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Discussion Starter · #1 ·
After reading several threads about cold air intake mods and how they don't really improve anything but the sound. And hearing from folks like Dev and Cap Weir that the stock setup is better than aftermarket intakes, I decided to take a closer look at my '02 stock intake.
It opens into the engine compartment just in front of the fuse box in the drivers side engine compartment. But what I found is that a large bundle of wiring is routed right in front of the intake. And the intake doesn't orient toward the air flow.
(This pic shows the bundle but after I'd already cut the tie-down. It was actually closer to the opening than it appears in this pic.).
I thought that clearing the wire bundle away from the opening would help increase air flow so I rerouted the bundles to remove any obstruction to the intake.

After doing this I started wondering if there might be a way to increase the air flow to the stock intake. The drivers side vent is partially blocked by the fuel tank filling tube, what looks like a vapor return pipe and another one I don't know. The air that does enter the engine compartment has to turn a corner to be sucked into the intake. Would re-routing some of that air coming in toward the intake help performance?
So I came up with this.

I cobbled together a small intake tube from 1 liter coke bottles to see if I could make a sort of ram air device that wouldn't constrict air flow at idle but would increase the air entering the intake when moving and at speed. More views.

And another.

And here it is installed into the side air vent.



And after the fuse box and battery were reinstalled.


I don't know if this mod will help, hurt, or have no affect, but I'll let ya'll know what happens.
I'd love to hear any thoughts on this and if anyone else has tried anything like this before.
If it does seem to have a positive effect I'll figure out a way to make a more,// er, ..durable version.
 

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wait a second, so all that piping and it ends up back in the engine bay?
 

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In my old (1ZZ ) set up where I used the stock air-box with an ITG panel filter, I had a 3 inches diam. rubber hose inserted (squeezed actually) in the left side vent and ducted the incoming draft straight to the above shown engine bay opening, just next to the electrical box. The straight portion of the 3 inches rubber hose was about 35-40 centimeters and in purpose to form the necessary curve to the opening I attached an aluminum flexible (of the same diameter) ventilation duct using - what else? - duct tape.
As for the results? Well, I cannot prove anything since I have no pre and after dyno numbers, but the feel was that in higher speeds there was "some" difference felt in my butt dyno.
 

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Interesting approach let us know if it works. Any way to smooth out the inside? be my only observation.
Could probably find a 45 or 90 degree bend of PVC pipe or Aluminium intercooler piping which you could cut to form a smilar shape which would be more smooth and be more durable also with a better finish now that you have the shape that you want worked out.
 

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I hadn't thought of that and its interesting. One thing to remember is that you cannot force air into the engine. The engine is like a lung, it will only gulp as much air as it can utilize. The best you can do is make sure there is the least amount of obstructions in the way of gulping air and that the air is as close to ambient as possible. Whether your idea will help or not, I am honestly not sure.

Here is a good summary of the entire stock intake system:
http://vps2940.inmotionhosting.com/~spyder5/forums/showthread.php?29804-Stock-Intake-Dissection

Some things I'd also look into for stock airbox modification:
-Removing the sound wall located inside the top half of the stock airbox, you can see it in one of the pictures.

-Insulating the stock airbox by putting insulation on the *inside* of the airbox.
Example:
http://www.s2ki.com/s2000/topic/780806-stock-airbox-mod-inquiry/page__st__25
 

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I applaud your effort however I have to be the Debby downer on this one and point out a few things.

1. The inlet of the tube in the fender is not facing the flow of air for a good reason. That reason is to avoid as much dust and contaminants in the direct flow of the air.

2. The intake is only concerned with drawing air though suction at a cold source only and when air enters the side vent which is cool it does not matter if it is in a direct or indirect path to receive the air just that the air is cold. Indirect path is better for reasons out lined in point number one.

3. The pressure gradient of air flow though the tube what ever that maybe will not be anywhere sufficient to increase any power what so ever.
 

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I hadn't thought of that and its interesting. One thing to remember is that you cannot force air into the engine. The engine is like a lung, it will only gulp as much air as it can utilize. The best you can do is make sure there is the least amount of obstructions in the way of gulping air and that the air is as close to ambient as possible. Whether your idea will help or not, I am honestly not sure.

Since when cant your force air into an engine? What do you think turbo does? ... and if your all like but you cant ram air in just from driving speed... then have a look at any current model high end sports bike. They have a ram air design intake which actually makes quite a large difference. If you look at the power figures in their brochure they have 1 power figure quoted as a dyno rating, and another which is at 100kmph or around there. Yes you do have to be going pretty fast for the ram effect to help but it does exist. In saying that what you have made will not achieve this. A ram system relies on the feed being sealed all the way to the engine.

I have seen a few "ram" air intakes aftermarket for other cars. I remember greddy made one for the swift. They had measured, and there was a noticable increase in boost pressure shown on the guage when at decent speed with the ram air compared to without it, something like 0.2 psi i think it was from memory.

The only reason its not on every sports car is that it would put alot more dirt and debris into the filter and ultimately the engine if theres poor filtration as mentioned which isnt so much of an issue on sports bikes.
 

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We aren't talking about turbos or sportsbikes...I am talking about the OP trying to force air into the intake tube by putting it into the path of oncoming airflow. I thought that was implied. Obviously a turbo does force air in and if you have an open intake inlet gong 100 mph into direct air resistance you will "force" air into it. But this is irrelevant to the discussion.
 

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@Levi: My friend, in my understanding no one here even hinted anything about ram air "forced" induction, not that it cannot be done, but there are other issues , including the expected gains vs the effort and expenses. All we are talking about here is a cheap DIY 5 minutes job in purpose to get lower than stock intake temperatures and the subsequent gains but with possible concerns as Dev said before!
@T-Bone:As for the internal (not existing) smoothness of the aluminum duct that I used, I think that the incoming air draft no matter how turbulent may be, will be smoothed out through the factory route up to the air-box.
And by the way, I must say that I had replaced the U shaped plastic tube located behind the left rear lights pod with an other tube (8 cm dia) in order to get rid of the venturi part of the original tube. As for the internals of the air-box I did nothing besides the filter panel replacement with one from ITG .
 

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Since when cant your force air into an engine? What do you think turbo does? ... and if your all like but you cant ram air in just from driving speed... then have a look at any current model high end sports bike. They have a ram air design intake which actually makes quite a large difference. If you look at the power figures in their brochure they have 1 power figure quoted as a dyno rating, and another which is at 100kmph or around there. Yes you do have to be going pretty fast for the ram effect to help but it does exist. In saying that what you have made will not achieve this. A ram system relies on the feed being sealed all the way to the engine.
I am glad you believe the advertising. Having built race bikes with "ram air" systems, I can attest they work - but there is a caveat. The ram air effect doesn't really have much effect until the speeds are significant, like well over 100 MPH. At 150+ on a race bike, ram air was reported to be worth maybe 5 hp. Considering the dollars spent to get even 1 HP, that was cheap HP.

But such systems have to be very carefully designed, or all you get is turbulance and kill the power. Unless you have access to a wind tunnel, your chances of success are pretty slim.

At highway speeds you would get more effect from the cooler air coming into the airbox.
 

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Discussion Starter · #13 · (Edited)
Please sir. I wanna hear your thoughs on how this mod works.
I was thinking that increasing the velosity of the air entering the stock intake, as well as reducing the amount of warm engine compartment air in the mix could/might bring some benefit to the combustion efficiency. But I didn't want to restrict the intake at idle. I tried a closed intake extension first but was worried that it might reduce the air intake at idle or slow speeds. I was just trying to put more air pressure at the opening when moving.
 

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Discussion Starter · #14 · (Edited)
Interesting approach let us know if it works. Any way to smooth out the inside? be my only observation.
As Ben 88 said, if this seems to have a possitive effect, I'll try something made from pvc. This was a cheap experiment I thought up and constructed from what materials were available at the time, (late night Saturday with too much time on my hands).
It was actually smoother untill I decided to paint it to make it more weather proof. The duct tape "puckered" after applying the paint.
 

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Discussion Starter · #15 ·
I applaud your effort however I have to be the Debby downer on this one and point out a few things.

1. The inlet of the tube in the fender is not facing the flow of air for a good reason. That reason is to avoid as much dust and contaminants in the direct flow of the air.

2. The intake is only concerned with drawing air though suction at a cold source only and when air enters the side vent which is cool it does not matter if it is in a direct or indirect path to receive the air just that the air is cold. Indirect path is better for reasons out lined in point number one.

3. The pressure gradient of air flow though the tube what ever that maybe will not be anywhere sufficient to increase any power what so ever.
Thanks for your appause. But 1.) as to dust, the difference in the amount of dust "ingested" from this mod v.s. the normal amount of dust entering the air vent would be nominal in my opinion. I mean, if the road is dusty, dust will enter.
And 2.) the pressure gradient? All I know is that when testing the mod I used an old hand held hair dryer pointed at the opening, and what I observed seemed to indicate that a significant amount of air flow was redirected to follow the curve of the tube. Which when installed pushes air directly into the intake opening. Does it make a difference? I don't know yet, but it has to be more air entering the intake tube than would happen in a passive suck situation.
My main worry was water getting sucked into the tube when it rains, ( a more and more rare occurence around here).
 

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Discussion Starter · #16 ·
I appreciate all of your comments and critiques. This is only a test! However, I will say that I took the spyder for a nice 120 mile round trip this afternoon with the mod in place and it seems that there was a deeper growl to the motor and I got to speed a little quicker. I think i need to run it this way for a while then remove it and see if I notice a loss of any performance gains that may be occurring before I can make any kind of sound judgment on the 'worthiness' of this mod.
 

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I am glad you believe the advertising. Having built race bikes with "ram air" systems, I can attest they work - but there is a caveat. The ram air effect doesn't really have much effect until the speeds are significant, like well over 100 MPH. At 150+ on a race bike, ram air was reported to be worth maybe 5 hp. Considering the dollars spent to get even 1 HP, that was cheap HP.

But such systems have to be very carefully designed, or all you get is turbulance and kill the power. Unless you have access to a wind tunnel, your chances of success are pretty slim.

At highway speeds you would get more effect from the cooler air coming into the airbox.
Are you saying that there is more to this, such as venturi effects and potentially creating a low pressure area in the tubing which will negate any effects at all? How dare you interject logic. /sarcasm


In other words, I'm with beachbum. There's more to it than just making a 'snorkel' to force air into your engine. You need to understand airflow, pressure drops, dynamic vs. static pressures, a law of Newton's or two and some other stuff I'm probably forgetting.
 

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I appreciate all of your comments and critiques. This is only a test!
I think its great what your doing regardless of whether it works or not. Testing is the best way to learn what works and what doesn't. We can theorize and speculate all we want, but doing it is the only way to find out for sure.

However, I will say that I took the spyder for a nice 120 mile round trip this afternoon with the mod in place and it seems that there was a deeper growl to the motor and I got to speed a little quicker. I think i need to run it this way for a while then remove it and see if I notice a loss of any performance gains that may be occurring before I can make any kind of sound judgment on the 'worthiness' of this mod.

I would add that investing in a OBD-II scanner or a OBD-II app for a smart phone would be a good idea. It's a great way to determine actual gains from reading the long term fuel trims, iat, etc. It adds a bit of hard data to compliment your observations,ear,butt dyno.
 

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Thanks for your appause. But 1.) as to dust, the difference in the amount of dust "ingested" from this mod v.s. the normal amount of dust entering the air vent would be nominal in my opinion. I mean, if the road is dusty, dust will enter.
And 2.) the pressure gradient? All I know is that when testing the mod I used an old hand held hair dryer pointed at the opening, and what I observed seemed to indicate that a significant amount of air flow was redirected to follow the curve of the tube. Which when installed pushes air directly into the intake opening. Does it make a difference? I don't know yet, but it has to be more air entering the intake tube than would happen in a passive suck situation.
My main worry was water getting sucked into the tube when it rains, ( a more and more rare occurence around here).
We can talk about this forever but it will not lead anywhere.
I am willing to donate $30 towards a dyno test to prove that there are no gains from this.
 
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