Monday, November 4, 2013

Weather Testing the TMCAI

Probably the most frequent (and only) concern I hear and read about with a Top-Mounted Cold Air Intake is hydrolock.  Essentially, the worry is that this system will invite water to soak into the air filter and leak directly into the manifold, causing a whole slew of problems for the engine.  As such, this car will sort of be a Mythbuster, taking those concerns in mind as I drive it through different weather conditions.  The setup I have on the RS uses a 45° Pipe connecting the air filter box to the manifold with a K&N Air Filter on it.  I recently cleaned and recharged the filter shortly after switching to this setup.

The past week that this setup has been on the car, it has been rainy and windy, so conditions have been good to check and see if the worries folks had before would hold up.  In the rain, I took the RS up to 70 mph on the highway and then checked the system upon arriving home.  The filter was slightly wet, but the box and manifold were bone-dry.  There were no signs of any leaking through the filter after a 15 minute trip.  When it was windy (gusts up to 40 mph) I drove through lots of dust and leaves on some fun roads.  There was a wall of dirt getting blown around on a wide-open field that had been hit hard by a flood some time ago.  The silt still sat on it like a desert and wind was blowing the sand 30 feet up in the air.  Again, checked the filter, checked the intake, and things were still working well.

I'll keep checking things out as I drive the RS through more Subaru-worthy weather.  So far, looks like I'm busting this myth.


  1. It was nice to read

  2. Thanks for the update. I'm subscribed to you're thread on DR as well. I'm going to get one of these for my 04 just need a little time ...Gorilla is a cool company.

  3. What did you use to make the filter box? What size filter did you use?

    1. I simply up-turned one half of the stock airbox. It uses the stock air filter size, too. I simply used a K&N filter since I already had one in my car.