Residual heat from asphalt is 20 degrees hotter than inside the engine bay?!? Am I reading that wrong? The only other way you could have air cooler than a CAI would be if you had an air scoop on your hood, so I don't quite get that explaination. Am I confusing something?

But I'm not going to go any farther...you made me bite my lip. Apparently this has been a debate all G35 users have had at one point or another.

Read this link, should hopefully give some insight on this.

https://g35driver.com/forums/showthr...ighlight=daveo

 

The G has a center duct that draws air directly from the grill – if you us OEM airbox or Stillen heat shield you are not sucking in engine compartment heat. You are drawing in outside air just like a long ram… however, it is much higher from the ground than most long rams… you are drawing in colder air…and IMO more air is drawn from the upper grill than lower openings in a bumper so there’s more of a ram effect… the 20 degrees is based on a hot day – clearly in the winter it’s not going to be 20 degrees hotter on the ground, but then of course you have water to contend with (depending on where you live).

Personally I don’t care what intake anyone uses… if you like the way it looks and don’t care about the negatives – go for it.

 

Yes, intake tube length has a very significant impact on the way power is made and the breathing abilities of an engine. Adding an extra 12" to 18" of intake runner length WILL impact the 1/4 mile performance of a VQ motor for the worse. I've personnally witnessed it myself with my old VQ30. On back to back runs, my modded VQ30 Maxima was .2 second and 1.5 mph slower with a CAI as compared to a modified stock airbox. Around town, though, the CAI felt more powerful. How could it be that an intake that feels more powerful actually be slower on the track? Here's why.

Long runners on the intake tract and also the intake runners of the manifold will create excellent low to mid range performance because columns of air stack up in the runner offering great laminar flow and immediate air delivery upon throttle application. However, as the rpms increase, the long runner design begins to create turbulence and becomes a bottle neck because the air cannot move fast enough to meet the demands of the motor. This leads us to the advantages/disadvantages of the short intake runners. Short runners basically behave the exact opposite of the long runners. Short runners cause turbulence at low rpms which hurts power and throttle response. This is why many report that their car has a "soft" lowend after adding certain POP-style intakes. As the rpms increase, the flow in the short runner matches the demands of the motor and all is well.

Many engines use variable intake manifolds which use butterfly valves to switch between two seperate sets of intake runners, long and short or the valves are used to open up a chamber in the intake manifold that makes a long runner behave like a short runner. The intake manifolds on the 00-01 Maxima, 02+ Maxima/Altima, and QR25 (Sentra/Altima) use variable intake manifolds. Some motors like that on the last Celica GTS and current Lotus Elise use variable airboxes to change the flow characteristics of the airbox at low rpms and high rpms.

In the end, the trick is to match the intake runner design to the car's needs. Truck engines are tuned for low to midrange power and cars are typically tuned for more mid to high power. Use of variable cam timing and lift along with variable intake manifolds has led to motors that can deliver excellent power across the entire rev range. We're living in a great automotive age.

The intake manifold on the 1st gen G35/350Z is a work of art. It can achieve 110% volumetric effiencency and it has no moving parts. It basically behaves like a variable intake manifold.

Finally, so the answer is yes, intake tube length DOES impact the way your VQ will perform. Adding a CAI like that from AEM, Injen, etc. WILL negatively impact the perfomance of your VQ. I can guarantee you that. OCG35 and DaveO are spot about this. The stock intake is already a CAI and it pulls air from the grill, not near the street surface. If BMWs M-division and Benz's AMG division believe that pulling air from the grill area is ideal, then why second guess what Nissan did with thier design? Same goes for intake tract length.

If you must have an intake, get the Stillen CAI. It's the best aftermarket design on the market. Too bad they didn't take it one step further and make the entire airbox enclosed to shield the filter from all under hood air.