intake is 4" at the start and ends up at 3" for the MAF and Throttle Body, they have BOTH been relocated CLOSER to Throttle Body.

I must say the Butt Dyno is on overload! This thing is scary fast now. I am almost not sure why there are not kits out there that have done this.

From doing research on this…some of our members have pretty COOL AIR INTAKES, pun intended….so let's hear about yours! Anyone modify theirs yet? I will show you mine soon, but let's see yours now!
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Old 10-31-2012, 03:56 PM   #2
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The Snork...
I was surprised what it looked like until I removed it..

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Old 10-31-2012, 04:01 PM   #3
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When I had a 986 I just took off the holy water blessing cup at the end and replaced the trumpet horn. Many cars I have seen over the years had that same inlet, including a lot of air cleaner inlets, the 396 SS had it. If it's been used that long the design must be well established as the way to increase inlet volume. As for homeboy, I'm glad you made a mod you are happy with but it's a little hard to believe just that mod made it "scary fast".
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Old 10-31-2012, 04:28 PM   #4
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...sorry to burst the bubble, but all Boxsters are cold air intake, desnorkling allows for more air flow, but all of our cars are "cold air intake" designed.
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Old 11-01-2012, 06:53 AM   #5
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Hi All,
I understand opinions vary…de-snorking is a good first step, but, have you seen inside your airbox? It looks like an "old river" winding back and forth! It goes larger, smaller, larger, etc. the tube size is NOT consistent either! For those people who want their car stock…this thread is not for you!

I don't care IF it is stock or not, just that it runs better! It is natural for you to not believe me. But BEFORE YOU ARGUE, prove it to yourself….take out the air filter AND LOOK WHERE THE AIR GOES! It has to go a 'country mile' before it ever gets to your engine! Once it comes in COLD from the outside, the airbox does a 180 degree bend and BEFORE it goes through the air filter! 180 degrees!

Truly COLD AIR, air pooling, air turbulence and air volume are the most important. The Factory design is great for sound reduction and noise at the intake, not power! Ever see a race car with a long, crooked intake? Nope.

Also, by placing the MAF closer to the Throttle Body you achieve MORE ACCURATE readings of the ACTUAL AIRFLOW-DIRECTLY BEFORE it goes into the engine. This was not something I made up. Many people with a multitude of vehicles have tested this. I am determining the best placement as we speak.

@Ghost, I KNOW the claim is hard to believe. However, I DO KNOW it has woken up my car and I am just running with semi-cold air at this point. It could be me testing it harder and harder but the tach does get pegged a lot quicker! Check it out before you dismiss it, that's all I am saying.

Yes @Eric G, (love your instructables), but while it is 'theoretically' a cold air system….the plastic used "warms" the air up! Have you touched the intake tube after a hard run? Warm, not cold. Silicone is much better as it does not transmit as much 'thermal' or conductive heat. The more air resistance too, the more heat is generated.

Again, while the design of your air flow is to use cold air….the longer the straw, the more resistance. Common physics. For those doubters, before you spam me about this….check it firsthand! LOOK at your OWN AIRBOX!

Further, as you increase the volume of air (to a point-that point being the MAFs ability to adjust) you get more power. Period. I don't see how anyone can dispute that, and honestly if you do, to each their own…we can still be friends! I am only trying to provide information to folks who may want it.

I have spoken with several people who have made their own intake systems. There are a BUNCH out there and there are many options, each claiming to be better than stock (even a bad design would be)! The problem seems to be that they all use this 3" plastic hose portion from the MAF to the Throttle body, and it has a "lagoon" and an accordion in that piece too! Air needs to be directed gentlemen. Therein lies your answer.

If your stock system suits you, great!

If not, tell me about it as I have learned form everyone who has ever built one of these systems….that is what this thread is about! Learning!

And where is a good engineer when you need one? BUT I want to hear from people who have ACTUALLY INSTALLED A COLD AIR INTAKE…come on, I KNOW you are out there! Sound off!
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Old 11-01-2012, 07:46 AM   #6
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Homey, like my grandmother used to say "if you like it, I like it" no offense was intended. I did try numerous things with the 986, I think Mr Raby said in here that every dyno he did showed reduced performance with de snorkeling. The only mod I really felt from the driver's seat was headers & underpulley, that did give the car a nice little bump. Speaking only for myself, I will never mod my spyder, it's staying bone stock, it's plenty fast enough to go to jail with every trip.
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Old 11-01-2012, 12:54 PM   #7
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The claim that snorkeling is counterproductive is somewhat controversial...

Finally: Dyno charts of de-snorked 986S!!!

I can't find the link to the thread at the moment, but Jake even touts the desnorkling of a 2.5l boxster spec car.

Take caution before it's know-all end all.

~~~ It's also true that our car stock has a cold air intake- albeit a rather inefficient one. I did not believe it was that bad until I actually saw the maze with my own eyes. Don't except a massive jump rocket in horsepower, but you would indubitably free some horsepower up.

Last edited by Kenny Boxster; 11-02-2012 at 09:05 AM.
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Old 11-01-2012, 01:08 PM   #8
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I tried to google the theory of why the inlet is shaped that way, I didn't get far as I didn't know how to approach the subject too well. With the resume of the owner thread, someone on here must be able to explain whether that "trumpet" style inlet accelerates or shapes somehow the incoming air. I'd also like to know what the 987 intake is like as I haven't been in there to check the air filter yet.
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Old 11-01-2012, 01:38 PM   #9
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Homeboy,
Do you have any pictures to post ?
List of parts and where sourced?
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Old 11-01-2012, 02:01 PM   #10
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Quote:
Originally Posted by Ghostrider 310 View Post
Homey, like my grandmother used to say "if you like it, I like it" no offense was intended. I did try numerous things with the 986, I think Mr Raby said in here that every dyno he did showed reduced performance with de snorkeling. The only mod I really felt from the driver's seat was headers & underpulley, that did give the car a nice little bump. Speaking only for myself, I will never mod my spyder, it's staying bone stock, it's plenty fast enough to go to jail with every trip.
Hey Ghosty,

My Grandma, rest her soul, taught me a thing or two too. Such as, "Comparing apples to apples"….aren't you rowing a 7 speed now? Don't know what you have under there. Wouldn't want to change it IF it was mine, newer AND cost that much. Don't blame ya.

Move along boys and girls, we KNEW there would be Ghosts out at this time of year... he-he (got to work in a Halloween joke)

Seriously, Headers & a UD pulley are on the list but this is about Cold Air….need to hear from those that have, "Been there, done that….and achieved happy results."

Not that yours and Jake's "vote" doesn't count! I hear what your sayin' but there ARE people out there that HAVE DONE THIS SUCCESSFULLY!

I can post a rudimentary modification that I did…costs under $75 for a conical air filter and Silicone adapter. The rest of the parts come out of the factory airbox. I don't like to "trumpet" my results but….

Re-use the trumpet piece, it has been ground down to a numb! Just needed the screen and part of the housing-about an inch to fit the adapter. Then, re-using the MAF section* (which needs to be carefully extracted-didn't say you did not have to be careful-I just said it was inexpensive).

For sure it will straighten out the airflow. Does that mean more horses…I say, "Yes!" Butt dyno results say YES! But, let's see how much!

Anyone got a REAL DYNO in Dallas?

We can do the mod on KennyBoxster (hopefully that's O.K. with him) and see the difference between bone stock and Stage 1, like I have now (just a filter, screen, and MAF with stock throttle body connector), and stage 2 - which is drying (so don't speak too loudly or you might wake it up). I will post a pic soon. You up for it Kenny?

* No warranty expressed or implied. Do this modification at your risk. And IF you decide to do this, for goodness sake, disconnect the battery BEFORE touching the MAF!
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Old 11-01-2012, 02:24 PM   #11
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Quote:
Originally Posted by Ghostrider 310 View Post
I tried to google the theory of why the inlet is shaped that way, I didn't get far as I didn't know how to approach the subject too well. With the resume of the owner thread, someone on here must be able to explain whether that "trumpet" style inlet accelerates or shapes somehow the incoming air. I'd also like to know what the 987 intake is like as I haven't been in there to check the air filter yet.
There is an answer out there and it rests in the wonderful world of computational fluid dynamics (CFD) as this allows for simulating the dispersion of air into a space. It can be a painful process to read if you are not familiar with the math that goes with it. However, as it is well known...if you have to say it with a 15 dollar word when a 3 dollar word would work...you don't know your stuff.

I think you will find this paper from Yong Yi and Fluent Inc. is both a good read (easy) and informative.

http://www.erc.wisc.edu/documents/symp05-Yi.pdf
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Old 11-01-2012, 03:48 PM   #12
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Thanks for posting that, way cool.
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Old 11-01-2012, 06:54 PM   #13
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Interesting link. This may also be interesting to those that have modified their intake to be less restricting.

Last edited by Kenny Boxster; 11-01-2012 at 06:58 PM.
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Old 11-02-2012, 04:40 AM   #14
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Anyways, I bought the AFE Cold Air Intake. It replaces the stock filter with a performance reusable filter. It replaces the stock intake hose and gets rid of the silencer. It is about the same size as the stock intake hose. Maybe a couple millimeters larger in diameter than stock.

I noticed a slightly louder idle sound and a louder engine sound at 4000+rpm. But as expected, I did not feel any difference in speed. These Aftermarket intakes barely make any difference.

Complimentary mod: clean your throttle body with alcohol or electric parts cleaner while you have the stock intake hose off.
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Old 11-02-2012, 04:45 AM   #15
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O.K. I feel like the dumbest one in the room now. Anyone for a recess, I was always good at recess.

@Eric G - how does a rocket scientist ever become a road racer? You are way to smart for that! On the presentation, about the second or third slide from the end there was a graph model about larger size intake, and then CFD model showing a larger diameter tubing was called for…interesting that fluid would also serve helpful for mixing gases.

Here is the existing problem with airbox….it shows the piece that is removed is the the receiving end of the snork. It has a 3" x 4" opening….the larger oval part is 8" on bottom, 5" on top and 3.5" in height - that is the intake size the modded air filter uses….


Here is a pic of the "air path" that snakes around inside your Factory airbox…take a look! It is a little hard to see...


Same pic but the arrows highlight with the path the air has to take…


Here is where the filter resides, most of us know this part as we see it when we change the air filter…what you did not know was the "long road" the air is taking to get to your throttle, where it makes the power! Talk about the long way home…


This is where the air is compressed or "flatlined" as I call it. The hole next to the filter where the air flows over the air filer is coming out of is only 2" X 5"!! This SEVERLY RESTRICTS air flowing over the filter…and thusly into the engine.


Anyway, all I know is….I mod practically every car I have ever owned with an air intake. This one is no different, sorry to you die-hard stock fans.

At least now you know what I was referring to when I said airflow is like an "old river" it bends back upon itself….what a waste but it was most-likely done to reduce sound! Just thought YOU SHOULD KNOW
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Old 11-02-2012, 08:00 AM   #16
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ok.

it’s all about moving air.

it’s all about math.

how much air is moving? for a 3.2 liter at 7200 rpm?

four stroke engine, so cylinder fills every second rotation, so moving 3.2 liters / 2 = 1.6 liters per rotation. multiply by 7,200 rotations per minute = 11,520 liters per minute. 192 liters per second. that’s a lot of air.

one could reckon that even small inefficiencies, obstacles, etc., in the intake get magnified when working with such relatively large volumes. fyi, a 1% loss on a 250 hp engine is 2.5 hp.

192 liters per second. that’s called the flow rate, where flow = volume over time. in our case this is also proportional to cross-sectional area of the piping, as air has to flow faster to move through a smaller passage. think about it; you have a pipe that you are drawing air through. flow in = flow out. now constrict the tube in the middle, creating a smaller diameter in a section of the pipe. flow in is still = flow out, but at the constriction the air will have to accelerate to pass the same volume of air in the same amount of time as in the sections of pipe before and after it.

using math, this presents as:

flow = volume / time
volume = area x distance
therefore, flow = area x distance / time
but, velocity = distance / time
so, flow = area x velocity

so, with flow being constant, a smaller area creates a higher velocity.

math.

another thing you would have noticed if you actually did the pipe constriction thing above was that it was harder to draw the air through the constricted pipe. that is because accelerating the air is work, and work requires energy, and this energy is lost as soon as the air slows down (decelerates) on the other side of the constriction. wasted energy. exactly what we are trying to avoid. making the engine do extra work that it doesn’t have to. that is why most aftermarket intakes use larger diameter, equal diameter components.

so why would porsche do this to a performance car?

well, there are benefits to accelerating the air in the intake. if I can accelerate my air so that it is rushing into the cylinder instead of being sucked in then my engine will work less and i might actually get more power from improved cylinder fill on each rotation. in fact, if you open your engine and look at the intake runners that feed each cylinder, you’ll see that they taper slightly as they get closer to the engine. taper = reducing diameter = increasing velocity of air. porsche is working for us.

thing is, that intake valve on your cylinder isn’t always open, and when in closes you have that rushing air slamming into it and bouncing back. this forms a pressure wave that moves back up the intake and can impede airflow. what to do about that? well, if done properly, the lengths of the intake runners can be set such that the air bouncing back arrives just as one of the other valves open, using the bounce-back pressure wave to increase cylinder fill even further. that’s called a tuned intake.

note that you can tune only for a small range of rpm. the tuning is based on the length of the intake runners and the velocity of the air, but as we found above, velocity = distance over time, and changing the rpm changes the time component of the equation and throws the tuning off. all is not lost, however, as porsche has thought about this as well. if you go back to your engine, you’ll see the intake runners heading to each cylinder as discussed previously, but you’ll also see each bank of intake runners joined by two tubes. one of these tubes is called the ‘resonance tube’ and has a vacuum-operated flapper valve in it. the purpose of this resonance assembly is to open the flapper valve at higher rpm, effectively changing the intake runner length and ‘re-tuning’ your intake for higher rpm.

booyakachaka.

a few more points.

since the tuning of the intake is only working 100% for two small rpm ranges, there will still be bounce-back pressure waves occurring and impeding airflow. what you need is some way to get this wave out of the way so that your intake can be as efficient as possible. if you look at your oem intake piping between the throttle and the air box you will see a resonance chamber on it (or even a little appendix-like chamber if you have an earlier car); this is where porsche tries to stall-out the pressure wave to keep the intake as efficient as possible. my theory (ie, not science or fact) is that the great intake sound you hear when you remove this chamber and put on an aftermarket intake is actually the pressure wave interacting with the intake air; you are literally hearing your intake become less efficient.

the plenum (the chambers that join the runners together) should be designed to be at a constant, positive pressure, so that air is always available to feed the runners. the best way to get positive pressure is to have, as before, air accelerating into the plenum. similar to the intake runners, this is achieved by having your intake piping gradually reducing in diameter as it approaches the plenum, and this is where you see the porsche intake on the 3.2 liter engine reducing from 3” at the airbox to 2.66” at the throttle.

the airbox gets treated similar to the plenum, as both serve as air supplies to piping designed to accelerate air. as such, the airbox should be at a constant, positive pressure. again, to get positive pressure in the airbox we have to accelerate air into it. to do this we have a restriction (the snorkel) on the intake.

another consideration is how solids perform in a fluid. basically, accelerating fluids tend to ‘pick-up’ solids, and decelerating fluids tend to drop solids. the mississippi delta is full of mud because all the dirt that got picked-up by the faster flowing river upstream gets dropped when the river slows down to meet the ocean. similarly, decelerating the air in your airbox prior to hitting the filter allows all that dirt/bugs/cigarette butts to settle out before clogging the filter (or setting it on fire).

so, porshe is perfect, right? then why do folks show hp increases with aftermarket intakes, larger throttles, removed snorkels, etc.?

apples to apples. the boxster is a light, underpowered car (relative to the 996) designed to perform in a low speed environment (cities, twisty tracks). as such, porshe tuned the car to extract as much lower rpm torque as possible from the smaller engine. the tuning (resonance chamber, airbox/snorkel, decreasing diameter intake piping, etc.) is designed to maximise performance in the 2,000 to 4,000 rpm range AT THE EXPENSE of high rpm hp. that is, at higher rpm the resonance chamber on the intake piping that was serving to reduce the pressure wave at 3,000 rpm is now just a place where 192 liters per second have to expand and contract (wasted energy) before getting to the engine (remember that, similar to intake runner tuning, the most effective placement of the resonance chamber will vary with rpm, yet it is fixed in place). the smaller throttle body and snorkel designed to accelerate air into the plenum and airbox, respectively, in order to create positive pressure are now just obstacles to airflow as they become too small to efficiently move the volume of air we are trying to move.

if you go back and look at the dynos of aftermarket intakes, throttles, etc, first put on your ‘wishful advertising’ spectacles to try and see through all the vendor murk. next, notice that none of them show any gains, and some show losses, at lower rpms, and the benefits only start to appear at higher rpms.

and this is time I will never get back.
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Old 11-02-2012, 08:41 AM   #17
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Originally Posted by The Radium King View Post
ok.

it’s all about moving air.

it’s all about math.

how much air is moving? for a 3.2 liter at 7200 rpm?

four stroke engine, so cylinder fills every second rotation, so moving 3.2 liters / 2 = 1.6 liters per rotation. multiply by 7,200 rotations per minute = 11,520 liters per minute. 192 liters per second. that’s a lot of air.

one could reckon that even small inefficiencies, obstacles, etc., in the intake get magnified when working with such relatively large volumes. fyi, a 1% loss on a 250 hp engine is 2.5 hp.

192 liters per second. that’s called the flow rate, where flow = volume over time. in our case this is also proportional to cross-sectional area of the piping, as air has to flow faster to move through a smaller passage. think about it; you have a pipe that you are drawing air through. flow in = flow out. now constrict the tube in the middle, creating a smaller diameter in a section of the pipe. flow in is still = flow out, but at the constriction the air will have to accelerate to pass the same volume of air in the same amount of time as in the sections of pipe before and after it.

using math, this presents as:

flow = volume / time
volume = area x distance
therefore, flow = area x distance / time
but, velocity = distance / time
so, flow = area x velocity

so, with flow being constant, a smaller area creates a higher velocity.

math.

another thing you would have noticed if you actually did the pipe constriction thing above was that it was harder to draw the air through the constricted pipe. that is because accelerating the air is work, and work requires energy, and this energy is lost as soon as the air slows down (decelerates) on the other side of the constriction. wasted energy. exactly what we are trying to avoid. making the engine do extra work that it doesn’t have to. that is why most aftermarket intakes use larger diameter, equal diameter components.

so why would porsche do this to a performance car?

well, there are benefits to accelerating the air in the intake. if I can accelerate my air so that it is rushing into the cylinder instead of being sucked in then my engine will work less and i might actually get more power from improved cylinder fill on each rotation. in fact, if you open your engine and look at the intake runners that feed each cylinder, you’ll see that they taper slightly as they get closer to the engine. taper = reducing diameter = increasing velocity of air. porsche is working for us.

thing is, that intake valve on your cylinder isn’t always open, and when in closes you have that rushing air slamming into it and bouncing back. this forms a pressure wave that moves back up the intake and can impede airflow. what to do about that? well, if done properly, the lengths of the intake runners can be set such that the air bouncing back arrives just as one of the other valves open, using the bounce-back pressure wave to increase cylinder fill even further. that’s called a tuned intake.

note that you can tune only for a small range of rpm. the tuning is based on the length of the intake runners and the velocity of the air, but as we found above, velocity = distance over time, and changing the rpm changes the time component of the equation and throws the tuning off. all is not lost, however, as porsche has thought about this as well. if you go back to your engine, you’ll see the intake runners heading to each cylinder as discussed previously, but you’ll also see each bank of intake runners joined by two tubes. one of these tubes is called the ‘resonance tube’ and has a vacuum-operated flapper valve in it. the purpose of this resonance assembly is to open the flapper valve at higher rpm, effectively changing the intake runner length and ‘re-tuning’ your intake for higher rpm.

booyakachaka.

a few more points.

since the tuning of the intake is only working 100% for two small rpm ranges, there will still be bounce-back pressure waves occurring and impeding airflow. what you need is some way to get this wave out of the way so that your intake can be as efficient as possible. if you look at your oem intake piping between the throttle and the air box you will see a resonance chamber on it (or even a little appendix-like chamber if you have an earlier car); this is where porsche tries to stall-out the pressure wave to keep the intake as efficient as possible. my theory (ie, not science or fact) is that the great intake sound you hear when you remove this chamber and put on an aftermarket intake is actually the pressure wave interacting with the intake air; you are literally hearing your intake become less efficient.

the plenum (the chambers that join the runners together) should be designed to be at a constant, positive pressure, so that air is always available to feed the runners. the best way to get positive pressure is to have, as before, air accelerating into the plenum. similar to the intake runners, this is achieved by having your intake piping gradually reducing in diameter as it approaches the plenum, and this is where you see the porsche intake on the 3.2 liter engine reducing from 3” at the airbox to 2.66” at the throttle.

the airbox gets treated similar to the plenum, as both serve as air supplies to piping designed to accelerate air. as such, the airbox should be at a constant, positive pressure. again, to get positive pressure in the airbox we have to accelerate air into it. to do this we have a restriction (the snorkel) on the intake.

another consideration is how solids perform in a fluid. basically, accelerating fluids tend to ‘pick-up’ solids, and decelerating fluids tend to drop solids. the mississippi delta is full of mud because all the dirt that got picked-up by the faster flowing river upstream gets dropped when the river slows down to meet the ocean. similarly, decelerating the air in your airbox prior to hitting the filter allows all that dirt/bugs/cigarette butts to settle out before clogging the filter (or setting it on fire).

so, porshe is perfect, right? then why do folks show hp increases with aftermarket intakes, larger throttles, removed snorkels, etc.?

apples to apples. the boxster is a light, underpowered car (relative to the 996) designed to perform in a low speed environment (cities, twisty tracks). as such, porshe tuned the car to extract as much lower rpm torque as possible from the smaller engine. the tuning (resonance chamber, airbox/snorkel, decreasing diameter intake piping, etc.) is designed to maximise performance in the 2,000 to 4,000 rpm range AT THE EXPENSE of high rpm hp. that is, at higher rpm the resonance chamber on the intake piping that was serving to reduce the pressure wave at 3,000 rpm is now just a place where 192 liters per second have to expand and contract (wasted energy) before getting to the engine (remember that, similar to intake runner tuning, the most effective placement of the resonance chamber will vary with rpm, yet it is fixed in place). the smaller throttle body and snorkel designed to accelerate air into the plenum and airbox, respectively, in order to create positive pressure are now just obstacles to airflow as they become too small to efficiently move the volume of air we are trying to move.

if you go back and look at the dynos of aftermarket intakes, throttles, etc, first put on your ‘wishful advertising’ spectacles to try and see through all the vendor murk. next, notice that none of them show any gains, and some show losses, at lower rpms, and the benefits only start to appear at higher rpms.

and this is time I will never get back.

@T Rad King, Love the math! And while I agree up to the 192 Liters Per Second, and can concur with most of what you are saying, there is another element that needs to be considered…I will USE the higher RPMs and the needs of my engine are not as great (I can afford SOME lost HP in lower RPMs) to GAIN the TOP HP possible, using more airflow, concepts that you have described to the "T", no pun.

Another aspect that is important is linear airflow, straightening or smoothing the air…air turbulence. There is known work out there that DID NOT exist when Porsche designed this car, so what would be the reason not to use that technology?

What other tuners have discovered, again more recently than when our cars were designed, was that by using a device to "establish a more uniform airflow" the horsepower gains are derived from more fluidity over the MAF, allowing the car to adjust the optimum performance.

Since you know of whence you speak, check out this thread (it for Tuners for V-8s, concept still applies):

100mm Maf kickin my Butt!!! - HP Tuners Bulletin Board

Let us know if the part they are speaking of, in terms you we understand, will be of any benefit. I am unable to test it today, so i would like your opinion.
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Old 11-02-2012, 08:57 AM   #18
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TRK -

It is true that you won't get the time back, but when you die, you will achieve total consciousness.

So you have that going for you, which is nice...

Thanks, your post was very helpful!
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Old 11-02-2012, 09:18 AM   #19
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Originally Posted by The Radium King View Post
first put on your ‘wishful advertising’ spectacles to try and see through all the vendor murk. next, notice that none of them show any gains, and some show losses, at lower rpms, and the benefits only start to appear at higher rpms.

and this is time I will never get back.
Indeed you should always be skeptical when taking in manufacturer's claims. That being said, one of my favorite quotes is there are lies, damned lies, and statistics. Your application should be catered to your driving habits, wants, and needs, so some folks want prefer higher end horsepower, and some lower end torque. Interestingly enough there's a graph of a guy who did a CAI and scoop to draw in more air. I don't thing there's any ulterior motive for this guy to fabricate his results, unless of course he was paid by kokeln, which I doubt.
http://www.m96infosource.com/site/2011/04/21/boxster-s-ram-air-intake/

In conclusion, there's merit in a less restrictive airflow, but some folks have different preferences in the power bands and torque ranges.

Last edited by Kenny Boxster; 11-02-2012 at 09:20 AM.
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Old 11-02-2012, 09:24 AM   #20
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Are you trying to say Porsche didn't know you have to have smooth laminar airflow to the MAF for accurate readings? This is NOT new information, and has been know for decades in automotive and industrial flow applications. The only reason honeycomb "air straighteners" had to be used on that site is because they totally screwed up the factory intake flow characteristics.

I'm not saying the factory intake can't be improved for high RPM power, but internal or external airflows are not always as intuitive as you might think. The only way to be sure of your results is by detailed calculation, CFD, and objective testing.
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