I know this is an older thread but it's more info. I had the Airraid on my other HHR and although you really don't notice much if any, I figure I may go with the same set up. I really like how they designed it ..closing the hood down capped off the top and left the very front open to any rushing air that come through. It's just so easy, you just open the hood and there you go..easy access visually and maintenance wise. Oh and sounds good too!

 

I recently bought a cgs intake, looks like chinese crap. Wrong filter shipped ..... If you know anyone who can bend a 2" exhaust pipe you can achieve the same. Buy a k&n filter and your done

 

i made a home made intake and here is one that Tim did on his HHR
you need to get the filter out of the engine compartment
you get a 9 to 10 hp loss for every 10 degrees increase in the intake temperatures over what is outside air temp
for instance 85 outside, intake temp is 96 you lose 9 to 10 hp
do multiple runs down a track back to back and the temp is 100+. you will see your 1/8 or 1/4 times get longer and longer every consecutive run you make

the stock intake is fine just sucks changing the filter. the GM and K&N work great. air still comes from the wheel well just easier to change the filter and it is a better kind to increase mpg and lil bit of hp
hp gain from an intake is minimal
you will get more gain for $200 from a tune than any intake out there

Picture of my CJ inspired intake,with the filter behind the headlight and drawing cold air from the cutout fog light cover.

 

CJ....

You should check your figures in the air temperature vs. HP statement. You are WAY off.

As I understand it.....it is 1% HP loss for every 10 degrees ambient (actually it is 1.11% gain/loss of HP for every 10 degrees down/up ambient, if all other factors are consistent......barometric pressure, humidity, etc.) So theoretically, if you are "sucking" 150 degree (under hood) and the ambient is 80 degrees, with a vehicle rated at 174 HP @ an ambient of 80 degrees, your loss is just short of 2 HP (1.93 actually).

Understand this is theoretical. As fireman suggested, most people do NOT see extreme changes in ambient and intake temperatures, and as provided in my example, other than in a heat soak situation. Even with the STOCK INTAKE. In any event HP loss, do to intake temperature, is not and should not be a concern unless of very unusual circumstances.

Power increases recognized from "add-on" systems is provided by increased breathing (more air) through larger filters and/or "thinner" filter "paper"/media.

I've been involved in this process with GM and had ONE of the first GMPP intakes (10 consumer mules). During this period, I also witnessed the tests of aftermarket products and, I'll just mention, none produced hp to what most owners think. ON MY VEHICLE, the GMPP intake produced, approx. 3 HP (about 12 dyno pulls total, 3 HP average). The HP came from the filter, the package was marketing cosmetics.