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Discussion Starter #1
Disclaimer: The inventor (phamgiaj) of this "mod" gives no guarantees that installing this will result in increased 0-60 and 1/4 mile times. The inventor also has abstained from doing, and hence publishing, any Gtech results. He feels it is better to leave it to other members of the general infinitifx.org community to install their own version of this mod and make their own conclusions (be it Gtech times, track times, butt-dyno results, whatever). This mod is just a working prototype so any constructive ideas will be appreciated. :)

GeoFX, aka "sounding board" and marketing director. :p


The Concept: There is a little 1.5" diameter hole on the bottom of the fender well on the driver's side (actually a matched "hole" on the passenger's side too). The idea is to somehow draw cold dense air (close to the ground) through that hole and into the stock airbox via use of a "scoop" and tube that connects the hole to the intake. We use the stock airbox because it's basically a sealed box with a panel filter (thought about using a Stillen but it's open at the bottom). Doing this will give us another source of cold air in addition to the stock sources. In addition, this should be a more "direct" source of air too as it is blowing directly into the air filter.

The Execution:

1. Attaching a 8" wide vacuum floor nozzle at the bottom of the vehicle right below the "hole." The nozzle is held to the vehicle via use of an external bracket.
2. After removing the resonator attached to the bottom of the stock airbox, attach a ~14.5" long (1.75" OD at "nozzle" end and 1.5" OD at the "intake" end) commerical-use plastic vacuum tube attachment that connects the hole to the bottom of the stock airbox. At the hole end, the scoop and tube is held to the vehicle via a bracket. The tube should fit through the hole at the bottom of the stock airbox.

Notes: Use stainless steel mounting hardware. Parts shouldn't run more than $20.

Here are the pics:
 

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up periscope! :shock: couldn't resist - very ingenious, you guys let on the loose too long can be dangerous, even habit forming. :) Thought provoking, seems very logical. I/we applaud your creativity! ShadyJC, I think you left you FX with the wrong people. What do you think Duy? ...Duy?
 

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I have some leaves that need to be sucked up. Bring your FX by! :D

Actually looks interesting in a MacGuyver sort of way.
 

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Discussion Starter #7
An issue we have is whether there is enough pressure to "ram" cold air vertically up the vacuum tube. At what speeds is there significant airflow? Don't really know. Any physicists out there to help out?
 

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put a screen or mesh over the opening and it would stop most "large" items from being "hoovered" up in the intake.
 

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"Attention all K-mart shoppers, all of our 8" shop vac floor nozzles have been sold out!" :lol:
 

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Can't prove the mod w/o testing it, man. Are there at least any butt dyno impressions compared to stock?

The problem I see with it is the small diameter of the tube. It might provide a bit more air up there, but with three inlets, there's no chance for a ram air effect. I'd think alot more air would be sucked up with something bigger. The idea I've kicked around before (think some others have as well in one form or another) would be to run a larger, flexible duct from the side of the intake box where the center scoop connects to a larger scoop (possible the center scoop itself, located to another position. I took a look today, though, and can't see an easy place to run a duct from the box to a place where it would get fresh air (like in front of the radiator, behind the lower valence grill) and have minimal bends in the ducting. If there was a way to do this, you'd then want to seal up the "Power Duct" so the box is sealed except for the one "ram air" inlet and there's no other way for air to escape, thus pressurizing the box.
 

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Not a physicist but there are three inlets that are pushing air into the intake box (power duct, side and bottom) which would tell me that the inside of the air box would have a positive pressure at highway speeds when not stepping on the gas at a minimum – not sure at what rpm and speed there would be a negative pressure inside the box but it has to be at lower speed and high rpm. Since there are three inlets blowing air into the box it is going to take pressure to push the extra air that is not consumed by the engine out of the least resisting inlet, thus creating positive pressure inside the box equal to the amount needed to reverse/leak outward an inlet. Admittedly, probably not much pressure.

Since it is improving the positive pressure then it also means that it is minimizing the negative pressure inside the box when that is the case (at wot) thus making it easier for the engine to breath – using less energy to draw air in.

Not saying this is optimum or not but I think it helps feed the engine more air at the cost of higher risk of sucking in water/derbies and hot vapor being low to the ground. A screen might be in order. Then again, I could be totally wrong.

Nice job.
 

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put a screen or mesh over the opening and it would stop most "large" items from being "hoovered" up in the intake.
I highly doubt there is anough suction to even suck up a leaf
 

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first off.....very inventive guys :) .... i always said that hole in the bottom might be useful :D

this is an interesting concept. i have seen a BUNCH of 350Z guys buy custom fiberglass ram air slots that fit thru the bumper and they are basically the same concept.

as far as a "sealed" box, im not sure about the benefits with the pressure thing described above, BUT....those of us with JWT or Stillen CAI, i would think this can only help get cool air in there (since the CAI is not a full box...or a box at all with JWT).

in fact, those of us with JWT might get some good benefit fromt this since there is no provision for the OEM mini ram air scoop to be placed on the top of the CAI like in the Stillen.

definately put a mesh grille in that thing though (just to keep crap out of the engine bay)

in all reality too, you could bore out the 1.5 " hole to be 3" or so (if you have to room...cant remember). i see no other purpose for the hole other than drainage and maybe access from the bottom.
 

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:D :D What an effort Geo!

I think this is an excellent starting point of making a custom CAI. Good job Geo.
 

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Discussion Starter #15
topguy said:
:D :D What an effort Geo!
Actually phamgiaj was the one who designed the mod. i'm just his sounding board to bounce ideas off of. :p Full credit should go to him. :)
 

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GeoFX said:
topguy said:
:D :D What an effort Geo!
Actually phamgiaj was the one who designed the mod. i'm just his sounding board to bounce ideas off of. :p Full credit should go to him. :)
Sorry phamgiaj. At least you have a good marketer for your invention. :lol:
 

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definately put a mesh grille in that thing though (just to keep crap out of the engine bay)
where would the crap go? The tube leads into a sealed air box.

These types on intakes have been made before with good success. The tube though seems a little too narrow.

 

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You'll note in the pic above, though, that there is only one inlet. I still think that if the air pressure inside the box is greater than that needed for the intake flow, the excess air is going to be pushed out one of the other inlets instead of forcing it into the engine (path of least resistance). For true ram air, a single inlet is best. I realize that this set-up isn't neccessarily trying to create a ram-type intake, though.

First thing I'd try to do is a simple flow test. see if a ping pong ball will fit in the tube (of some other small, very light object), insert it in the scoop (and cover with a screen so it doesn't fall out), then go for a drive. Once finished, open the airbox (or check the scoop) and see if the ball was sucked (or blown) up into the box enclosure (no worries, the hole opens into the encloser in front of the filer panel, so nothing can get sucked into the engine). If it did end up in the box, at least you know you've got decent airflow going into it and that can't hurt.

I also wouldn't worry about water. Even if you drove through standing water and submerged the scoop, it'd take a lot for water to get pushed all the way up it and into the airbox (though I still wouldn't want to try it). The water, at any rate will not be sucked up the tube; that inlet will just be blocked and the other two inlets will provide all the air. Still wouldn't be a bad idea to put a screen over it, though, to keep out debris.
 

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MustGoFastR said:
I also wouldn't worry about water. Even if you drove through standing water and submerged the scoop, it'd take a lot for water to get pushed all the way up it and into the airbox (though I still wouldn't want to try it). The water, at any rate will not be sucked up the tube; that inlet will just be blocked and the other two inlets will provide all the air. Still wouldn't be a bad idea to put a screen over it, though, to keep out debris.
Totally true when the bottom inlet is submerged in water and the car is stopped or moving very slowly (again, path of least resistance), but one of the worries is when on the highway and small droplets of water and debris kicked around from other cars are getting carried in with the air inhaled or when the bottom intake is submerged and the car is going faster where the speed of the car would push the water up the intake.

The three inlets are facing the front of the car to one degree or another so the total surface area of the inlets are adding to pressurize the inbox.

Totally agree that some sort of a flow test would be very helpful.
 

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IssaFX said:
Totally true when the bottom inlet is submerged in water (again, path of least resistance), but the worries are when on the highway and small droplets of water and derbies are getting carried in with the air inhaled.
Small droplets won't hurt anything. Lots of CAIs locate the filter in direct line w/ incoming splash and debris (such as Injen on 350Z). Only real risk from water is hydrolock from submerged intake.

The three inlets are facing the front of the car to one degree or another so the total surface area of the inlets is helping pressurize the inbox nearly equally and one or more of them would have to be over powered to become an outlet/inlet when there is access of air.
I think one inlet could be easily overcome and become an outlet, as the inlets are all located and sized differently. The Z guys have criticesed this design for a while. In my Stillen, it is quite evident by the area of the filter that gets dirty, that very different amounts of air enter each of the stock inlets. My filter gets filthy under the "Power Duct", but nothing at all on the side where the center scoop dumps in. Basically, IMO, it would be much easier for air to escape from one of the inlets than to be be forced into the engine as boost. Hard to tell, though, really.
 
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