Under the Hood Exploration

LA_Phantom · 10-20-2006, 05:48 PM

Recently there has been discussion about an IAT relocation mod. Today I took the time to look under the hood and do some thinking. Because of my reading, I am aware of what others are doing with regard to their IAT relocations, but do not know how this mod alone can provide signicantly different (cooler) temperature measurements when an aftermarket "CAI" has been installed.

For those not aware of it, the K&N Air Charger CAI replaces the stock air box with a barrier that is supposed segregate the air pulled into the intake from the "hot" under-the-hood air. This barrier is open on the top and the bottom, which leads me to wonder how much it really helps in terms of bringing in air cooler than that which is under the hood. I suspect that Svede1212 will agree with this observation.

On the '05 GTO, the plastic radiator cover has small opening near the radiator overflow fill tube that appears to be a means by which cool air would be directed to the air box. I need to dig out my stock air box to confirm that this is the case. I guess air is able to flow this route when the hood is closed. In any event, I can see the possibility of air cooler than that which is under the hood being drawn into the intake when an air box is present. It certainly would be interesting to see the results of computational fluid dynamics modeling of the air entering the air box. What an aftermarket "CAI" buys the GTO owner is the ability to move a greater volume of air than the OEM setup. It does not actually bring in cooler air. In fact, if I were to haphazard a guess, I would say that the air drawn into the intake is actually of a higher temperature by virtue of the design of the "CAI". Again, this is not a revelation.

Back to the IAT relocation discussion. I would ask the question: How much cooler is the air expected to be on one side of the K&N barrier relative to the other? It is hard to imagine the temperature differential to be significant. However, I cannot dispute the results documented by others. I guess the air flow to the filter, by way of the aforementioned radiator cover opening, is sufficient to make the IAT relocation mod to work. However, as I mentioned in a previous post, the IAT relocation mod is but a step in the right direction. Without modifying the location of the air filter, or where the air is drawn from, the full benefits of the IAT relocation are not fully realized.

For air filter relocation, a good place to start is with something similar to the SS Intake or the Hardcore Intake.

I apologize for being long winded and writing in circles. I am trying to reconcile my path forward with respect to mitigating the issues associated heat soak.

-K

mechanic58 · 10-20-2006, 08:06 PM

You bring up many very good points. I've always been a critic of CAI's. I'm certain there was a whole group of engineers, asigned the task of designing the the OEM air intake and it's associated equipment. My car still has the stock one on it and I intend to leave it as such. It LOOKS better and I am also certain that it filters the air better. It is a known fact that a K&N filter provides LESS filtration than almost ANY other type. As far as temperatures are concerned, it doesn't take a rocket scientist to figure out that all those cheesy-a$$ed CAI's you see could hardly block THAT much heat. The only way to effectively get cooler into the intake is to DUCT IT there. Period.

LA_Phantom · 10-20-2006, 09:16 PM

Quote:

Originally Posted by mechanic58

The only way to effectively get cooler into the intake is to DUCT IT there. Period.

Matt, you sir have said a mouthful. It appears that we are 100% in agreement. Certainly none of the popular commercial "CAI's" actually do anything about providing cold air.

-K

Gonna_Try_One · 11-01-2006, 09:34 PM

While I will agree the boughten CAI kits are a bit lame in keeping out engine bay heat. There is some benefit if done right. Hence the reason why I built and sealed my own.

What I did notice when I had the stock airbox installed. Once it got heat soaked (the plastic in particular), it stayed heatsoaked. It would take a long time for it to cool down. This is not so with my current setup. IAT's change more rapidly. For those that don't remember my '04' does sport a Maggie, so IAT relocation is not an option, it's permanent home is in the intake manifold.

One thing that is unique to my set-up. Once the vehicle is under motion there is constant airflow moving through the sealed off section that my cone filter resides in due to the RK Sport hood, and the 4" hole cut in the inner fender where I use to have what is now referred to as a "hardcore" setup (I had done this before the term was coined). Due to street flooding in Baton Rouge during rainstorms, I was not comfortable with it, and removed it.

I'm waiting on my Omega thermister to show up, so I can modify one to install in my manifold to see if it will make a quick enough change there. Especially when I'm spraying the methanol.