If so how well did it work? I know it works, but I'd just like some to hear some first hand experiences. Any water get near the throttle body?

 

Heh heh. This doesn't really answer your question, but I actually removed the bypass valve from my Nismo intake. I really don't see a need for it. I'm never going to drive through any deep puddles in my Z, and the Nismo manual states you can get a little more power (presumably via smoother air flow) by not using that bypass valve. So, I removed it.

(That being said, I'm sure I'll drive through a big puddle tomorrow and hydro lock the engine, despite the fact that it's sunny and 80 degrees here.)

 

yeah i was pretty confident too. but oine day it rained hard i was 30 seconds from home and i ran into 1 foot deep water and couldn't tell b/c the entire street looked level and only 2-3 inches deep.

 

Wowsers. I guess I get overconfident living in the land of the dry. Fortunately that diverter valve looks pretty easy to swap on and off whenever needed. (It's right up in the front.) Maybe I'll stick it back on there during the rainy season here.

 

yeah, if u ever go through 1 foot deep water with a cai, my advice is to just shut off your engine. get out of the car and push it back out.

 

it works pretty damn well.

there is a video floating around the internet where they test the bypass valve on an NSX.
They literally get the air filter and submerge it into a bucket of water. The water just splash out through the bypass valve, and the NSX is fine and dandy.

So you know for a fact that it works, and if you have it, use it, better safe than sorry.

Someone needs to imitate AEM's design and integrate it into the Injen CAI, i'm sure they would sell like hot bread...

 

Went through a deep puddle and couldn't get the car to rev over 4k without bucking. No damage to the engine and the car dried out in a day. Do all the nismo CAI's come with the diverter or is that an add on?

 

So why is it AEM/Nismo says we'll get better power *without* the bypass valve installed? (It says so, right in the instructions.) My only guess is the increased turbulence in the air flow cause by the valve.

 

well, the bypass valve is just a sponge in the middle of the whole tubing thing. By having that sponge there, when your engine sucks air, you are probably sucking less than what you would normally suck, just because the air being sucked in through the intake might be diverting out through the bypass valve.
In other words, get a straw with a hole in the middle and suck on it, see how much you can suck form the other side of the straw and compare it to a straw without a hole.

 

Heh heh. This analogy works to explain how it prevents water from being sucked in if you submerge the main filter, but it doesn't explain why you might get worse performance by having the bypass valve installed.

Considering your straw-with-a-hole-in-it analogy: when you suck in through that straw you can suck in just as much air (if not more!) then if if there was not a hole in the side. More holes in the side would mean more places for air to come in, and thus potentially greater flow rate. However, dip the end of that straw in your soda and try to take a drink, and no soda comes up. That's what happens with the filter gets submerged in a puddle of water.

I'm guessing that bypass assembly might just add some bit of turbulence to the intake tract which may (or may not) cause a slight flow decrease. It's probably minimal, regardless.

 

Heh heh. This analogy works to explain how it prevents water from being sucked in if you submerge the main filter, but it doesn't explain why you might get worse performance by having the bypass valve installed.

Considering your straw-with-a-hole-in-it analogy: when you suck in through that straw you can suck in just as much air (if not more!) then if if there was not a hole in the side. More holes in the side would mean more places for air to come in, and thus potentially greater flow rate. However, dip the end of that straw in your soda and try to take a drink, and no soda comes up. That's what happens with the filter gets submerged in a puddle of water.

I'm guessing that bypass assembly might just add some bit of turbulence to the intake tract which may (or may not) cause a slight flow decrease. It's probably minimal, regardless.

 

Heh heh. This analogy works to explain how it prevents water from being sucked in if you submerge the main filter, but it doesn't explain why you might get worse performance by having the bypass valve installed.

Considering your straw-with-a-hole-in-it analogy: when you suck in through that straw you can suck in just as much air (if not more!) then if if there was not a hole in the side. More holes in the side would mean more places for air to come in, and thus potentially greater flow rate. However, dip the end of that straw in your soda and try to take a drink, and no soda comes up. That's what happens with the filter gets submerged in a puddle of water.

I'm guessing that bypass assembly might just add some bit of turbulence to the intake tract which may (or may not) cause a slight flow decrease. It's probably minimal, regardless.