Yeah! :cheers:

 

Actually, Dave Hill said in an interview when the 2001 Z06 came out that opening that area DOES degrade aerodynamics slightly, but it was one trade off they made for increased horsepower on the Z06 since the Z06 is targeted at the performance enthusiast.

I for one am not concerned about such a small decrease in overall aerodynamics.

 

I thought it is interesting to see the 2001 (and as another Forum member pointed out the 1998) service manual drawings of the "air deflector" as GM calls them (suggesting they have some air function). I think they were originally designed to be open. :yesnod:

They are shown with slanted slots cut in the top of them to send the air up into the engine compartment. Not sure why these were not put on our C5s. I guess another case of cost saving in manufacturing being more important than a performance improving design idea. :smash:

 

You can also remove screens, from frame and powder coat any color you like.

 

Information - Dave Hill

"The C5 coupe and convertible are extremely low drag designs, (Cd = .29 for the coupe, .33 for the convertible), enabling their owners to avoid gas guzzler taxation and enjoy excellent real-world fuel efficiency. Their grille slots are not functional air inlets; all of the air in front of the car flows over or around it, doing so with minimal drag. The only air that flows "through" the car comes from underneath it. The Z06 trades some fuel economy for higher performance, by opening the grille slots to achieve slightly lower engine air inlet temperature under certain conditions. I have notice some owners modifying both fascia grilles and the aircleaner. Owners should be advised that engine damage may occur should they drive through standing water with these modified parts on their vehicles."

You be the judge.

 

I did as some others and drilled holes in the stock shrouds. I plan to add the Z06 screens sometime this spring.

 

Exactly. You be the judge. That's the same quote I'm talking about. He was referring to the Coupe/Convertible when he said

Read it again.

He's saying that on the Coupe and Convertible, the air flows around or over that area because of the fact that it's closed. He wasn't talking about the Z06 at that point. He next talks about the trade off they made on the Z06 by opening the area which did affect the drag.

 

[QUOTE]Information - Dave Hill

"The C5 coupe and convertible are extremely low drag designs, (Cd = .29 for the coupe, .33 for the convertible), enabling their owners to avoid gas guzzler taxation and enjoy excellent real-world fuel efficiency. Their grille slots are not functional air inlets; all of the air in front of the car flows over or around it, doing so with minimal drag. The only air that flows "through" the car comes from underneath it. The Z06 trades some fuel economy for higher performance, by opening the grille slots to achieve slightly lower engine air inlet temperature under certain conditions. I have notice some owners modifying both fascia grilles and the aircleaner. Owners should be advised that engine damage may occur should they drive through standing water with these modified parts on their vehicles."

You be the judge.
[/QUOTE

I see three points here...

1. If opening areas like this do not allow air to flow "thru the car", why does the car have even smaller opening for the brake cooling ducts? By reasons above air should flow up and over the car and not enter these ducts. Therefore are they not "functional" and a waste of resources. Why are they there? Maybe they just look cool?

2. Opening this area does give higher performance (e.g., Z06). Are the C5s really that much more fuel efficient than Z06s that vette owners really care about it? Sounds more like a marketing discriminator to add a performance gain design factor that costs very little to add to both the C5 & Z06 (shown in C5 service manuals), but adds justification to a higher Z06 price.

3. Lastly, don't forget to add the "we will void your warranty" warning to the after market parts community that in many cases tries to pick up where GM dropped the design & quality ball IMHO.


[Modified by Vetts Forever, 3:05 PM 3/8/2002]

 

Another point relating to this design alluded to by a post above concerning the possibility of non-functional brake-cooling ducts.

What would be the cd if the fog light slots had been totally eliminated and the fog lights were flush-mounted in the fascia. This would probably have produced a more efficient design than the blind scoops that are there now. What happens to the air that slams into these closed pockets at high speed? There must be turbulence created by the rebounding air from these pockets that disturbs the laminar flow making it's way towards the hood and under the car. It'd be interesting to see wind tunnel tests of the stock setup vs. this modified super-smooth front fascia. I suspect that the overall air flow would be improved in the latter.

Someone else mentioned the aborted slits in the foglight surrounds that never made it to production. It seems that Dave & gang were considering enhanced passive cold-air induction up to the last minute. Was increased danger of water-injestion the deal-breaker for the slits? Also, the Z06 was designated as the hipo racer of the family but Chevy knows good and well that a statistically significant number of owners are going to use them as daily drivers or at least frequently enough to get caught in the sudden rain shower. Why risk the injestion problems with them but not the coupes/verts?

I'm a design engineer myself, and I know that I've purposefully designed products that were capable of certain functions but I discouraged customers from using them because it was a "cheaper" version of the product marketed as the flagship. It's good business to take advantage of economies of scale afforded by common parts/configurations and gives you lattitude for future "enhancements".

Chevy has a long term product plan for each product line. (Heck, I already know pretty accurately what my company will be releasing a couple of years down the road - most companies do.) Chevy, of course, knew the Z06 was eventually to be released as the hipo version and probably conceived the C5 design with it in mind, cold air intake slots and all. Why not put fog lights there for the coupe/vert in the meantime to justify the slots?

Anyways, I'm just speculating and this is JMHO. :D

Ed

 

Maybe I'm missing something... are we all talking about the SAME screens? These are the screen (WCC) I'm talking about...and there ARE openings for the existing fog lights.




[Modified by mikecoffin1, 1:06 PM 3/8/2002]

 

Obviously you didn't have any problem with the WCC cold air screen quality like a couple of the guys have reported. I was also planning on having a dealer do my installation. They told me it would be about a one hour job. Do you have a picture of your car that shows the screens? This debate on "to screen" or "not to screen" is about 50/50. I appreciate the great information on both sides of the issue. My car is not a daily driver and never close to be driven in the rain, so I'm not concerned about water. I know it may only make a slight difference in performance, but, what the hell.. every little bit helps!

 

yea, Mikecoffin1, those are the screens I am talking about.

 

Sure. Here you go:





p.s. You don't really notice the screens at all when they're left stock black if you look at the car from just a slight distance, because that area is always in a shadow as you can tell by my 2nd pic. I primarily bought them for the functional aspect. :cheers:

 

A Twin Flow intake and cold air screens were one of the first mods I did to my car. I understand that the debate rages on, but I can't possibly understand how opening up that area could NOT allow more, cooler air into the engine compartment. One downside (minor) is that I live in a sandy area and I do get a little more sand in my engine compartment. No big deal, I just wipe the engine down with a damp chamois every time I wash the car. I figure, if the sand's getting in, then the air's getting in too!!

BTW, Yes, the screens are a M.F. to put in. After I did mine, I posted a tech tip about it. You can read it here. Hope it helps.

Dave :cheers:

 

For what it's worth, I have the cold air screens on my vette and it seems to be working ok.