Sharper throttle response, new noises.
Anyone just getting started in the world of car modification can feel a bit overwhelmed. All the different parts, new terms, technical details - where do you even start? For those enthusiasts looking to eke out a little more power, a high-flow intake could be the perfect upgrade, offering not only more ponies, but some lovely added induction noise as well. With that in mind, Tuner Fan recently tackled a Stillen intake install for a 2007 Infiniti G35 four-door.
Why A Stillen Intake?
The car in question belongs to Alexis, who had already installed a new cat-back ARK Performance exhaust system. Alexis loved the way the ARK Performance exhaust gave the 3.5-liter V6 a throaty new tone, and the next logical step was to uncork the other side of the engine with a new high-flow intake system.
Given his 2007 Infiniti G35 shares the same dual-throttle-body VQ35 engine as the ever-popular Nissan 350Z, aftermarket support is plentiful, with tons of options to choose from in the aftermarket.
Alexis ended up ordering a Dual Ultra Long Tube Gen 3 Air Intake kit from Stillen. Full disclosure - Stillen did not sponsor this install or provide reimbursement of any kind. All parts and components were paid for out of pocket.
As Stillen states on its website, high demand has led to long waits between when parts are ordered and when they are received. After several weeks, Alexis finally had his Stillen intake ready to install.
The Dual Ultra Long Tube Gen 3 Air Intake kit replaces the stock components with mandrel-bent aluminum tubes that reroute the intake pickup point to the front of the vehicle, just ahead of the radiator and behind the grille. This means the air feeding the engine is dense and cool, thus maximizing power gains and engine response. According to the Stillen website, the Dual Ultra Long Tube Gen 3 Air Intake kit adds upwards of 14 horsepower and 8 pound-feet of torque at the wheels, all with that critical CARB exempt classification (E.O. # D-436-21).
What's more, the kit is relatively straightforward to install, and can be done in your driveway with simple hand tools. Which is exactly what we did.
Installing The Stillen Intake
Prior to starting the install, we laid out all the parts to make sure nothing was missing. The Stillen intake kit also includes step-by-step instructions, making things that much easier.
Given the install requires removal of the front bumper, we picked up a few bags of plastic bumper clips (Nissan part code 01553-2DR9A). The plastic clips can be brittle, and easily break when removed. Finally, we bought an inexpensive ($20) rotary tool from Harbor Freight to trim the plastic duct holes in order to fit the new pipes.
With everything prepped and ready to go, we started by disconnecting the negative battery cable (the battery is located in the upper passenger's side portion of the engine bay underneath a plastic cover), then removed the plastic engine cover. The engine cover is attached with five bolts.
Next, we unplugged the mass airflow sensors from both of the factory intake pipes by unclipping the wire from the sensor. These components will be reused with the new intake.
For the next step, we removed the factory plastic intake pipes by loosening the clamps around the throttle body and the clamps closer to the mass airflow sensors. We also removed the clamp around the breather tube connected to the upper portion of the factory intake, which required some pinching and wiggling to make it come loose. A single 10mm bolt securing the airbox to the fender was also removed. With all that done, the intake is removed by pulling it free from rubber grommet underneath the airbox.
Removal of the forward radiator cover is next. This step involves taking out a number of bolts placed along the top edge of the radiator cover and in the center of the cover near the hood latch, as well as plastic clips along the lower edge of the cover. This step also involves unclipping the hood latch cable and wire harness, the former of which can be accomplished with a flathead screw driver, and the latter of which can be accomplished with some some pliers. Getting to the hood latch cable and wire harness is a little awkward, so you may want to loosen up the radiator overflow tank to make a little extra room.
The next step is arguably the trickiest of the install - removing the front fascia. The Infiniti G35 has a large, one-piece fascia that includes the bumper and the grille. Removing this big hunk of polyurethane involves a plethora of plastic clips and bolts, including several underneath the fascia attached to the front leading edge of the plastic undercover, several underneath the rubber flaps in the outer corners of the fascia, and several inside the front wheel wells. There's also a few bolts located behind and underneath the headlights, connecting the fascia to the fenders.
Finding all this hardware is a bit a of a pain, so take your time and gently pull on the fascia to see where it's still attached as you go.
With the fascia finally removed, we pulled out the foam bumper support. No hardware for this piece - it pulls straight out.
The factory air ducts were the next pieces to pull out. These are held in place with a single bolt per side that connects the pieces to the core support, as well as some plastic clips. The plastic ducts took a little maneuvering to remove fully from the engine bay.
With the fascia and factory air ducts out of the way, it was time to break out the rotary tool. Taking a small grinding bit, we removed some of the material around the factory intake duct holes, frequently pulling out the new Stillen intake pipes to test for fitment. The Stillen lower pipes are installed through these ducts and wrap around to the front of the radiator, so we took our time to make sure there was plenty of room for clearance.
With some of the material removed, we then used sandpaper to smooth it out. Also note, if there's any rattling or vibration with the new pipes installed, more material may need to be removed from the duct holes.
It's also important to be wary of the AC lines around the driver's side duct hole - definitely don't want to hit those with the rotary tool! To help protect the lines from the new pipes, Stillen provides some 3/8-inch silicone hose, which wraps around the lines and is secured with zip ties.
With all that done, it was time to install the new Stillen intake. Note that all of the clamps should be fitted loosely at first in order to make it easier to adjust fitment as each section is added.
The pipes are installed in two sections per side, with an upper pipe fitted to the throttle body, and a lower pipe snaking through the larger duct holes, bending inwards towards the front of the radiator.
The upper pipe goes in first, fitting to the throttle body with the stepped hose coupler clamps and tapered silicone coupler hose. The breather tube connects to the breather nipple using the 5/8-inch silicone hose piece and is secured using two small clamps per side. One of the upper tubes includes an extra bend - this one goes on the passenger side of the engine bay. The straight couplers were then fitted to the other end of the upper tubes.
Next, the center bracket was secured to the center support bar in front of the radiator using hardware from the kit. This piece holds the two air filters in place. With the center bracket installed, the filters were fitted onto the elbow-shaped lower tubes. With the filters fitted to the lower tubes, the lower tubes were then installed through the air ducts and fitted to the upper tubes using the straight couplers. Be careful when fitting the lower tubes to the upper tubes, as it's easy to scratch the finish on the new pipes against the ducts.
With all that in place, the supplied splash guard was fitted to the longer filter bolt and secured in place with a locknut. This step was a bit difficult, as the space around the locknut was very tight, and required a lot of patience to get the locknut secure. However, the splashguard is critical, as it helps to reduce any incoming water that may make its way through the grille and into the filter.
To note, Stillen recommends installing the filter with the longer bolt on the passenger's side. However, we failed to catch this part of the instructions and installed it on the driver's side instead. We didn't see any clear reason why the longer bolt needed to be on the passenger side, so we left it as is. We'll report back if that was the wrong decision.
With the filters and tubes installed and properly adjusted, the clamps were tightened down. Next, we removed the mass airflow sensors from the factory intake using a Phillips screwdriver, then reinstalled the sensors in the upper tubes of the new Stillen intake. We then plugged in the sensors with the wiring unclipped earlier.
With all the new components in place, we reconnected the battery and started the engine to make sure nothing rattled. Everything sounded good, so we reinstalled the foam fascia support, the fascia, the radiator cover, and engine cover. These last steps were much easier than during uninstallation, given we were now familiar with where all the bolts and clips were located.
The Results
The first thing we noticed with the Stillen intake installed was a tasty new induction noise, which gave the V6 an awesome "whooshing" sound on throttle that complemented the upgraded cat-back exhaust system.
Alexis also reports that throttle response is noticeably sharper, and the engine now feels "healthier." We didn't put the car on a dyno to find out exactly how much power the Stillen intake makes, but Alexis says he's happy with the gains.
Perhaps most importantly, Alexis also says he's now more comfortable with modifying his car. Although the install process was a bit intimidating at first, he says it all clicked as soon as he started removing the factory components.
Up next, Alexis says he’s thinking about headers. Stay tuned.
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