Hi guys,

Can someone tell me how the rain trap works in the Nismo cold air intake? A picture would be great.

Im interested in fabricating a ram air intake. However, im worried about rain getting into the filter and the engine.

Thanks

 

Roark did a DIY ram for his Nismo CAI, check it out -->
https://my350z.com/forum/showthread....threadid=44933

 

When you say "rain trap" I believe you are referring to the bypass valve that sucks air from the engine bay rather than the cone filter when it gets covered with water. How it works is just physics, there are no mechanical parts involved. Try this experiment:

Get a glass of your favorite beverage. (water, coke, beer)
Take a straw and cut some decent sized holes in it (near the middle).
Put it in your mouth and start sucking air (you are the engine here).
While sucking air, put the end of the straw into the beverage and see what happens. You should keep getting air. I don't have a straw to confirm this, but this is the basic principle. If not, then you should at least be hydrated.

From personal experience, the bypass valve does work. I have copied Roark's ram air (see sig, noticed minimal performance gains) and went through several large puddles/splashes the other day at low speeds. I tested it by tapping the gas as I went thorugh the water and noticed that the RPMs dropped a bit for an instant, then picked back up. I think that's when the engine started sucking air from the valve rather than the filter.

I saw a video of a guy who worked at AEM (owner maybe) do a successful experiment of the bypass valve similar to the straw one with his NSX.

So if none of this made sense, the answer is yes, it's safe to use Ram-Air with the Nismo, I can't comment on other intakes but I'd say the bypass valve can't hurt.

 

ok cool. this helped a little. I dont plan on buying the Nismo CAI. I was just interested in the mechanism. So your saying that the only way the bypass valve works is if the primary air source is completely blocked. What if water droplets get sucked up through the intake? Do they get "trapped" anywhere? If not, wouldnt this pose a major problem to the engine?

Im basically interested to know how I divert caught up water in the intake before it gets to the air filter.

 

I believe the valve takes in some air even when the filter is not blocked, part of the trade-off with using it since the air is warmer. Also, it probably creates more turbulence as the air enters the engine...

From the AEM Website:

"The bypass valve may cause a slight loss in power due to the interrupted wall section created by the internal shape of the valve. In dyno testing we have found that the power loss is minimal. The bypass valve offers great security against hydro locking the engine in rainy conditions. If maximum power is the requirement, we suggest that the bypass valve be used in the rainy season and when racing use a coupler hose to make a smooth section where the bypass valve goes."

I can't confirm what would happen if water got inside the lower portion of the intake. My best guess would be that if it was stuck to the inner wall of the intake, it would climb up until it reached the bypass valve, and stop there... But if that's the case, the valve isn't performing like it should. If you haven't seen it, here's a link:

http://www.stillen.com/Sportscars_de...d=24694&page=1

Hope this helps.

 

BTW - The Nismo and AEM are basically the same, the Nismo includes the bypass valve when you buy it.