2009 Nissan 370Z Stillen Cold Air Intake - Modified Magazine

Description
Remember when bolting on an intake made an extra 5 hp on a Honda? We thought those days were gone as cars got smarter and more fickle. It took intake manufacturers some time to figure out how to get around this, but now we're seeing a new generation of highly engineered intakes that are really good at providing additional top-end flow, but more importantly getting newer, overly complex vehicles to make power everywhere.

As far as building overly electronically controlled cars, Nissan tops the list with its pervious- and current-generation Zs, as well as the ultra-brainy GT-R. Stillen, a long-time tuner of all things Nissan, has found the secret to making easy power without retuning the EMS. The company's new Generation 3 long tube intake for G37s and 370Zs is the pinnacle of its intake tuning technology. When we heard the 17.5-whp (or 20-22 bhp) gains they were claiming from a bolt-on intake, we had to call BS and see for ourselves.

According to Stillen, the new Gen 3 intake system uses longer tuned intake runner lengths and MAF sensor positioning to make the most of providing more flow as well as tricking the EMS to make more power when compared to its shorter (but easier to install) Gen 2 system. After more than 50 design iterations, which were all extensively dyno tested, the Stillen engineers came up with the final Gen 3 design with optimized tubing lengths, diameters, minimal turns and the best placement for maximum flow and minimal intake temperatures. The kit replaces the two factory airboxes with dual-segment, polished-aluminum tubing that extends the intakes through the front clip so that the two K&N cone filters are placed just in front of the radiator above the main radiator duct. This also helps the intakes generate a ram air effect at speed. The kit also comes with additional PCV tubing, hose connectors and high-quality hose and T-bolt clamps.

Specifications & Details
'09 Nissan 370z
Sport Package
Engine:
3.7-liter VQ37VHR

Relevant modifications:
Stock

Key Features
Long tube intake runner design for colder intake temps
Dual independent cone filters
Polished aluminum dual section runners
15+ whp gains and increased top-end flow

Results
At 273 whp, piping hot on a Dynojet 248C dynamometer, the 370Z is no slouch out of the box, but it's temperature sensitive. Cooling it down sufficiently and supplying enough airflow will spike the output another 12 whp to 285 peak horsepower. We thought the Stillen intake would be in for some trouble, but after going through the trouble of pulling off the front bumper to install the kit, we saw a big difference.

The secret to these gains is mostly in the MAF meter placement, as designed by Stillen, and the overall reduction of flow restriction in the two massive K&N filters. While the power profile is still fairly similar all the way up to 6500 rpm, the A/F ratio is on average one point leaner than stock from 2000 rpm to fuel cut at 8000 rpm. The leaner A/F with the Stillen intakes allow the car to make more power since the car runs at WOT at a more ideal, but safe A/F of about 12.5:1 compared to the pig rich stock ratio of 11.5:1. Past 6500 rpm, the added flow of the filters allow the engine to keep sucking all the way up to fuel cut, whereas the stock airboxes start choking off. The best part is that CARB approval is pending, so soon you'll have simple effective power without worries from The Man.

Gains Made
+ 16.2 hp
+ 5.9 torque

Before
284.8 whp and 234.4 ft-lbs
After
301.0 whp and 240.3 ft-lbs