# Air filter or intake kit?



## Glennyboy (Nov 24, 2012)

Hi guys.

I'll probably get shot down in flames for this, but thought I'd as your expert opinions. :flame:
At my next service I'm due to have my drop in filters replaced.
Was just gonna get some k&n drop in ones that are about £90 for a pair and be done with it, but whilst browsing eBay the other day for a new A-pillar (mines bloody cracked somehow and nissan want the usual arm & leg for one!) I found the following and wondered what you though instead of the drop in k&n's.

JAPSPEED NISSAN R35 GTR GT-R HIGH FLOW 3" COLD AIR INTAKE KIT WITH K&N FILTERS | eBay

I have a stage 1 via Litchfields and will be going there again for my service shortly, so wondered if you thought these may add anything, whether it be performance (unlikely) or just a better sound. I appreciate the tune would need to be done again which I'll get with the updated software.

I assume they're an easy replacement although I could be wrong.
Any advice would be much appreciated guys.
Thanks


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## Stealth69 (Jan 6, 2005)

Some of them don't flow so well chap, they can upset the air flow causing all sorts of bonky goings on, I'd get some feedback from a tuner and perhaps buy one of theirs. If you're not going above stage 1 then don't waste your money chap


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## charles charlie (May 3, 2008)

Why not just get Litcho to install their intakes and have them retune the car? Why buy cheap narrow intakes?


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## Stealth69 (Jan 6, 2005)

Why bother with intakes in a stage two? Just drop the panel filters in and have it! Save money on mapping and parts


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## RogerWilco (Jun 3, 2015)

Personally I don't think a panel filter would really make all that much power. The stock airbox flows quite well up to a certain point and I would wager well past stage 2. 

IMHO the increased particle count due to decreased filtration ability does not offset the tiny bit of power you gain over the factory paper filter.


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## mindlessoath (Nov 30, 2007)

A. stock intake
1. paper filter - advantage best filtration maybe slightly less power (1-5hp maybe?)... but better filter is better. this is not cleanable but requires replacement when dirty.
2. serviceable filter... there are a few brands each with different quality and filtering. k&n are better than most eBay brands, but premium brands like green filter are higher quality, better filtering and higher hp (dunno if green filter has a drop in for the gtr or not, just using as an example). these types of filters are serviceable, either cleaned or re oiled. re oiling can be problematic and cause running issues that if too much oil has been added or not done correctly and it happens more than you think. using a serviceable filter can save money but you have to take the time to service them correctly, and a higher quality one will be more worth it if there is one available.

B. cone filter/ cold air intake
1. few different design's, but the one you posted is all from China and no real r&d was put into them and their quality is very sub par most of the time, requiring de buring, and cutting them to equal length's. the maf is also not in a good spot and requires more for the tuner to modify... so you will need a tune with them, plus your probably only offered the lower end k&n filters. its not like they won't work tho. just needs a bit more work to be put into them.

2. properly designed intakes like the gotboost intake can just bolt on without a tune for the stock replacement but the larger diameter requires a tune and most likely the 3" are not required until getting close to maxing out the maf signals on the 2.75". not to mention the gotboost offer green filters which I mentioned the benefits above (iirc these are not oiled like the k&n so an extra benefit), but GB intakes offer k&n too. I dont know any other intake that does all this and it was researched and designed by gotboost at a very fair price. quality of materials is good too.

3. carbon fiber and titanium intakes are pretty cool and look good and very light, as for quality you pay for what you get most of the time except in the case of false advertising or a tax added on for the word titanium or carbon when you get sub par materials, construction or quality checks. ie stay away from alibaba with this stuff lol and the same could be applied with their designs as mentioned above.

there are now two ram air systems we will see soon... JCR carbon intakes and ram air box (not released just yet) that has been heavily developed... and the groupe-m ram air for FBO and smaller builds (actually not sure about its maf diameter... plus the filters much smaller and is only using wet carbon not dry carbon autoclaved like the JCR. once more people get these installed well see the benefits on the gtr.

with a tune the cold air systems will net more power. either intakes (2.75 cold air or box filter) without a tune dont make much of a difference, I think you get more cool sounds. if you go FBO (full bolt ons) you will need a 3" intake so decide if you want that in the future and dont spend twice.

also note all Nissans race cars using the vr38 use the stock r35 airboxes.

I'm sure I left a lot out and didn't clarify a lot, but I dont have that much time ATM.


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## grahamc (Oct 1, 2006)

I run drop-in panels and have no issues with them, just get a clean at service time. 

The intakes are the limit on my car right now, but I am happy with 610/610.



mindlessoath said:


> ....
> also note all Nissans race cars using the vr38 use the stock r35 airboxes.
> ...


Exactly! 

Pic from N24H race, Nissan GT3 race car


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## Viper® (Oct 25, 2014)

I've read somewhere that the factory filters are the best option even over some aftermarkets like K&N.
Is this true ?
My car is completely stock.


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## RogerWilco (Jun 3, 2015)

Well ive seen tests that would put a k&n filter between 96 to 98% filtration efficiency. Ive seen paper OEM filters (for other cars to be fair) at 99.2 to 99.9%. That couple of percent difference makes a huge impact on the amount of dirt that makes its way into your engine.


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## mindlessoath (Nov 30, 2007)

k&n are terrible filters in comparison to green filter and stock filter paper.


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## charles charlie (May 3, 2008)

GT3 cars use the stock boxes simply because they are drop in. Access to remove and clean/replace the filter elements is super quick and reduces technician times dramatically compared to cone intake filters in the bumper.

GT3 regs from the FIA dictate power weight ratios and aerodynamic reductions on manufacturers to ensure a level ish playing field. The Nissan GT3 car runs 600hp so standard air boxes suit their requirements. Doesn't mean they are good enough beyond that though.


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## mindlessoath (Nov 30, 2007)

thats correct, you wouldn't want to run a 650+HP gtr on stock airboxes because you would be asking for more voltage from those 2.75" pipes and the Nissan race cars are all limited to under 600hp. plus all the other advantages explained by Charles

notice how they dont run Bov's on the race cars too  another race car feature, less to go wrong. 

they do have 800hp vr38 projects that still use the stock airboxes too, same reasons above and they are the best at filtering crap outa that expensive engine they built. ex DACiA DUSTER but can't find the pics with it.


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