Air Filter

[dcnsx]

Hi All.

I opened my airbox yesterday and found the oem filter was a tad dirty. So I've thought about the opportunity of fitting an aftermarket unit, like a pipercross for example. What are you thoughts regards these oiled filters?

Cheers

[goldnsx]

I'm avoiding them. Tests have shown they let too much dirt through.

[The King]

I'm avoiding them. Tests have shown they let too much dirt through.

It is easy to over oil the filter with excess oil getting into the throttle body.

[Kaz-kzukNA1]

Unless you want enjoying the induction sound (noise), no benefit at all at partial TH region.
For C30A engine with just the aftermarket header and exhaust, again no benefit even at WOT despite using the remapped ECU. It’s just that the Eng is not requesting any extra air at all.

For C32B, you may see some benefit only at WOT region but on street driving, how long can you hold at WOT?
Because of this, even with the use of high lift camshaft, many tuned C32B engine owners stay with OEM airbox and OEM air filter in Japan to reduce the induction noise for street driving and also to prevent the potential extra dust into the engine.


From what I saw on many engines with aftermarket air filter, personally, I won’t use it on mine.

It requires careful control on amount of oil to be applied after cleaning and most of the time, the extra oil residue will result in sticky gunk on the TH butterfly and at idle air passage.

You need to be very careful on whether your aftermarket filter is Dry or Wet type as per this blog;
http://www.nsxcb.co.uk/entry.php?1770-Apexi-Air-Filter






If you have a chance to look inside the VVIS chamber, you will see the difference.
With the aftermarket filter, quite often, you will see sticky super fine sand like debris coated with oil.









With OEM filter, you will only see the trace of TH coating applied to the VVIS butterflies.
This coating is based on the material perfectly safe even if it was swallowed into the engine.


Kaz

[dcnsx]

Thanks for your reply's chaps. Kaz, I think you have made my mind up for me! OEM it is, some things are best left as Honda intended.

[Pride]

Hi All.

I opened my airbox yesterday and found the oem filter was a tad dirty. So I've thought about the opportunity of fitting an aftermarket unit, like a pipercross for example. What are you thoughts regards these oiled filters?

Cheers

Hi Dave.

Interesting.

I have to say that I never asked this question before taking the plunge but had I done so I would probably have come to the same conclusion as you and not of bothered after reading the responses.

To be honest I was really just looking for a more throaty induction note, which I must say, this kit certainly gives in abundance.

Although Kaz has seen dirty throttle bodies with after market kits fitted I can only say that my experience of dirt getting through is comparable to that of the oem induction kit and I've had my car nearly 20 years now.

There are many induction kits availible for the NSX, many do not give any gains over the factory setup. Downforce is one of only a few that give real gains and proved so by Science of Speed.

Downforce intake is one of the most sort after and best intake systems availible, it is similar to the Mugen design, made from Carbon Fibre and very light. It looks great in the engine bay also.

My kit has the optional extra's that were offered. It has the upgraded Carbon Fibre back plate over the Alluminium plate that comes with the kit. Which i also have and use.

The kit includes the much larger Intake scoop, (which I'm sure is what gives it it's distinctive induction note) and replaces the restrictive much smaller factory version. However some holes have been drilled in it as it illuminates the possibility of any water sitting in the scoop after a wash or rain.

Here are the parts:

https://www.scienceofspeed.com/index...df-aaa550.html

https://www.scienceofspeed.com/index...x-1991-05.html

I think provided you service the filter kit accordingly then only positives will be gained.

[goldnsx]

A scoop attracts double the amount of dust than the OEM one. The sound is nice though.

You can do an engine oil test. High silicon (dust) is very bad for the engine.

[Pride]

A scoop attracts double the amount of dust than the OEM one. The sound is nice though.

High silicon (dust) is very bad for the engine.

So you think the SOS kit is bad then how about this:

[goldnsx]

Nice trumpets but...

[wixer]

Interestingly, on the subject of induction noise, I've noticed, while I have the wheel arch liners removed, that there is a helmholz resontator as part of the OEM intake ducting. I'm guessing Honda fitted it, to get the noise to a certain DB level, to meet drive by noise regulations.

Will the removal or blocking off of this part of the system make any difference to the induction sound ?