DIY: Fresh Air Ducting for Stillen G3 Users

jtown82

you would see cooler temps and better air flow using one side to bring in air and rearranging the other side to let the air out. that will allow more unused "hot" air to escape and allow for more cooler air to come in. your current setup is very flawed when it comes to the properties of Air if your trying to bring in cooler air. your basically making both those ducts fight for the same volume that one would be better off doing by itself.

trust me. growing up around my grandfather who spent his entire life working on air conditioners and swamp coolers and 5893475987 other cooling devices. and me being brought along. 1 route in and 1 route out always net better performance than 2 routes in and nowhere to escape. in this instance nowhere to escape means those filters are stuck having to suck in in very turbulent air thats being mixed with old and new air.

make one duct specifically to give that air coming in somewhere to escape other than the filters somewhere underneath if possible pointing backwards which would create a vacuum in a perfect setup. this will allow better airflow to the filter, reduce recycled heat soaked air to mix with the fresh air coming in and also act as a natural suction to help bring in air.

think of the top of the line computer cases the best cooling involves a fan to bring air in and one to suck air out. or better yet Turbine engines in airliners. one set of blades is pulling air in. the other set is pushing it out. this is the best and most efficient use of air's natural physics when the systems in not a sealed enclosure.

just my 2 cents. and im not trying to be mr negative just trying to help out

efuseakay

Yeah, turbulence is definitely an issue, as well as in-out... Perhaps a one-side-in full bumper-length piece with two outlets right in front of the filters themselves, and an outlet somewhere out/underneath the passenger side...

Damn... someone could make a fortune if they put together a fancy looking kit with proven gains for the Stillen system! lol

370Zsteve

This is an excellent post! Perhaps one fang vent used for intake, and the other modded the same visually but not running duct-work....

I don't think you would need "exhaust ducting" to flush out turbulence, just one duct coming in and the air would flow over the filters and dissipate via normal airflow

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Armonster

I agree with you in a general sense, but I'm not sure it really applies in this situation. Computer cases are different because you are just trying to get air flow across a surface, rather than forcing the air inside something. Here, we are not trying to get air flow across the filters, but rather air flow INTO the filters (and into the radiator). Furthermore, unlike a computer case or air conditioner, the air forced up there already has a number of escape routes (the most obvious one being through the radiator) that it will naturally flow to because of the pressure differences. And wouldn't you want air to exit through your radiator rather than an exhaust tube?

If anything, I think routing both pipes up there would be better, because (1) it would (slightly) increase the air pressure that the intake experiences; probably not enough to even call it a "poor man's supercharger" or anything, but who knows, and (2) assuming the air has sufficient escape routes, which it probably does as explained earlier, two pipes would put more cool air up there, to be used by your air intakes or sucked out through the radiator.

Finally, the point about turbulent air is not really relevant here. Air flow goes from laminar to turbulent at very low speeds, so once you start driving over 5 or 10 MPH (just guessing here, it's probably much slower) all of the air circulating around and inside every inch of the car is already turbulent. Not to mention that ducting isn't even smooth enough to maintain a laminar flow of water at driving speeds, much less air.

In conclusion, I give this DIY a

wstar

I recently (a week or so ago?) completed my own similar setup. I used the parts from Modshack's original DIY (the fang flanges, mounted the same way, and the same hoses), but I did the hose routing basically like the pics in cotizi's top post here (around the sides), and brought the ends of my hoses up to where they're even with the backs of the Gen 3 filters. I used some long plastic zip-ties at the ends and a couple places along the middle to keep everything in place.

I monitor my temps (Ambient, Oil, Coolant, Intake) pretty religiously all the time. I have my cellphone docked in my cubby w/ the door removed, and run Torque on that to monitor the coolant/intake temps, among other things.

The simple summary of the IAT changes is this: at highway-ish speeds (60+) it makes only a tiny difference, and I doubt it's enough to make up for the aero losses opening up the fangs. However, at slower rolling speeds it's actually really effective.

Prior to hooking up the ducting, I was generally observing a +12-13F IAT (over Ambient*** reading) at highway cruising speeds, and ramping up pretty quickly at slower speeds (not uncommon to see +30 or more at speeds under 30-35mph, depending on weather and traffic). With the ducting the highway is about +9-12 now, but at lower speeds I'm never more than +20-25 worst case (e.g. 10mph in traffic for a while). In general the IATs drop off a lot faster now as I accelerate, and stay lower longer as I decelerate as well.

I assume the minimal difference at highway speeds is because at those airflow rates the default Stillen setup was already getting all the air it could use through the main front grill. At lower speeds though, the ducted fresh air displaces some of the radiant hot air we'd otherwise be drawing off the top side of the radiator.

My net take on it is that it's definitely worth it for city driving and the track. Especially in a track scenario on a hard corner, I imagine it could save you 10 more degrees on your IAT at the moment you're starting to accel out of the corner, which is when you really want it the most. On a highway road trip it probably just eats MPG via aero losses for tiny gains though. Be nice to find a way to plug them for a roadtrip, might not be that hard to figure out.

*** - Keep in mind that our Ambient temp sensor is pretty useless in the absolute sense: they get road dust, dirt, and fluids splashed on them, they're not terribly responsive, and their relationship to the true ambient temp (vs coolant/oil temps) varies with other changes in the airflow/heat configuration under the bumper (coolers, etc).

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Nismo221

I was thinking of doing something like this.

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