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Discussion Starter #1
i've seen a lot of speculation on the forums with lots of misinformation. so i decided to make this thread dedicated to YOUR experiences and opinions with what YOU have made and how it has worked out.

please only leave constructive feedback to posters offered as an opinion, not fact.

here's my current setup:
Apex'i dual funnel filter
custom made aluminum short 90 bend
black silicone couplers



i also tried this setup out, but found it to heat soak easily, despite being on the "cold side" of the engine bay. had a noticeable drop in power across the whole powerband as well as losing throttle response.



so, back to my current setup... i see people posting about how you will lose torque all over the place with this short setup. from my experience, this has not been the case at all. in the case of a 1.6L, yes, you will lose a fair amount of low to midrange torque. however, the 1.8L has a variable intake manifold which is designed to maintain air velocity equally across the powerband. you won't see dips anywhere regardless of the length of the intake tubing on a 1.8L. this short setup offers a night and day difference in throttle response with a obvious power gain from 4k rpm to redline. in order to see these benefits, you need to disconnect your battery for appx. 30 seconds and touch the cables together while disconnected. this will reset your ECU allowing it to learn the new setup to account for changes in the AFR and the shorter distance of the MAF to the throttle.

again, I DO NOT recommend it for a 1.6L

as far as actually performing this mod, it is very simple. with a razorblade, cut back the conduit and wire loom housing the MAF connector. the connector and AIT sensor will reach the passenger side without cutting any wires whatsoever. i would also recommend buying a new length of hose (twice as long) for your coolant reservoir to mount it back near the firewall to give yourself plenty of room for your new filter.

feel free to post pics of your setup and experiences!
 

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enormous gay swords.
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After going through 5 different intake setups, talking to Keith at FM many times, and doing multiple IAT and acceleration tests, I can 100% say that your statement about not losing midrange tq is completely false. A shorter intake will, in fact, cause a minimal torque dip in the midrange. It is less noticeable than on the 1.6 because you're losing the same number but its a smaller amount percentage wise.

Also, you only notice it in actual hard driving situations. You wont notice it by driving straight and stepping on the gas. After many intake combos, I found that a true CAI is the superior choice but requires the most work. A coldside intake will still get hot engine bay air, it just wont heat soak as quickly. My old intake which ran straight across the engine bay and sat in a box behind the headlight was superior to a coldside intake in terms of power and IATs but it heat soaked faster.
 

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Discussion Starter #3
living in Arizona, heat is a major factor in designing an induction system. i have found that the lesser surface area of plumbing has reduced the mass of material capable of retaining heat. therefore, despite drawing in mostly engine bay air, the shorter system doesn't have the time to heat soak like it would with longer plumbing across the radiator to the exhaust side of the bay. in all my outings to the local canyon roads, this setup has worked the best for me. the dramatically quick throttle response makes a huge difference when exiting an apex. sure, there might be tiny unnoticeable dips in torque somewhere, but the throttle response and high rpm power certainly compensate for those potential drawbacks (which i have not seen). i am confident that a variable intake manifold will compensate for pre-throttle plumbing length in maintaining optimal cfm.

maybe this will shed some light on my reasoning..

http://en.wikipedia.org/wiki/Variable_length_intake_manifold
 

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I created a homemade intake that looked like the first pic in th OP's post. I felt that the throttle response greatly benefited and I felt (never dynoed though, so who knows) more power. When I would do track days, I also removed the headlight and made a box around the filter for a ram air effect. That was even more noticeable.

I made mine with rubber connectors, a PVC elbow, and a K&N cone filter that I had laying around. No pics-- that was in 2003.

Overall, I found this to be a very worthwhile and cheap mod.
 

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Discussion Starter #5
my choice of air filter might also be making a contribution to why i haven't experienced any drawbacks..

 

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enormous gay swords.
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Do you honestly believe that your stock N/A Miata flows enough air to be effected by an air filter? It doesn't. Let me guess...you found those on the apexi website? No actual dyno graphs posted of course

What do you mean by a variable intake manifold? Are you to the VVT on 01-05 motors? Or the VCIS thats inside the manifold? I'm confused.

Like I said, "spirited driving" is not going to show the flaws of your intake. I'm not trying to be rude but if you aren't going to listen, ill stop posting. Ive done tests and Keith and Jeremy both have dyno proof of what I'm saying. There is almost no flow to that area because its a high pressure zone.

I live in Florida and deal with very hot weather too. Maybe not as hot but ive seen 115* (heat index) days. Couple that with the fact that I actually race my car (autox, HPDE) and you have some very convincing tests. I'm just trying to share my info.

Edit: of course you aren't able to feel small losses of torque. I have a strut tower bar, torque damper, stiffer motor mounts, stiffer diff mounts and an upgraded suspension on my car so I can feel every slight change in torque.
 

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Discussion Starter #8
the point of this thread is to have people off their personal experiences, not speculation.

this second pic i posted was done independently, not by Apex'i.
an air filter with a velocity stack makes an obvious difference.
if you don't know what i'm talking about when i say variable intake manifold, then i see why you're so confused.
i don't care about "dyno" proof because it is measured by theory, not practice, as in actually driving the car.
a high pressure zone is beneficial for drawing air. behind the headlight is a higher pressure zone than the stock location of the air box.

AGAIN, please just post a pic of your intake and elaborate why you chose to do it. i don't need lessons on internet here-say. make a contribution, offer your opinion, and move on to the next thread. kthx :phillyb:
 

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Do you honestly believe that your stock N/A Miata flows enough air to be effected by an air filter? It doesn't. Let me guess...you found those on the apexi website? No actual dyno graphs posted of course

What do you mean by a variable intake manifold? Are you to the VVT on 01-05 motors? Or the VCIS thats inside the manifold? I'm confused.

Like I said, "spirited driving" is not going to show the flaws of your intake. I'm not trying to be rude but if you aren't going to listen, ill stop posting. Ive done tests and Keith and Jeremy both have dyno proof of what I'm saying. There is almost no flow to that area because its a high pressure zone.

I live in Florida and deal with very hot weather too. Maybe not as hot but ive seen 115* (heat index) days. Couple that with the fact that I actually race my car (autox, HPDE) and you have some very convincing tests. I'm just trying to share my info.

Edit: of course you aren't able to feel small losses of torque. I have a strut tower bar, torque damper, stiffer motor mounts, stiffer diff mounts and an upgraded suspension on my car so I can feel every slight change in torque.
you got beat up in school alot...didnt you..?:hello kitty: "nothing to see here folks...move along.."
 

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enormous gay swords.
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......I don't see how that has anything to do with my post...? If you implied some tone in my post well then it was just that: implied. If you guys care more for butt dynos than actual data acquired while racing and driving, fine lol.

This thread is full of fail already. So many wrong things said. High pressure areas are bad for intake since air moved from high to low....you want your intake in a low pressure spot like the area behind the driver headlight.

This is my intake. Its a true CAI that goes into the bumper. After tests of different intakes, this one cane out on top.



Edit: velocity stacks definitely help. I was referring to the materials of the filters. Filtration and and flow are inversely correlated. More filtration = less flow and vice versa. You seem to know what you're talking about. All I'm saying is cut a hole behind the passenger headlight and extend it into the bumper so you get closer to the stock intake length
 

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Discussion Starter #11
THANK YOU for contributing. do you have any pics of the hole you cut? aren't you worried about drawing water into the filter? I've lived in the butthole of America too (PCB, Ft. Walton) and the storms are intense. same thing here. freak storms and flash floods.
 

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enormous gay swords.
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Lol I was contributing my technical information prior to my picture.

Ive driven it in the rain and I'm not too worried. I do have holes drilled before the upward elbow so water will fall out before getting sucked up. Its too dense to be sucked upward. I run a stainless steel filter with a velocity stack inside it so I dont have to worry about clogging the filter. After 2000 miles with this filter, ive noticed no extra debris on the throttle body butterfly.

I don't have pics of the hole and I'm away from my car till Sunday :'( I cut in front of the wheel well, behind the headlight and to the left of the framerail. If you look on the drivers side, there is a factory hole. Look in the corresponding spot on the other side and you'll see the spot thats begging to be cut. I cut it to 3"
 

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Great Minds think alike!



 

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The cold side intake would work best on NBs and NCs for the simple fact the NA's pop up head lights take up a lot of room.

A heat shield and/or some sort of heat blanket over the header will help any heat soak issues. Stormin'normin wrapped his heat shield in high-temp baking foil and noticed a fairly significant decrease in temperature next to the stock air box. Sure aftermarket headers are good to look at, but without any provisions for a heat shield your bound to see a significant increase in under hood temps.
 

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I spoke to spitefulcheerio about performing this cut into my '99 NB. The headlight housing is rather large and takes up a lot of space where he was able to cut (he has an 01+ NB, so the headlights are smaller, and do not protrude as much into this area). Looking at Andrew6691's signature, the intake on his 99 is possible due to the 01+ front end conversion.
 

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i shaved some of my headlight as did my coworker Glen(he has a 99) with the same cold air intake

see pic
 

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^Yeah, but that's an 01+ headlight, right? I know they afford more space back there.
 

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Discussion Starter #19
I spoke to spitefulcheerio about performing this cut into my '99 NB. The headlight housing is rather large and takes up a lot of space where he was able to cut (he has an 01+ NB, so the headlights are smaller, and do not protrude as much into this area). Looking at Andrew6691's signature, the intake on his 99 is possible due to the 01+ front end conversion.
this explains a lot. definitely couldn't understand what the hell anyone was talking about, as far as drilling through. can't make it happen with 99' headlights.
 

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interesting thread. i am not interested in doing a cold air intake, but rather a cold side as the OP has done. first saw this idea in Quinn's build thread, he has a really nice setup made of parts from siliconeintakes.com but that apex filter looks great i may have to do that

i currently have a 99 sport with a racing beat intake. to be honest, my main reason for doing this is to reduce weight and place more of what's left in the front passenger side (driver front is always heaviest right?) i know it's a small amount, but it's a cheap mod and sounds like power will be a bonus.

although i do likes me more torque. i did appreciate the technical analysis done by spitefulcheerio
 
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