So I just installed my K&N high flow filters. If I am in first or second gear and rev up to a out ohhhh.. 3k rpm then let the rpms fall while driving, i hear an odd hissing/sucking sound. I can't tell if this is due to my PowerHouse Amuse exhaust or the K&Ns.

Any thoughts? SORRY to derail....

Sounds like the normal sound you get with the K&N (and probably other intake set ups as well). Personally, the improved sound (including those you describe Endgame) is the main reason to add better flowing filters.

COOL!! I like the sound, just wanted to make sure it was normal...

so wat's the verdict?

OEM vs HKS drop-ins vs K&N drop-ins?

im still on stocks... not very convinced HKS or K&N will make any difference...

I'm weary of K&N drop-ins because we have hot-wire MAF's and I've had 2 destroyed in my Evo due to an oiled filter.

I think a smooth intake tube + new filter will make roughly 10 WHP. I'll dyno it next month. The AFE filters are sounding pretty good, but HKS filtration is more than sufficient.

I like K&N for the re-usability, improved sound and improved air flow. I never over oil them. I've not tried some of the other solutions discussed here, though.

I have to say the the stock filters were better than most. And the intake system is well designed for a stock set up. Obviously, others have improved on it. But compared to most of the restrictive systems on other cars, the Z's is a breath of fresh air (that's an intake joke, by the way).

Sounds good. Keep us posted on your experiment.

Professordave- complete agree that the stock setup is pretty sufficient. I ran scanguage IAT and it was better than expected. As far as cool air its plenty good... I just want to improve the filters if there's room.

A slightly wider MAF section like what Modshack is doing will net you some gains. I think you will get a few HP from better flowing filters but not sure about smoothing out the intake tubes, I dont think the air gets too turbulent to begin with. But who knows.

Drop in filters won't do a whole lot when it comes to HP, they are designed to slightly improve airflow but the biggest benefit is that you can reuse them instead of buying a new oem every 10k miles

The only thing larger MAF housings on a car that already has 2 ~2.5" housings will gain is a leaner mixture. Without re-scaling your MAF within the ECU ROM, it's just going to lean out your mixture - which will net you some nice gains on the stock tune. Think about the surface area of 2 separate housings. That's massive to begin with - compare that to what has been accomplished with just one MAF and throttle body on the non-HR 350Z.

Even Evo guys are fine with the single ~2.75" MAF which is pre-turbo (non-compressed) until 600 WHP or so. After then, it causes a measurable restriction.

yah, this is where i keep ending up... i cant see myself spending extra over stock filters for a freer breathing filter that cant really translate any more than a few hp improvement. such small change (like 3-4whp) is like the difference between driving in a humid or dry morning.


anyone try with the ARC intake tube yet? :)

I've been using the HKS filters with Cobb tubes for a bit now. Sound is more pronounced, and response is much better than stock. No idea on any power numbers but it's a fair improvement for driveability. I'd be willing to try the AFE filters next after these wear down.