DIY: Fresh Air Ducting for Stillen G3 Users

[cotizi]

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.





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)



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.


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.



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.

[g96818]

haha, i was thinking something along what u did too

[Mike]

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.

[cotizi]

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

[iceman21_23]

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

[dainedazz]

nice

[FuszNissan]

Any noise or vibration?

[Endgame]

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!!

[cotizi]

Originally Posted by FuszNissan

Any noise or vibration?

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.

[cotizi]

Originally Posted by Endgame

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!!

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

[Endgame]

Originally Posted by cotizi

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...

Well done man...

[Denny McLain]

[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!!

[Timmer1978]

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.

Originally Posted by cotizi

......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

[cotizi]

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.

[Timmer1978]

Thanks for the reply cotizi. 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.