: CTSV Engineers COME IN...



dhpro
08-22-11, 08:13 AM
A few engine bay questions:
1. Why is the hood sealed? Where is the air being directed - I'll assume out the bottom? Can I further assume that the sealed hood is deigned to improve the rad & heat exchanger efficiency?
If thats the case:
2. What happens when a hood like Spectre's is installed with heat extractors, that will basically alter the air flow dynamics by sucking air out the top front? Theoretically, this sounds proper as it wud drag all the incoming air thru and up across the cooling fins? If those fender vents are functional, wouldnt it imply underhood temps/airflow was an issue - nothing is done for nothing IMO.
3. The plactic shroud/engine cover...wouldnt this only contribute to underhood temps? The blower must only have to work harder to stay cool with all that heat trapped under it?
4. Air intake: Is the OEM design with the rubber ribbed portion on purpose? Is this to slow down the air and create turbulence before entering the TB? If so, why? We've all seen the startling results from even this minor mod
These might seem like minor issues, but as all u guys finish up the major mods and start dialing in the ponies, the incremental power and efficiencies become more important. GM engineers spent millions on these small elements and I doubt much was left to chance. An engine cover like ours isnt cheap, and seems expensive for aesthetics alone as an example, and neither are the 2 little cones on the intake tube before the TB...

mannyz
08-22-11, 08:26 AM
Great questions I'd like to know the answers to as well.

Blakester
08-22-11, 08:44 AM
Look foreward to qualified answers.

Cadillac Tony
08-22-11, 11:21 AM
A few engine bay questions:
1. Why is the hood sealed? Where is the air being directed - I'll assume out the bottom? Can I further assume that the sealed hood is deigned to improve the rad & heat exchanger efficiency?
If thats the case:
2. What happens when a hood like Spectre's is installed with heat extractors, that will basically alter the air flow dynamics by sucking air out the top front? Theoretically, this sounds proper as it wud drag all the incoming air thru and up across the cooling fins? If those fender vents are functional, wouldnt it imply underhood temps/airflow was an issue - nothing is done for nothing IMO.

The fender vents are barely functional, if at all- they're a cosmetic feature. Considering the CTS-VR uses an extractor hood (and the fact heat rises), you would most likely see reduced temperatures.


3. The plactic shroud/engine cover...wouldnt this only contribute to underhood temps? The blower must only have to work harder to stay cool with all that heat trapped under it?

I'd be interested to see someone with access to a camera and probe test it with/without. I'd be surprised if it made any real difference considering the volume of air being moved across the engine by the fans. Most engine covers are made to conceal valvetrain noise, and the one on the CTS-V is very thin and only covers a small portion of the supercharger lid.


4. Air intake: Is the OEM design with the rubber ribbed portion on purpose? Is this to slow down the air and create turbulence before entering the TB? If so, why? We've all seen the startling results from even this minor mod
These might seem like minor issues, but as all u guys finish up the major mods and start dialing in the ponies, the incremental power and efficiencies become more important. GM engineers spent millions on these small elements and I doubt much was left to chance. An engine cover like ours isnt cheap, and seems expensive for aesthetics alone as an example, and neither are the 2 little cones on the intake tube before the TB...

The accordion section is there to make the tube flexible enough to be installed and removed. That's not a problem when you've got a cone filter at the far end not bolted down to anything, but with the factory airbox you need some flex in the tube to be able to put it on at the factory or remove it for service (unless you want to unbolt the airbox from the body every time).

As far as the little "cones", I'm guessing you're referring to the Helmholtz resonators. They're used to eliminate unwanted sounds from the intake- read more about here (http://en.wikipedia.org/wiki/Helmholtz_resonance) (see "applications")

thebigjimsho
08-22-11, 11:40 AM
All I know is if your plastic undertray mounted from the diffuser to the subframe comes loose, you will get enough turbulence to flap your hood at the base of the windshield at 100+mph. A good 1/2-3/4" deflection. Try moving that by hand. You can't...