FYI - NASCAR race cars do not use cold air intake tubes so there really can be no conversation about whether NASCAR thinks smooth or ribbed is better. They just suck cold air in at the base of the windshield.. You know, the old fashioned way.

 

[Pulling from the front of the vehicle you are mostly getting 140-degree exhaust fumes from other cars on the highway - but not "cool air." And certainly not fresh air!

The search continues for "cool air." [/quote]

But, Mike......

wouldn't 140 degree air be better than 195 degree air from the engine compartment????? Hmmmm, thats a difference of 55 degrees. I'm sure there is an engineering principal in regard to "so many degrees reduction equals so many HP".

 

I don't know sh*t about NASCAR other than really fast and left turn.

 

 

Not always, take a look at Watkins Glen.

 

See, that proves I don't know sh*t about NASCAR.

 

I will make people angry with this, but I must speak my mind. I believe there is beauty in function. Scoops were originally used on race cars, then high performance street cars, in order to get cold air or fast moving air to parts that needed it (ie brakes, radiators, engine intake). In the beginning, when factories put on scoops they were functional. With emmission laws or for whatever reason, some cars had plates that prevented the scoop from working but was easy to remove (Trans Am). Others were just to make the car look like a race car, like the 340 Dodge Dart. Chevy even painted a scoop on some of their Camaros.

A non functional scoop actually detracts from performance by increasing wind resistance. I don't see the point. It is easy enough to cut a whole through the hood and make it work, and this would be GREAT for cooling off the engine compartment. If anybody has ever tried to work on their engine after driving, you can not lean against anything. There is a rubber seal around the compartment, so GM is intentionaly trying to either keep the temperature high for some reason, or prevent air turbulance.

Personally, I would love to replace the hood with a nice, light, fiberglass one with a molded in scoop. Less weight in front, better air flow for the engine, etc. Molding scoops to metal hoods frequently results in cracks since they have different expansion/contraction rates and temperatures. And the hood flexs when it is opened and closed.

 

OK, Being an oldschool mechanic, I'll say this about CAI. really Cold vs. Hot in general. Back in the 50's and 60's, all cars had a 180 degree thermostat. Back then it was correct to be cool. Then as the emissions thing came about, it was decided that warmer underhood temperatures were needed to get the fuel and air mixture right to burn properly and get the gas mileage that they are getting today, and to reduce emissions, so the normal thermostat now is 195 degrees. As far as NASCAR, they warm their cars up before they go racing, if you ever watch. why do you think that is? Also, if you are after tons of HP, then Cold is best, guess that's why dragsters run stone cold engines, but today it will take your computer controlled miser a little while to adjust to the air temp, it does have a barometric and temperature sensor that constantly adjusts the Airfuel mixture to the engine. If I start my car of the morning and try to drive away immediately, it will stumble. The computer remembers the last settings until new ones are received. All this about scoops and fresh air is great, and probably the best thing would be to not have any thing between the outside air and the intake, but we can't do that. Personally, I wouldn't cut on my new or old car to make anything different about it unless I was doing a totally modified street vehicle for a hobby or experiments. By the way, don't put a 180 degree themostat in your HHR unless you can change the computer. That will give a cooler under the hood temperatures, and cause the engine to run rich( Less gas mileage).
As for the thread, no, no hole in my Bumper, Hood or anywhere else. The looks of my HHR was one of the reasons I bought mine, gonna keep it that way. BTW, the reason I bought mine was for the gas mileage, keeping my foot out of the throttle has helped my gas mileage the most.

 

I am not an engineer, nor do I play one on TV , so take this with a large grain of salt; Regarding the 40's era 'fresh air' scoop in front of the windshield. The ductwork can have a screen on the entry at the 'scoop' for leaves, gum wrappers and small birds. In the 40's the scoop itself could be opened or closed from the inside. Inside the duct, as it makes the 180 degree turn [smoothly] to get the air back up front to the engine, there could be a slightly lower area, or 'sump' to collect the rain that strikes the rear of the scoop as it enters. I am not talking something as radical as a 'P' trap like under your kitchen sink, but just a slightly lower area [1/4, 1/2 inch??].
As for snow, hmmm, thats got me stumped. I guess if it is snowing, the ambient air is cool enough? Keep the vent/scoop closed at that time.

C'mon, somebody else refine this or educate us on why it isn't the way to go, please?

 

I'm not sure how helpful this information will be as regards this discussion, but here is some info I found at WIKIPEDIA. It also has information on other types of intakes as well. I will continue to search if more info is needed.