I want to share an experience with AEM's CAI in case anyone out there is considering getting one. I got my '06 Enthusiast in July. Within a couple of weeks I swapped out the stock air box for an AEM CAI. Everything was fine until the first time it rained. My car was actually out in a parking lot when it was raining. When I drove off, it had stopped raining, but the roads were still wet. The throttle/fuel would cut off between 3500 and 4000 rpm. It was the strangest thing. I wasn't accelerating hard or anything. I'd accelerate slowly (due to traffic) and all of sudden it'd feel like the throttle had snapped shut.

Well, after that day, I couldn't get it to happen again, so I thought maybe it was some weird fluke, until about 3 weeks ago. Once again, it was raining on a day I was driving. (I work from home, so I don't actually have to do much driving). On this particular ocassion, I was just going to the gym. Everything was fine on my way there, in spite of the fact that it was a heavy downpour. During my workout, it continued to rain and my car got soaked (obviously). I start up the car to leave the gym, and I'm just slowly driving through the parking lot and it happens again! It happens all the way home! Same thing -- I get it up around 3500 rpm and boom! Everything just snaps shut. It's difficult to explain the feeling. It's more violent than the feeling of just simply lifting your foot off the gas. It actually jolts one forward into the seat belt. I started to wonder if it had anything to do with the TCS. The slip light never came on, so I thought it unlikely. But just to eliminate the possibility, I switched TCS off. It still happened.

So at this point, I realized there was a common denominator between both times this happened. Both times, the car had been sitting out in the rain. Both times, when I pulled out of my dry garage and into the rain, even though it was raining hard, no problem. The problem only arose after my car had been sitting out in the rain for a period of time. So when I got home from the gym, I popped open the hood to take a look at the area where the filter sits, and noticed some moisture. My hypothesis at that point was that water was somehow trickling in through the hood and dripping down into that area, because I did notice some streaks of water going from the top of the engine bay down into that little corner. I further hypothesized that the throttle was snapping shut as a protective mechanism in response to sensing some moisture entering.

Acting on this hypothesis, I ordered a JWT PopCharger and swapped out the AEM. Twice since then, it's rained, I've deliberately let my car sit out in the rain, and then gone for a drive. The problem no longer happens. So my conclusion at this point is that there's something wrong with the AEM CAI, either due to the placement of the filter element, or the filter element itself (as it was one of their new 'Dri-Flo' filters). Once I changed over to the PopCharger, the problem went away.

Just thought I'd pass this on to hopefully save someone else the aggravation.

 

I too went from an AEM CAI to a JWT. My experience in rainy-300-days-of-the-year Oregon was problem free. Storms, puddles, etc. were no problem. I suspect you are right in that your hood was perhaps leaking and water was running down to the filter. I dunno. Once I literally drove through 1.5' of standing water at 30mph and my AEM was bone dry. And I didn't even have the center splash guard on that day.

I just felt safer with the JWT in such a wet climate although I liked the AEM a whole lot more.

 

popcharger wins again

 

You should post photos so members who are not familiar with the AIM intake know what you are referring to.

I say impossible. The filter is in front of the bumper correct. Water would have to enter the filter and travel all the way the the motor. The probability of this happening is 1 in 1,000,000.

 

Yeah I know, it doesn't really make a whole lot of sense, right? But I'm at a loss as to what else it could have been. The key factor is that it never happened unless the car had been sitting out in the rain. I put emphasis on the 'sitting out' part because I drove through some pretty torrential downpours in the last month, but there was never a problem when I started out the drive from my garage where the car was dry. The problem would only rear its head after the car was allowed to sit in the rain, stationary, for a period of time. So what is it about sitting stationary in the rain that would have triggered this problem? And keep in mind that with the PopCharger, I've deliberately let my car sit in the rain for a few hours just to test, and nada, no problems. My thought was actually that rather than actual drops of water making it to the throttle, the filter was just getting wet and the ECU was maybe sensing an unusual level of moisture. I don't know if that even makes sense possibilities-wise, and I'll be the first to admit that I'm grasping for a logical explanation here. You have any alternate deductions from the circumstances?

As for a pic, this is the only one I have of my engine bay with the AEM.

 

Question. Did you have the traditional oiled-cotton filter with your AEM? Or did you have one of the new Dri-Flo filters they're using now? Because part of me wonders if this new type of filter material they've switched to is a contributing factor.

 

I had the old-school v1 AEM CAI. So it was the regular filter, not the new one. I'd be surprised if the new filter technology has anything to do with it but the Z can be really touchy so perhaps it is a factor.

Maybe in the 06 they tweaked the MAF/ECU or something?

 

They sell the BYPASS VALVE for a reason...

Without the Bypass Valve, unless you are in a dry state, dont bother with a cold air intake...

The Bypass Valve eliminates this problem... the NISMO Intake (basicly a re-packaged AEM) includes this part...

 

I live in Georgia. Not exactly as dry as, say, Arizona. But I wouldn't consider it wet like the Seattle area either. I NEVER drive through standing water. I had an AEM CAI on my last car (an S2000) for 4 years with no bypass valve and no problems whatsoever. So why should I suddenly need one for the Z? And why would I have no problems driving through a torrential downpour, yet if I leave the car sitting in a parking lot for 30 minutes, even if it's just a light shower, then suddenly there's a problem? Given these circumstances, it's as though you're suggesting that in this particular situation, a bypass valve is needed not for driving through pools of standing water, but for parking in the rain. Does that not sound a little odd? Think about it. If someone said to you 'Hey, this CAI is a pretty good part, just make sure you get a bypass valve so you can safely park your car outside when it's raining', wouldn't that sound a little bizarre to you?

Let me put it this way. You might be bang on the money that a bypass valve would have solved this problem. But if one needs a bypass valve to make an AEM CAI work correctly after doing nothing more than parking out in the rain, wouldn't one be better off to just go with a JWT PopCharger? And that's pretty much the point of my OP. If there are any noobs out there right now just getting started on their mods and trying to decide between the two, I encourage them to go with the PopCharger.

 

different filter placement... different car...

 

would have gotten the stillen over the poop charger since it has an actual functional heat shielding around the filter

 

Even so, would it be worth the money? Prob not.

 

in the past three weeks, i've had to take my aem cai apart to dry out twice, and gotten cel both times for mass air flow. just from the car sitting in rain/driving on wet roads, no puddles or submerged filter. ordered bypass valve yesterday.

 

Hmmm. I seriously had zero issues with mine (no bypass) in OR where it's wet like 300 days a year.

Had I seen a single error or issue I would have yanked it immediately.

 

I have the NISMO CAI with the by pass valve and have no problems driving in the rain.

 

+1 for NISMO & +2 FOR THE BYPASS VALVE.

 

Needing a bypass valve for driving through heavy rain and/or standing water is one thing. But needing one for just having the car parked out in the open while it's raining? That's messed up. Counting myself and Garyovich, that's two people in this thread so far who have had problems with AEM's CAI just from sitting in the rain or driving on wet roads w/o filter submersion. I think AEM dropped the ball on its design for the Z (i.e., filter placement).

 

While I agree that there seems to be an issue....if water is getting all the way down to the CAI when parked then that seems like more of a improperly sealed hood design flaw. That's my take (no pun intended) anyway.

 

Yeah, that's a good point. I have an '06 with 2700 miles on the odo. It's still in pretty much brand new condition. I wonder if there were any minor changes to the seals with the '06 model compared with previous years.

Actually, if you scroll up you'll see a snapshot of my engine bay. This is a little tough to put into words, but I'll try. Actually, no I won't. Here's the same pic, except I drew in a red arrow to show the path of water I see when I open the hood after it's been in the rain. Basically, it starts at the top by the windshield and then trickles down per the red arrow.

 

Ah, I see. Interesting. Let me look at my 03 and maybe we can pinpoint the difference.

But FWIW when I open my hood when it's been raining, water seems to head from the hood straight for my JWT. So perhaps I'm no better off. lol