DIY: Fresh Air Ducting for Stillen G3 Users
 

I know this has already been covered, but after reading Modshack's post on the DIY: Fang air vents, I decided to see if I could devise some alternate routing for us Stillen G3 folks who don't use the stock air box locations.

With the G3 intakes the area in front of the filters is basically a dead plenum, as cold air for the engine is essentially stolen from the radiator and serving the filters from behind. Ideally, cutting holes in the front fascia (think Mines' setup) allows the most direct airflow to the air filters when using a Stillen G3 setup. However for people not 100% comfortable with buying inserts, or cutting their fascia, ducting utilizing the stock block off access areas in the fascia makes the most sense.
Best of all, this mod cost me $10. I simply purchased 8' of some 4" round flex duct(designed for dryers really) from Home Depot /Lowe's. I also used some zip-ties to secure it to the intake system itself.

http://i768.photobucket.com/albums/x...i/_MG_7894.jpg

http://i768.photobucket.com/albums/x...i/_MG_7901.jpg

As you can see the ducting path is rather straightforward. You can use any duct really, just avoid things that rust, or choke the airflow too much. Something closer to 3" in diameter would fit the cavity behind the front fascia better, but the lowest standard size I could find off the shelf is 4". The plastic dividers that separate the intake area for the radiator from the areas to the left and right ( washer fluid tank, etc) are easily removed. (sorry forgot to take a pic)

http://i768.photobucket.com/albums/x...i/_MG_7904.jpg

To attach the duct to the fascia, I utilized the stock screws previously used to secure the block off plates. The duct fits almost perfectly over the entire hole in the fascia where the block off plate used to be.

http://i768.photobucket.com/albums/x...i/_MG_7906.jpg
Finally you can see the entire pathing from the side. I suggest giving yourself some slack for when you need to take the fascia off in the future.


Performance results: Honestly this is more of a cheap, fun weekend project that costed almost nothing. As far as gains go, the G3 system is more efficient that stock, but I imagine that during high loads and long operating periods, the heat soaked bay will see some benefit from a more direct intake path, especially coupled with insulation wrapped intake tubing . Unfortunately I can't present any hard data at this point, as I don't have a reliable way to measure IAT's at this time. However, for the price it can't really hurt.

Worth noting, during install I took the air compressor nozzle and stood back about 10 feet and shot some air towards the intake ports on the fender, and you can definitely feel the airflow going through the duct effectively! It even looks kinda cool in my opinion, especially when you can tell people you have functional air ducts :).It actually makes a bit of a wooshing sound under WOT (caused by duct resonation) , but you won't hear anything if you dont have stock exhaust.

http://i768.photobucket.com/albums/x...i/_MG_7909.jpg

I'm also working on a solution that effectively rams air up to the filters from the main intake grille, but it requires cutting portions of the Styrofoam absorption barrier, which i didn't feel like doing for this DIY.

haha, i was thinking something along what u did too

awesome write up! I would spray paint the insides of the duct with a flat black though, so they can't be seen, but thats just me.

yeah, i think i will when i black out the fangs. :)

i was thinking of doing something like too :) but maybe with a little twist

nice ;)

Any noise or vibration?

Does the radiator actually suck in air? I thought it was just a pass-through. That said, as the intakes actually suck in air, they should still be able to suck in good fresh air once the car gets moving. Right?

BTW - GREAT thinking. I love the plumbing path you took.... I wish a full kit that includes the routing of air from the fangs would be released.

STILLEN: Gen 3 Take 2!!

Not with any kind of aftermarket exhaust. With stock exhaust there is a slight wooshing sound that wasn't there before, which is barely noticeable and gets drowned out easily with road noise.

I'm currently using stock exhaust with the muffler removed and turn-down tips installed and its loud enough to easily cover up any noise produced.

Right, the idea is to try and force high pressure ambient air into the side of the filters facing the fascia with the goal of reducing intake air temperatures. The faster your going the more "cold" air will be redirected into the area in front of the intakes!

I'm hoping once I get a complete exhaust system installed, I can really see what difference this solution makes, but with such a bottle necked exhaust its hard to tell. Maybe when its not always 100 degrees outside :(

O.K. So while a Stillen unit will help to suck in good cold air, your design will simply force even more fresh air to the intakes. Stillen = good, your design evolves the concept. Got it... :tup:

Well done man...

[QUOTE=

Well done man...[/QUOTE]

Have you tried logging intake temps to see if it makes a difference? Adding an oil cooler and will probably give your mod an attempt when it arrives. Good thinking.

Wrapped the Gen 3 intake tubes with 2 layers of insulated heat barrier and have been logging intake temps. After findout out the intake sensor was located with the passengers side MAF, I put an additional two layers around it this morning. Think that really did help.

Will do your mod probably next weekend. Thanks!!

Ok so could you explain to me why this might show better gains with a complete aftermarket exhaust as opposed to stock?

When you say the stock exhaust is a bottleneck are you referring to restricted airflow? So with the restricted airflow from the exhaust any gains in cooler air from the intake would be negated? If that's the case I don't understand why really. I would think the cooler air going into the engine would be independent of the restricted airflow of the stock exhaust and you'd see just as much power gains with cooler air regardless of stock/aftermarket exhaust.
I'm a complete newb so sorry if this sounds like a dumb question. Just trying to understand.

Think of it this way. The power plant (engine) system can basically be modeled as whatever goes in must come out. (Mass isn't destroyed, its properties are just rearranged during combustion). So if you take that approach, the exhaust can only eject so much gas at a certain pressure. The stock exhaust is limited by physical parts dimensions and flow characteristics, not by the power production of the motor. If you agree with this, then its fair to say the intake system will only suck in as much air as it needs to satisfy its combustion requirements. It cant suck in all this "extra" cold air if there's no where it can go. The best that could happen is to decrease the temperature of air that actually IS going into the motor to be as close to ambient temperatures as possible.

If the whole point of modding is the get colder/denser air into the engine so that more fuel can be injected to create more power, it makes sense that to FULLY utilize the gains of air ducting, it helps to have more mods. With full exhaust mods, not only is colder air going into the motor (because of ducting and G3 intakes) but MORE of it is.



Technical reasoning aside, ducting isn't exactly a huge HP adder, I got bored and decided it would be fun to do. This weekend I'm gonna paint it all black! yay.

Thanks for the reply cotizi. :tup: So what I'm getting from you is basically I have to start saving for an exhaust before the full potential of the G3 intakes are realized. I had originally thought the intakes were the bottleneck, not so much the exhaust when referring to stock parts.

simple effective FAD G3
 

Kept it simple - black pvc 4"-3" reducers and 3 " alum adjustable elbows. Removed entire fang blank off cover - trimmed up 4" PVC reducer to fit onto back of fang, mounted with same bolt as cover, shortened up 3" alum elbow to clear front bumper structure when installed painted elbow black-went back on car easy - can reach in from below to direct alum elbow in any direction- I pointed up to G3 filters- or you could duct to brakes if wanted- took about 2 hours total and $8. Put alum screen in front to keep out leaves and stuff. seems to work great no noise, whistle or any noise at any speed

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

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

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

Yup, or use the other duct for brake cooling, if you track your car...

Since my original install added the Stillen street oil cooler so I had to remove the elbow on that side and that fang now just dumps in straight just to the left of the cooler- I left the other elbow on and directed up towards the G3 intake- I agree with the turbulance comment but is seems to be working just fine- I do track the Z and have not seen any negative with cooling or air not getting where it needs efficiently- havin lots-o-fun

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 :tup:

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).

I was thinking of doing something like this.

Stillen's front bumper has an opening just for their Gen III intakes

Is there an update on this thread?

Has anybody done this? Wrapped the G3's?:pics:

I've actually removed my air ducting to rework a brake ducting system. At the time i wrote this DIY my car was a DD, but now its a dedicated track car. Need more brake cooling!

Did wrapping the tubes help you any?

kind of a dead thread but Id be very interested to see what you came up with for your brake ducting Cotizi. I did one track day recently on stock brakes... not good.

Edit: I do have new 2piece front and 1 piece rear slotted DBS rotors, Endless pads and fluid, and SS lines on the way but were delayed until after the track day.

Nice write up and another way to get air into our gen3

NICE i am going to try this on my G37

Just did this finally! Thanks for the write up :tup: it was tough getting the bumper back on with the big oil cooler lines and the ducting on the passenger side but if you push hard enough, anything will fit lol. I'll report on intake air temps, I've been watching them without the ducting so I'm interested to see if the difference is major.

UPDATE:

After going for a cruise and monitoring the new intake air temps, I can confidently say that the ducting for the G3's does work. It is 18 degrees Celcius here today, and after everything was warmed up (oil at 90 degrees, coolant at 83) while idling the intake air temp was around 38-40 degrees Celcius. As soon as I started driving again I could watch it dropping to around 27 degrees, and once moving faster 23 degrees Celcius. That's about where it stayed with Highway driving, 4-5 degrees C hotter than the ambient air temp.
This is a reduction of about 5 degrees from before I had the ducts. (I would see about 28C as the low temp on the hwy given the same ambient temperature) It'll be interesting to see come next summer how close to ambient air temp the IAT stays as I used to see intake temps of 58C when it was 28C outside

Just curious, does anyone run, or have thought about running the Varis or Mines air ducts, for this purpose?
Varis
http://www.hirano-tire.co.jp/vari2-2/front1.jpg
Mines
http://www.mines-wave.com/JP/CATALOG...Front_1000.jpg

I think they would work and be helpful for getting more/colder air to the G3's. The tradeoff is they'll also dump driving rain into your G3's (if you drive in the rain on the street). That and they're kind of expensive for little plastic edge-pieces. It would be cheaper to fab up your own or buy something generic that has the same basic shape.

Also, both of them as installed in the pics above are too far apart. Even the narrower Varis layout would be at the rear edges of the cones. It would help, but it would be more ideal to have the inlets closer to the center.

My friend (no longer on this forum) did that with some off brand ducts, he offset them so rain wouldn't hit the filters. Honestly, I think it looks REALLY bad...

Sorry... Um... I forgot the member that I think has these on his car, lol

do those 2 black pieces (where you put those pipe ducts) screwed on or clipped to the bumper or do I have to cut it out?

I’m gonna post on this old thread & see how others have introduced more air to their CAI’s.
Here’s my air guide I built to direct it through radiator & wraps around to filters....currently all foam is in place;but thinking of removing section in front of filters or either piping in from fangs.
Fangs currently blocked off.https://uploads.tapatalk-cdn.com/201...f752637f04.jpghttps://uploads.tapatalk-cdn.com/201...7f8c0a1a0c.jpg


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