I'm seriously considering buying this combo package because all the modifications I've done on my car so far have been for exterior or interior looks, no performance parts yet . I've noticed that MANY people with the G35's use this combo of filter and z-tube but I am not yet sure as to what it really does for the car . How do the K&N Drop-In Filter and Z-Tube affect the G35? Performance, mileage, etc? Thanks for the info!

 

Performance wise expect to see minimal gains, maybe 2-5HP. I think most people have seen an increase of 1-2 MPG. For the most part people get it for the sound it produces above 4000RPM's
-GP-

 

As a stand-alone mod, the performance benefits are negligible at best. However, one may realize a greater performance benefit when the said combo is used in conjunction with a plenum spacer. Aside from a slight increase in intake noise and exhaust tone, don't expect very much.

 

I also feel that getting ones hands a little dirty and having fun adding something to the G is worth something too. Hard to put a value on it.

 

Word
What he said.

 

^+1

 

^+a million!

 

The K&N should be better than stock and is reusable. The ztube should add a little sound but not much else. It should be better than stock and work well with any future mods.

 

I didn't care for the K&N and Z-tube mod. The performance gain was minimal and so was the added sound. I paired the Stillen intake with the Z-tube and started to notice a difference. Sound and performance will be better if you use a cone filter like the Stillen or JWT. It depends what you are looking for.

 

Remove the "Power Duct" cover if you really want to hear the induction noise.

 

Have you done this? What exactly do you mean by "cover"?

 

It's that rubber gasketted thing that says "Power Duct" that sits at the front of your airbox.

I would think that leaving it on would give you a bit of a "Ram-Air" type effect, so I'd expect that other than the extra noise, there's not going to be much difference.

 

By removing the cover, won't that allow warm air from the engine compartment in?

I've got the Z-tube/K&N combo and like it - mild increase in sound. Logic dictates that a freer flowing intake and tube will get more air to the engine and therefore improve performance. However, dyno data has shown that the gains are minimal - coupla horsepower. Some of the other intake mods, Stillen and Injen CAIs for example, have dynos that show a loss of torque at lower RPMs, though HP improvements up top.

Whatever floats your boat really. I like the mod - it was my first, and a great easy way to get started. Of course, now I'm a mod-addict...so I guess you could consider it a "gateway mod".

 

I'd think you'd actually lose some power. Without that cover, wouldn't you now be pulling in some of the hot air from the engine? This might cause a minimal loss of power...but, yes, more noise. I'd either replace it (w/ JWT or Stillen) or leave it on.

 

I have the z tube and K&N and have a Techtom ODB plug in that lets me see the intake tempature. I've done a couple of informal tests with and without the "power duct" and find that while sitting idle, the no duct intake reads hotter by a few (10-20) degrees in the summer.

BUT when accelerating my intake temps drop radically to ambient +10 degrees unless the engine bay is heat soaked. Even when heat soaked, @ speeds > 55 mph, the intake temp is always moving toward the ambient +12 to 13 degrees and moving fast.

Note that my car also has the airbox drain or resonator removed and an open hole in it's place and feeding it is cool air moving into the lower bumper where I removed the foam inserts for my former Injen CAI.

Taking the power duct off sounds terrific and while it can add a few degrees to the intake temps of a city driven car, the loss is not noticable.