I want to replace the stock filter with something less restrictive but do not want to replace the stock airbox. From articles that I've read, the stock airbox in the G35 and 350Z is a great design (air ram, location, etc.) When I mentioned to a friend of mine who is very performance tech savvy (f-body and STi guru), that I was going to get a K&N, he said that I should should be wary of using any oil based filter with a MAF, like in our G or an STi. So I looked around and found that Nismo makes a dry high flow filter for the stock airbox. So does Greddy (Airinx II). The Nismo is expensive as heck for a disposable filter ($89) and I have no idea how well the Gredy performs ($39). I'm not just looking for high flow, but also engine protection. Anyone using either one of these filters care to chime in? Power? Sound? Longevity?

TIA

 

Thats interesting, I've never heard anyone mention anything like that before. I guess he's basically stating that oil from the filter could get on the MAF and damage it, however thats highly unlikely. Like I said I've never heard of anything like that happening (unless maybe you DIY with a recharger kit and put to much oil) but I don't think the K&N is oiled to the point where some could come off and get on the MAF. If you're somewhat wary of this though, go with the Greddy or HKS as far as the foam filters are concerned. The NISMO S-Tune filter is way over priced and I think its actually paper too.

This brings up yet another interesting concept. You mentioned the air ram, location, etc of the stock air intake system. I was talking to another member, DaveO, about this topic. He pointed out (which I had never really noticed before) that the functional air dam always stays clean. You never find bugs, dirt, or residue of any kind in it despite the fact that you will on the outer hood and grill surrounding. So that brings the question, is it really functional? It doesn't appear to be because it seems no air is getting to it and rather its just there for looks. Of course the rest of the intake system is functional in drawing from the tire well and what not, but as far as the "air dam" and "power duct," thats questionable.

 

Research on Fram's Airhog filters, they too are suppose to be less restrictive than a stock filter. Yes like Birdman said, a K&N filter should be fine, its not like you car is a high powered to take oil off the filter and have it land on your MAF. Thats highly unlikely.

 

well plus the fact that the K&N is sold at every infiniti dealer I have seen (3 while looking at car buy)

The oil is more likely to dry out from a dusty / dirty area

There shouldn't be anywhere near enough oil to get sucked off
As far as a MAF being damaged, given that almost all cars now have one.... I dount it

Also all of the pop chargers and such are oiled, and also sold at many / most dealers

As well the nismo CAI is oiled

 

In my past experience with nissan Maf's and K&N filters, when you do RE-oil the filter, its best to put as little oil back on it as possible or else you will get a clogged Maf...its happen to 2 of my cars in the past. the sensor has a very small electrode that can very easily become contaminated with oil. I think the G35, and 350Z however has a revised MAF, and at about 16k miles and 1 Reoil of my filter, its still ok.

 

Actually MAF problems related to oiled air filters is quite common among all cars utilizing the MAF system. The particles of oil from the filter can cover the wire elements of the MAF sensor. Over time, the oil collects on the elements which also attraches dirt which makes it past the filter. Once the grime and oil get thick, the MAF has problems getting accurate readings and sometimes the unit will fail. I know that with the 2002-2003 Maximas, MAFs were dying left and right because of aftermarket intakes. It turns out the combo of higher flowing air and the oil from the filters was killing the MAFs. Nissan has since updated their MAFs on that model.

I've run HKS and K&N filters on my 96 Maxima and I would occassionally get a slight amount of build up on the elements after 20K miles or so. I simply took a Q-tip dipped in rubbing alchol and wiped off the elements. You have to be super careful though because you can easily break the elements.

It appears that the MAFs on the G35/Z work fine with the oiled air filters. I suggest a couple things though:

1) Take a rag and wipe off your new filter before installing it. These filters usually have a good bit of residual oil remaining mesh. I think this excess oil is what causes the problems.

2) Don't clean and re-oil the filter all the time. K&N filters only need cleaning and re-oiling, but maybe every 30-40K miles. On a regular basis, remove the filter and shake out the debris and then wipe off with a paper towel.

3) When re-oiling the filter, don't go crazy with it. It doesn't take much at all.

 

I've never had a decent answer when I asked how the Greddy filter's perform....but most people I've shown it to seem to think it's not a good idea.

And it's been said a few times, but I've only heard of the MAF being damaged when you recharge the filter yourself, and put too much oil on.

 

yep - most writeups (including K&N) very strongly impress on you NOT to over oil.

In fact, with out a doubt it would be better to under oil, than over oil

 

When you measure the flow restriction [vacuum - pressure drop across element at full load flow highest rpm possible] of oem vs the lowest aftermarket you will see that the filter itself is not a problem as the MAr might have 7-10" Water column restriction and the filter at most 1.2"-1.5-1.8".

Nissan designs intake system to have a total restriction of less than 28" water column roughly a 1.0 psi loss from atmospheric pressure into cylinder. So 1/28 or even 2/28= 1/14 of 6.8% [density flow loss for 1 psi {13.7/14.7 psi}.............2/10 of a % improvement at best from oem filter to no filter at all.

OEM Airfilter have improved a lot in the past 15 years. NOT Surprisingly most oiled filters use old data from the big block V8 era and a stack of 15-20 year old air filters for comparison. Never any new data with modern oem filters.

 

All true. Buy the K/N for the sound and the longterm savings from it being reusable. Not for a performance gain. I have one and like it, but if not reoiled properly, it can create more problems than any savings you may get. User beware.

 

Speaking of Air Filter. I just got my K&N and I can't seem to pull out my old filter. Can someone help me?

 

I found these instructions in the DIY fourm:
https://g35driver.com/forums/faq-diy/17780-stock-engine-air-filter-replacement.html

 

I posted a DIY on replacing the air filter some time ago. Have you been to the DIY forum?
Third page of the DIY forum. Stock ENGINE Air Filter replacement thread. It's very easy to
swap out with this method. The tech at Infiniti showed me how to do it. With pratcice, you
can swap the filter in less than 2 minutes!