OriginalMadMax

I've seen heat shields in a speed shop in Oakland's Chinatown. They seemed to be made of aluminum. The problem as I see it is two-fold: First, the heat shield itself will heat up, and second, hot air can get around it because it isn't a closed system. I STILL say remove the heat from under the hood! Everything else is just dancing around the problem, which is build up of temperature there.
How could we test this? Well, maybe see how long it takes the temperature to drop under the hood when the car is shut off, then from the same temperature, see how long it takes with the hood cracked open. If it's faster when the hot air escapes, then that would seem to be worth pursuing. Kind of a no-brainer, I think; just a PITA to cut into the hood so it looks good ...

SLC I30t

iTrader: (1)

If I wanted to get an accurate temp reading on my CAI where would I check it from?
http://images.cardomain.com/installs...48_23_full.jpg
The Filter elemtent is about 7 inches below the bend where it fades into black.

I'm serious, I am intersted.

rcrdps

What ya'll might consider is just using really large tube for the CAI....say maybe 3.5 to 4 inch or so.

Gene

Str8ridin

You could run the wire down the tube and insert the temperature gauge inside the filter at the end of your CAI. However, the possibility of the tube warming up and transferring the heat to the air as it comes through the tube exists, so I suggest being creative enough to place the gauge in front of the throttle body.

ptatohead : A Heat shield is an excellent idea. Mugen makes a plastic one that essentially encapsulates the entire cone filter and is connected to a tube that curves down near the fender. It's exactly like the stock air box, but coned shape to hold the cone filter. Kind of like this (excuse the rice)
http://www.streetsourcemall.com/stor...ugenintake.jpg

In my opinion, if you have an effective heat shield (like the one mentioned above)and combine it with the a good OSCAI set-up, this could be the most efficient way to use cone filters.

Here is another heat shield that I found interesting:
http://integra.vtec.net/geeser/megam...sheild_fan.jpg

All though they come in different shapes and sizes, I think they shouldn't go over looked.

JAIMECBR900

I still don't understand why it seems like everyone is trying to go the long way around to reach the same place. Why not just get and use the CAI in the first place? It gives you the shield from the under hood heat that you seek, it gives you constantly lower air temps., and the benefits of increased velocity and volume. Am I missing something? Is it because the length of the intake itself that you guys are thinking is some kind of draw back? I'm not flaming here, this a leggit question. It just seems to me that all the ideas you guys have, even though I personally think they are very forward thinking, are all going back (essentially) to the same thesis of colder air intake.

poorcollegeboy

if you read the past posts to this thread you will find that a pop charger will out perform a CAI in the higher end. that's why people are trying to bring the cold air to the pop charger. they want the best of both worlds - cold air for lower end and high unrestricted volume of air for the higher end.

poorcollegeboy

hey.... that engine bay looks awfully similar to a maxima's. do you think the heat shield will fit into a maxima (with little modding)?

ptatohed

iTrader: (12)

Well said.

JAIMECBR900

I did read the post. I don't read anything about restricted air in the CAI. I think this is an assumption. That is the reason why on my last thread I was asking whether you guys knew something about the length of the tube in a CAI set-up having any adverse effects. According to the post and it's findings, ONLY the CAI had both lower temps and sustained the lower temps through out the entire test which afterall is supposed to be the desired effect. Both the Pop and OSCAI were vulnerable to temps changing drastically and were very dependent on the car to have been moving for a distance to obtain their lowest temps. It just seems to be two differing schools of thought here at work. One thought is that the length of the air has to travel from a CAI is longer than the length of travel on a Pop and that, somehow, is a detriment to high end performance. Second thought is that the length of travel is not as much a difference, if any, as the temp of the air the intake is ingesting and how it relates to engine performance. As I stated before, I'm not trying to put anyone's choice of intake down at all. I think that if someone picks ANY intake over the stock one they will reap benefits which would make that choice a wise one in any sense. The amount of those benefits seems to be the subject that seems to be leaving people a lot of room for interpretation.

poorcollegeboy

i know i'm beating a dead horse here but......

CAI PROS - better low and mid range power because...
1. sucks in cold air (duh)
2. creates a "static ram air" because more air is readily available in the long tubing

CAI CONS
1. long tube creates TURBULENCE in higher end

POP CHARGER PROS - better high end power because...
1. less tubing to create turbulence and restriction

POP CHARGER CONS
1. air comes form engine bay (warmer = less power)

OriginalMadMax

OSCAI PROS
1. still keeps the shorter intake tube
2. sucks in cool air, and stores it in tubing during idle (static ram air)

OSCAI CONS
1. Mixes warmer air with cooler, mostly at idle.

rcrdps

static ram air??? Isn't that kind of an oxymoron(sp?)?

Ok for the tubing length with diameters being equal:
Long = Good ram effect at low rpm. Restrictive at high rpm.
Short = Good high rpm power since there is less restriction. No ram effect at low rpms.

Tubing diameter with lenghts being equal:
Small = Mostly the same as long tube
Large = Mostly the same as short tube

Now,.. we all agree cold air is good, so,...

Want your low end? Driveability? Go with the average CAI kit.

Want high end? Peak HP? Make your own CAI kit except use larger tubing. With out a scoop on the hood we really can't make the tubing shorter, so just make it larger instead. It's not an exact swap, for short tubing, but close enough.

Gene

JAIMECBR900

I follow what you guys are saying, but I still don't understand how you guys are coming up with the results.

See, the engine will only pull air into the intake as the demand is needed. i.e. more as the load, speed, rpm's, etc. as opposed to at idle. The key here comes in not in the fact that the engine needs X amount of air to work, but how can we get X+ and it be as cold as possible to make for more efficient combustion. In other words, what we are trying to accomplish is simply to improve performance we understand we need to get the most amount of cold air into the engine as it demands it so it can put out the most amount of HP.

I still don't understand how just the length of the tube ONLY will impede the desired result. I would theorize that it does the opposite since a longer tube will increase the velocity of the air being taken in (i.e. longer barrel in a gun yields higher velocities as compared to shorter barrels.). As for volume, that is directly proportional to the demand and the size (diameter) of the tube being used. The only way for a longer tube will not to yield the same volume (as long as diameters are kept equal) as a shorter one is for the receiving end (in this case the engine) to basically run out of "sucking" power. As for "restrictions", there is no more restriction on my CAI between the filter and MAF than ther is between your Pop and the MAF. If you are theorizing that the engine peeters out at the top ("sucking power") and therefore it's easier to pull air thru the pop as opposed to the CAI AT THAT SPECIFIC MOMENT IN TIME then it makes sense about your theory of top-end advantage. If that is what you guys are saying, then I will stand corrected. If not, It just doesn't make common sense to me.

Str8ridin

Take a long hose and short hose for example. If you were to 'suck' air in from the long hose, it would require more effort than sucking air from a shorter hose. So, in theroy, a CAI with the longer tube dimishes the point of have a less restrictive air filter.

So, yes, when the engine is peeking and every bit of HP is needed, a less restrictive system will help.

rcrdps

The gun barrel isn't really a good example. That would be good if we were talking about mixture and stroke...ie a longer stroke would probably benefit from a richer mixture. or a longer barrel is good because of the slow burning explosive.

Pretty much, as long as we're not talking temperatures, treat an intake just like you treat an exhaust. They're both flowing because of a pressure difference on either side. Just like you can tune for rpms with exhaust length, you can tune for rpms with intake. That's why things like variable intakes work. The reason it can be rammed is because the valves aren't always open. Otherwise we would want zero intake lenghts. Since they are closed part of the time when they're opened the air starts flowing down the tube. If the tube is long enough, when the valve closes, the air keeps flowing(momentum)and it rams up against the valve. When the valve opens again the air is there waiting for it. The longer the tube the more volume you have traveling at a high speed(you use the small tube to get the speed). To get the most out of our ram effect, we want to have the highest pressure at the valve when it opens. The highest pressure will come just as the volume of air is coming to a complete stop in front of the valve, and is about to start going the other way. If we open the valve right then, it will take in that compressed air and also create a slight vacuum there which will start the air moving in toward the valve again for the next cycle. If the intake is too long it will take more time to accelerate all that air and it won't be at it's highest presssure when the valve opens. If it's too short the air will have already started going the other way(reverse) reducing the pack of air at the valve. So you must tune the length of the intake to match how fast your valves are opening(or rpms).
Now for the diameter. If the rpms are high, there will be a higher vacuum at the valve. If the diameter is too small not as much air will reach the valve to fill that vacuum before the valve opens. If the diameter is too big, the speed won't be up and will reverse direction and you lose the ram effect.

Notice that this kinda is different from what I said in my last post. That's why I used the words "Mostly". I didn't feel like explaining it then. Hope this helps. And hopefully I get this out in time to not repeat anyone.


Gene

OriginalMadMax

Not really. The ram effect really only works when the car is moving, so that the column of air in the tube is being pushed towards the intake. This is especially true on the OSCAI, since the under-hood filter draws air from ambient sources, not just through the tubing. Therefore, whatever air is in the cold air intake will not necessarily be used, at least to a degree any greater than engine compartment air, but once the car is moving the cold air will be pushed through the tube faster and will cool the intake more quickly. So, it is relatively static (not moving) at stops, then gets rammed when moving. Sort of makes sense, I think.

poorcollegeboy

pop chargers have been DYNO'd to have higher HP than CAI in the higher end.

dmbmaxima2k2

iTrader: (1)

and weighing 130 should be a mod. i weigh 230 that's 100lbs and at least a .1 on your 1/4

catman316

where did you see those dynos results??
Do you have then? post then if so!!

ptatohed

iTrader: (12)

O.k., don't laugh at me guys but I remember my physics teacher telling us that air through a smaller opening is colder than through a larger opening. He then gave the example of putting your lips tight (as if you were whistling) and blow on your hand vs. opening your mouth wide and blowing on your hand. Think about it, when you want to cool off your coffee, you 'tight lip' blow, when you want to warm your hands in the winter, you 'open mouth' blow. Am I making sense? My question is, does this play a role for our car's intake? Should we be using smaller diameter intake tubes for colder air? But then we'd have less air, I guess. Anyway, just thinking...

Jime

iTrader: (10)

Regardless of how you hold your mouth you are still blowing the same hot air. Its like a fan blowing on you it doesn't make you cooler it just makes you feel cooler. Similar to the wind chill factor it only makes a difference on how it feels to human skin not and not metal etc. It is still the same temperature regardless of the wind chill factor.

SLC I30t

iTrader: (1)

I must be dumb, because I thought you put your lips together to blow on coffee to increase the velocity of your breath to cool the coffee. I but I think you have a good analogy though. I would think of it this way-If any of you guys run (with your legs)-try and breath in and out of your mouth, then try and breather through a snorkle. I think that unless your CAI is getting blow by air. I don't think its getting any benefits except cooler air. There is a longer straw for your car to breath through. I can see how it would hurt dyno's, because they only benefit while driving. So in a dynojet I would assume that the POP charger would be better since the hood is up while you are dynoing. But put the 2 cars side by side on a track and I think that trap speeds on the CAI will be higher than the POP. Infact that is my experience on the track is almost a 1.5mph increase of trap speed and and .05-.10 increase of time reduction. These are on an average of course. But call me stupid, but what is an OSCAI? I know what the PRCAI is...but OS?

ptatohed

iTrader: (12)

Ha-Ha! I asked the same question SLC (although offline because my nuts aren't as big as yours - lol) and, you know what? I still don't know! I think I know what it is, but like you, I just didn't know what the term meant. It is when you use a Pop-Charger type intake and you bring oustide air to it, coorect? Now for the definition. The CAI is Cold Air Intake, obviously, we all know that. But OS? My absolute best guess before asking was 'OutSide'. Well, Ben told me 'Ooglie Stock'. That makes no sense to me! What is ugly (er excuse me ... ooglie) about it? Just because you use Home Depot PVC to 'homemake' one? And Stock? That really makes no sense! What is stock about it?! We really need a new term.

poorcollegeboy

it's not the smaller tubing that will get you colder air. it's the pressurized air. when you "blow on your coffee" the velocity is not what's ultimately making it colder it's the pressure you create when you decrease the diameter that the air is coming out (that's why your cheeks puff out). think of any air conditioner.... what makes them pump out cold air? the compressor. so if you want to acheive colder air using tubes, you have to somehow make the air pressurized (possibly have air running from a larger diameter tubing into a smaller <~~ won't get the greatest decrease in temp though)

Bman

Actually the air conditioning compressor doesn't cool anything down by pressurizing it. I'll be honest and thank http://www.howstuffworks.com/ac1.htm
Also, like in the trail of a jet plane, low pressure air is colder, causing condensation or icing on some surfaces. This kinda makes sense also if you think of air molecules moving around with X amount of heat energy each. The fewer molecules (low pressure is low density) the less energy per volume.

Also, that blowing on coffee analogy is kinda whack (prof's fault), because it feels cool on your hand because of wind chill, and cools coffee in sort of the same way. Also, it moves much more luke-warm air over it, which helps too. I don't think that blowing the air with your mouth can create enough velocity to noticably lower the air temperature (which is warm already from your body heat).

JAIMECBR900

Guys, good try on the analogies but what does cooler air do to the human body as far as performance? Nothing. The analogy of the snorkel does put a little into light about the length of the tube though. Shorter vs Longer. I personally still think the CAI is going to be the best because it has been shown to have the "colder" temps for the longest amount of time. That is what we are after. The only debate in my mind is the one about the length of the tube and it's effects on high end performance. As for dyno results, I have yet to see one let alone a reliable one. Remember, to judge the difference between two competing parts you would have to install each part and dyno on the same car the same day. If you don't and compare car A with this and car b with that even if it's the same day, the experiment will not be accurate. If you compare car A one day with a part and same car a with another on a different day, this won't be accurate either. So, until someone takes the time and dyno's the same car on the same day with any of the different parts involved, it will not be an accurate experiment. The debate continues 'till then...

Rob'sAE

Why not just double the diameter of the CAI tube, where as to reduce the friction associated with the longer tube? Create less vaccume(which is always good) and still be able to pipe in colder air? I had read a very good article in which a guy did vaccume and pressure experiments on his audi (i think it was an audi) and proved that removing as much restriction to flow and increasing pressure was very benificial. He proved that when there is a vaccume the engine is having to work to suck the air, instead of it just being there. A POP just about eliminates vaccume, but does not introduce a colder air charge, but actually might increase hotter air(over stock). A CAI (or OSCAI-Ogglie Style Cold Air Intake) flows colder air but introduces much more air friction increasing vaccume. I think the best solution would to be a CAI but increase the intakes diamater to the point where vaccume would not be able to be created. Possibly about 4-5" in diamater. When it gets to the MAF it would shrink down smoothly to fit, basicle a POP with a cold air tube. (this thinking is with the air filter at the opening of the CAI) Then because of the shape of th tube and the constriction of it at the MAF, at speed it would build up some pressure, therefore increasing top end power also, similar to a scramjet or ramjet engine. The tube would also have to be somewat insulated because of decreased air velocity the pipe would have a tendancy to heat up standing still, maybe double walled, or wrapped with some kindof insulator. This is all just my part of this theological physics class...

JAIMECBR900

The idea of larger diameter would possibly work in your thesis. Except you did not consider (mention) the fact that some of the guys that are saying the drawback to a CAI is the length of the tube decreases top end due to engine not having as much vaccum power at the top end thereby assuming that a shorter intake tube would benefit in that situation.

I think that if the diameter is too big you will begin to get into the situation of negating the ram effect. Kinda like the Law of Diminishing returns. We may get increased volume, but less velocity. I think that the diameter (bigger) of the intake may not yield as much benefits as does the temp of the air itself, velocity, and volume.

Bags

iTrader: (3)

Ok, Time for the dumb guiy to say something. Sorry I read as much as I could, so if I repeat anything forgive me.

Jamie on your statement above, I completly agree with you. So why not extrude hone your TB,Intake manifold,exhaust manifold and increase the size of the CAI tubing?

OR in the same concept Bore everything?

I am sure there will be that 1/10 of an inch that will be to big, but try a 3 inch pie and a 3 1'4 then a 3 1/2 and see what happens?

Again doing it to your TB and the rest of your motor I think would be key. But my 2 cents

nardo'89SE

what intake puts down lower quarter mile times, and higher trap speeds?

ptatohed

iTrader: (12)

A SuperCharger!



(Gosh I love giving that answer )

nardo'89SE

i know its a newbie question, the classic "should i get a CAI or a pop" question, but there is no answer because so many variables play into it, for me the answer was easy, i got the CAI for my VG because you can do both with the CAI, so i can switch back and forth and wonder if i can tell a difference

Carlos A

Greetings,

Pretty interesting analysis. All filled with very inventive solutions and many theories of operation of mass velocity, pressure and temperature, I am proud of you!

Perhaps I could add some more:

1- The temperature of an object drops at a rate proportional to the speed of the air that passes on its surface.

2- The change from a bigger diameter to a small diameter produces a change in pressure and the result is a change in velocity.

3- The POP Charger, or Stillen High Velocity intake, use a Ventury stack adapter for the same purpose (the doughnut at the MAF). This is a contributor for the POP gains.

4- The CAI does provide an integrator (a dampener, a capacitor if you are an EE) in the system as it stores air in the tube but the supply is modest in nature an is not enough to meet the demands of the engine on a hard acceleration (limit is a step function.) Thought the idea of storage is valid.

5- The design of an intake that can have the properties of storage, temperature and velocity is not trivial because all these processes and their control are non linear and even though are in some cases related have different slopes.

That is to say (for example) that when one attempts to generate storage (say a chambered system) there cannot be flow velocity (that is from input to output,) in the same manner, one can create velocity by changing pressure and drop the temperature but cannot create storage. One of these must be sucrificed. My take is the storage.

A simple design would probably be on that uses the Ventury Stack of the POP charger, and a 5" diameter straight tube that extends the filter to a place in the car that gets cold air this way the large tube can provide some storage and be resonant at higher speeds while keeping the turbulence low. The air from the medium (engine bay or outside) will change velocity at the MAF interface and lower the temperature of the sensor. The key point is to maintain the tube as cold as possible, but there are other means to do that.

victor

iTrader: (1)

i've read a lot the past couple of days on intakes.

my plan is to use the stock intake, but change the piping (resoantor) in between the MAF and the TB, to a larger diameter 4.0"-4.5". on another thread someone recommended that to me, saying that the more volume the better. with the bottle necks being the MAF and the TB diamters. what do you all think of that??

SLC I30t

iTrader: (1)

well if you want the bottle neck to create velocity, then just keep the 3" vacuum port piece but make it very short, mount the MAF on the otherside and then have your 4in plentum that will stretch to your filter.

dmbmaxima2k2

iTrader: (1)

that's gonna be tought to bottle neck back down, but keep us posted maybe it's somethign i can look into doing.

-steve

victor

iTrader: (1)

so the only thing i essentially will do with what you say, is to make the piece between the MAF and the TB really short? and everything else will stay constant?

huh?? i didn't get the first part of your sentence. but sure i'll keep you posted anyway.

dmbmaxima2k2

iTrader: (1)

it's gonna be tought to custom make an intake that goes from 3 inch maf to 4.5 inch chamber back down to 2.75 for the maf.

ptatohed

iTrader: (12)

You guys ever see that Supra who made an intake hole right through his headlight? It's pretty sweet. I guess you can't get any more 'ram' than that! I thought about playing around with that on my old '96 headlights (I upgraded to '97) but I don't know about cutting glass and all that. Seems pretty hairy. But it would be cool.

victor

iTrader: (1)

ok. i think i get it, your saying it's going to be tough to make one... yeah, maybe. we'll see.