Stock airbox IS a cold air intake CAI

[chimchim]

I don't give a crap about bling. I only want to spend $$ on stuff that's actually gonna do something. So I've been trying to figure out why CAI's don't do much better over the stock intake. Here's the conclusion I've come to... and please comment. I also believe that the Honda engineers did things for a reason; they aren't stupid. So if you can "improve" their design, it's because you either have a different goal or more budget.

The stock intake on my 97 Civic EX already is a cold air intake.

Well that's what it looks like to me. The plastic piping, while bumpy on the outside, is about a 3" diameter smooth tube to the airbox. The airbox contains a flat ~6"x6" air passage area filter from the lower portion of the airbox. The airbox has a smooth 3" tube which sucks air from under the bumper in front of the right front wheel well. THIS IS THE COLD AIR LOCATION.

So:
- environment air enters the intake system at the underbumper corner, same as true CAI's.
- piping is about 3" diameter, same as many CAI's.
- advantage of this system is that the filter is located far away from the bumper intake hole and thus has a lot of immunity to splashes. (Who says that the cone has to be at the beginning of the intake anyways?)
- the closed airbox shields it from the under the hood engine heat; just like the Icebox intakes.

The only difference I see between the stock and aftermarket CAI's is the surface area of the filter. So, this leads me to believe that the "small, almost insignificant gains from a CAI" is because the stock intake actually shares almost everything in common with the aftermarket CAI's.

I've wondered why they but such small cone filters on the CAI's, as the surface area of the cones are not much more than the surface area of the flat stock filter. Since I'm guessing that the highest restriction in an intake (up to and not including the intake manifold) is the filter itself, I would contend that sticking a massive K&N cone filter (like those big 7" jobbers) on the stock system would get probably the same gains as a CAI intake system. (Of course there's logistics like size of the airbox and how to actually attach the filter.)

The other thing I'm considering doing is adding a scoop to the intake opening of the stock system at the bumper. At higher speeds, the scoop hopefully will increase the air pressure from what it was before, thereby reducing the work the engine does to suck air in.

I theorize that most of the "vaccuum" noise from CAI's comes from the thousands of itty bitty turbulance points as the air gets sifted through the filter mesh. Some, but much less significant is the noise of the air vibrating the pipe edges and bumps. Thus, the enclosed airbox will reduce the noise generated by the intake. (Which is good or bad depending upon who you are.)

So anyways, I think this is why aftermarket CAIs don't do much improvement to modern cars. Blah blah blah. I'm learning.

[JBEX]

I thought I was going crazy thinking the same thing. The aftermarket CAIs' tubes are smooth and polished where the stock airbox is plastic and rough I'd assume. That would probably result in lower air friction. I may be high too, but whatever the case, I'm glad I'm not the only martian around here.

And what of this "scoop?" what's that all about?

[whiteracer]

13 post between the two of them.

I so want to reply a lot more but work gets out it 5 minutes...so here goes the abridged version.
1. Yes colder air is located down by the bumper as opposed to higher in the engine compartment. Hence the reason why CAI are more popular. The most popular being the AEM CAI.
2. The plastic material the stock tubing is made of verses the aluminum piping AEM uses plays a big difference in temperature. The filter on the end on these aftermarket one's are better than the square block filter that is for the stock tubing.
3. The stock filter is very RESTRICTIVE. The basics of modding an engine are to provide better AIR FLOW. So the more air that can get in the engine (intake), the more exhaust can get out quicker (header/exhaust) giving more horsepower.
3b. Without the Intake, header, or exhaust (not just the muffler), there won't be much of a hp difference. The stock header and exhaust piping + muffler are very restrictive as well.
4. Going back to #3, many people make their own with nothing but a K&N cone filter, some aluminum pvc piping (i think) and a couple clamps to hold the filter to the pipe, and the pipe to the IM.

You are at least thinking, and have good points to back your argument up, except the fact that the stock intake tubing is very restrictive and even muffles some of the sound. With an aftermarket intake you can actually hear something different.

Cliff notes: stock piping = ridges = restrictive, different material aftermarket intakes = smoother piping = less restrictive, different material = aluminum = conducts less heat, keeps air cool.

[esp]

Originally Posted by whiteracer

13 post between the two of them.



Cliff notes: stock piping = ridges = restrictive, different material aftermarket intakes = smoother piping = less restrictive, different material = aluminum = conducts less heat, keeps air cool.

yes the stock intake is more restrictive, which means u are not gaining any power from the stock crap, by no way is it a CAI.


on a side note like 3100 some posts between us!!!

[94tegRS]

ok, isnt anohter big reason the stokc air intake system doesnt work as good because the air goes through the tune,. then enters the big black box, then goes through the tube again, I thought the whole reason for an intake is the air is filtered, then goes through one solid straight shot into your engine, and that big black filter box disturbs the turbulence or whatever youd call it, cuz Ive read even just the AEM bypass valve messes the air flow up enough to where a SRI wihtou the BPV would give more power than the CAI with the BPV.

[B16EJ1]

Originally Posted by chimchim

The stock intake on my 97 Civic EX already is a cold air intake.

Well that's what it looks like to me. The plastic piping, while bumpy on the outside, is about a 3" diameter smooth tube to the airbox. The airbox contains a flat ~6"x6" air passage area filter from the lower portion of the airbox. The airbox has a smooth 3" tube which sucks air from under the bumper in front of the right front wheel well. THIS IS THE COLD AIR LOCATION.

WTF is going on here? I know you AF regulars have installed your own intake and yet no one has the exact answer yet. First off n00b no the OEM intake system is not a CAI. Yes, on a CAI the filter and actual induction does take place in front of the wheel but no your OEM intake does not. Try actually taking the OEM intake off and you'll see what I mean. The OEM does go into the front wheel well area but it induction does not take place there. Why because there is a RESONATOR BOX in there. From the RESONATOR BOX a pipe re-enters the engine bay where the actual air induction takes place. Hence, NOT A CAI. Stop being a cheap ass.

[chimchim]

Hmmm...

2. The plastic material the stock tubing is made of verses the aluminum piping AEM uses plays a big difference in temperature. The filter on the end on these aftermarket one's are better than the square block filter that is for the stock tubing.

Yeah, I think I said this in my original post.

3. The stock filter is very RESTRICTIVE. The basics of modding an engine are to provide better AIR FLOW. So the more air that can get in the engine (intake), the more exhaust can get out quicker (header/exhaust) giving more horsepower.

Because of the restrictive paper filter, I bought the K&N drop in replacement. Obviously the K&N cotten mesh is better than the paper. I felt almost undetectable differences, with any (if any) ever so slight improvements at the higher revs. So, this leads me to look to the actual surface area that the air will travel through.

If we could wind tunnel the filter, I'd expect that there was a sudden differential at the filter as air bangs into it, finds a way through it, then gets back to intake speed. This is why I think a filter with huge area is important, and like I said in my original post, is the major reason **why the stock intake is restrictive**. At least that's my guess.

3b. Without the Intake, header, or exhaust (not just the muffler), there won't be much of a hp difference. The stock header and exhaust piping + muffler are very restrictive as well.

Right... more than the sum of its parts. Individually, they contribute little; together, you get a more than the sum of their individual contributions. But this is off topic.

You are at least thinking, and have good points to back your argument up, except the fact that the stock intake tubing is very restrictive and even muffles some of the sound. With an aftermarket intake you can actually hear something different.

Cliff notes: stock piping = ridges = restrictive, different material aftermarket intakes = smoother piping = less restrictive, different material = aluminum = conducts less heat, keeps air cool.

Actually, I prefer quiet.
As for the stock piping, its ribbed on the OUTSIDE, but inside, it's smooth... which is where it matters.

My question about aluminum is that because the under the hood temperature is higher than the "cold outside air", then the temp differential will cause the energy to try and creep the colder air. That means, you WANT the best heat insulator possible on your intake to keep it cold. So are you saying that aluminum is a better insulator than the rubber/plastic?

[B16EJ1]

Originally Posted by B16EJ1

WTF is going on here? I know you AF regulars have installed your own intake and yet no one has the exact answer yet. First off n00b no the OEM intake system is not a CAI. Yes, on a CAI the filter and actual induction does take place in front of the wheel but no your OEM intake does not. Try actually taking the OEM intake off and you'll see what I mean. The OEM does go into the front wheel well area but it induction does not take place there. Why because there is a RESONATOR BOX in there. From the RESONATOR BOX a pipe re-enters the engine bay where the actual air induction takes place. Hence, NOT A CAI. Stop being a cheap ass.

Did you not just read my post?

[Ricochet]

I want 5 min of my life back for reading this post.

[chimchim]

Originally Posted by B16EJ1

Did you not just read my post?

Actually, no I didn't. But I did now. I was replying but left my computer for awhile. Then came back to finish. Clicked post, and then saw you had posted something.

Why so hostile? Did I insult your mother or something?

Yes, on a CAI the filter and actual induction does take place in front of the wheel but no your OEM intake does not. Try actually taking the OEM intake off and you'll see what I mean. The OEM does go into the front wheel well area but it induction does not take place there.

So are you saying those CompTech Iceboxes and such are not CAI?

A CAI is not a CAI just because it sucks from the wheel and has a "smooth non turbulant path" all the way to the intake. Regardless of where the filter is, it just needs to have outside air going to it; wherever that comes from, whether it be the wheel, the cabin, the trunk, the roof, or wherever (although obviously many of those aren't practical or useful). If the stock intake brings air from the front wheel to the airbox, then that is a type of cold air. Granted, not as good as an engineered AEM CAI, but it's trying to utilize the same concept.

Stop being a cheap ass.

Well, smart ass, I'm not trying to save money, I'm trying to pick the right technology. I thought these boards were for discussion. So far I've just heard a lot of what you read on Performance Manufacturers ad campaigns.

[chimchim]

BTW, the whole thing that prompted this was (see original post) that I was wondering why (with all the "amazing" technology that goes into an after market CAI) it doesn't improve that much over the stock... even as very restrictive the stock intake is.

If adding a CAI, 421 ex header, and straight through cat back only adds less than 5% HP over the stock setup... then that tells me that the STOCK SETUP ISN'T THAT MUCH WORSE THAN THE AFTERMARKET "HIGHTECH" STUFF, unlike 30 years ago. And if the diminishing returns are expensive, then you gotta choose the right thing.

Not long ago people used to rave about ram air intakes like they are about CAIs.

[Ricochet]

It's just air coming into your engine, did you expect 300hp from a diff shaped pipe? i/h/e combos aren't great at adding (freeing up) horsepower, but they flatten out your stock, bumpy hp/tq curve lines making your hp now more efficient. Go get your car dynoed stock, then with all three i/h/e, and you'll see what I mean.

[B16EJ1]

Originally Posted by chimchim

Actually, no I didn't. But I did now. I was replying but left my computer for awhile. Then came back to finish. Clicked post, and then saw you had posted something.

Why so hostile? Did I insult your mother or something?



So are you saying those CompTech Iceboxes and such are not CAI?

A CAI is not a CAI just because it sucks from the wheel and has a "smooth non turbulant path" all the way to the intake. Regardless of where the filter is, it just needs to have outside air going to it; wherever that comes from, whether it be the wheel, the cabin, the trunk, the roof, or wherever (although obviously many of those aren't practical or useful). If the stock intake brings air from the front wheel to the airbox, then that is a type of cold air. Granted, not as good as an engineered AEM CAI, but it's trying to utilize the same concept.


Well, smart ass, I'm not trying to save money, I'm trying to pick the right technology. I thought these boards were for discussion. So far I've just heard a lot of what you read on Performance Manufacturers ad campaigns.

You are such a fool. The comptech intake removes the resonator and induction takes place where the resonator resides hence cold air seeing as it sucks air cool air from outside the engine bay. If you read my post I clearly stated that the induction point of an OEM intake is in the engine bay meaning hot air NOT cold. The reason for my so called hostility is because of how technical you try to come off when you clearly state......

Originally Posted by chimchim

The stock intake on my 97 Civic EX already is a cold air intake.

Well that's what it looks like to me. The only difference I see between the stock and aftermarket CAI's is the surface area of the filter. So, this leads me to believe that the "small, almost insignificant gains from a CAI" is because the stock intake actually shares almost everything in common with the aftermarket CAI's.

You base everything off of plain observation and not a good one at that. Everyone reading this with at least some mechanical understanding will see that my 2 posts simply prove your amateur hypothesis completely wrong. I and anyone who has actually installed a CAI or even removed any type of OEM intake knows exactly what I am saying. Before posting assumtions on basic bolt-ons such as an intake and trying to come off as a the Nutty Professor of air induction, do your homework. Do you actually think that major companies such as AEM, Injen, Iceman, etc. would spend so much on re-inventing a simple OEM concept? Please.

[Miataracer]

it doesnt make much difference on our cars because there is not a lot of power to start with. don't kid yourself, 5% more power is not that bad. if you started with 300 hp you would gain 15, just a slightly different way to look at it

[kicker1_solo]

Originally Posted by B16EJ1

The OEM does go into the front wheel well area but it induction does not take place there. Why because there is a RESONATOR BOX in there. From the RESONATOR BOX a pipe re-enters the engine bay where the actual air induction takes place. Hence, NOT A CAI. Stop being a cheap ass.

This is the correct answer. And I don't know how you can say that there's barely a gain from a CAI, mine made an incredible gain. I could barely get it over 120 before, now I can easily push it past 135. I notice more top end over bottom end, but it still gives much more power than the OEM intake.

Originally Posted by esp

on a side note like 3100 some posts between us!!!

add 13,560 to that