I've wanted to do this since the C4s came out in 83, and the very aerodynamic Trans Ams of the late 80s replaced the front grill with a body panel. I remember reading a Popular Mechanics article during the first energy crisis in '74. They modded a Pinto a number of ways, but the biggest impact on highway gas mileage came when they backed the front grill with cardboard, forcing the air to get to the radiator via the spoiler under the car. I think the C5 and C6 Corvettes are bottom feeders too. Since I removed my batering ram/air reservoir, my car has been running a cool 170 degrees, so I thought I would try this finally. First I cut out a grill panel using aluminum sheeting.



After I painted the panels black, and reinserted the grills, you can't even tell that the grill is now non-functional.

I will drive it to work in the morning to see if my coolant temperture is affected. This should really up my top speed. I wish I had the guts to find out. When I was a kid, and the car was new, I had it up to 141mph once, verified with an onboard computer which used four magnets mounted on the driveshaft. With the 700R4, and the numerous engine mods, and the Pace Car Spoilers, and now blocked front grills, I wonder what my top speed could be?

 

I suspect you'll be fine, since you have the 3-hole lower panel and a functional air dam that actually ducts air all the way to the rad. But, you might find that you need thicker material...(??)

It would stand to reason that closing off the grill should improve your drag coefficient, whether by a measurable amount or not. One way to check without reaching terminal velocity would be to do a few before and after coast-down tests with no other changes.

By the way, the pace car aero package reduces C3 drag coefficient by about 15%, down to around .43-.44 C/D. So, it's certainly not a ricer type cosmetic add-on. (If you head north of about 85mph very often, you might consider bracing the center of your dam.) For a good read on C3 aero, check this thread: http://forums.corvetteforum.com/show....php?t=1419660

btw... do you have electric fans??

 

Yep, I have dual electric fans. My cd prolly sucks with these 275/40-17 tires up front. I'm going to try some other aerodynamic aids real soon, like venting the hood, and making the side vents more functional. Maybe I'll get the guts to try a top speed run. I'm not afraid of hurting myself, but of the ticket, and hurting the car. I'm no chicken. OK, I am. I ran a 13.2 second at 103 mph last year. Maybe with some of the improvements I've made in the last 12 months, I can get into the 12 second club.

 

Should create more down force

Your essentially creating an upside down air plane wing

 

WRONG! at the angle the grilles sit, it will cause lift. If you want to do some Areo work on a C3, extend the front air dam downward to keep air from going under the chassis. Good luck on staying cool on a 100+ degree day, I don't think you will if you are making decent HP (300+)

 

100+ degree days are rare here on the Central Coast of Cali. One of the reasons I left Texas. Well Uncle Sam assigned me here, but I stayed after retiring from the AF. I drove it in this morning, the temp was rock solid at 170 degrees, except when I climbed a long hill, and had to stop for a light at the top. It got all the way up to 180 degrees. I looked even closer at a C4 and a C5 parked at work. No front air intake, and my three bottom holes are bigger than their one. OK, one of my holes, the middle one behind the liscense plate, has a plate oil cooler. But I think cooling isn't going to be a problem. There are many that think 180 degrees is way too cool. I like cool.

 

I see what your after, but since your aluminum is on the inside there is still a pocket for drag in the grills themselves.(not much, for the the most part the air is still forced around them.)It will be an improvement,but (this is only a sugestion,I like what your doing!) it would be smoother if you was to put lexan over the grills on the out side.Just a thought?

 

I have been workin with the areodynamics of my vette for awhile now and this is the new front.It is very functional and almost finnished.The lower scoops have been on the car for about 3+yrs and work very well.(hood is vented and has ram air, side vents functional)I went through alot of designs and some worked better than others.



The center of the lower scoops is removable to make them two peice.



There are alot of things that you can do to improve your vettes aerodynamics.I enjoy all of the different ideas on this.Stay after it!

 

I doubt the grills will create much lift if any.

 

Interesting looking concept. Do you do the fiberglass work? If so how do you make the body in the shape you want it? What type of mold is used?

 

and do you have a picture of the car with the hood installed as opposed to laying on the ground...I rather like the look of your sketch but would like to see the reality of where you are at now.

thx

 

Regarding lift vs. downforce: If there is more aero pressure above the body than beneath, there may or may not be much of it, but downforce exists, and the greater the differntial in pressures the more of it there is. To have lift, there would have to be more pressure below than is present above. Simple enough, right?

However, a car is not a wing operating in open air, but rather a body in ground effect, in that the ground is acting as an element in the aerodynamic equation. True ground effect tunnel bodies aside, the less air that gets underneath and the better that air is extracted, the lower the pressure will be below the body, and the net result is more downforce and decreased drag.

That's why splitters and/or air dams are on every serious race car where the rules allow. And, especially with a splitter style air dam installed, closing off these grills just shouldn't result in a measureable increase of air going under the car, if any more...

As far as reducing drag, covering the grills can't hurt. Certain cagy stock car guys (can't believe I'm actually using a NASCAR reference) used to plug the radiator with bee's wax for qualifying because it would lower drag enough to get another mph or two. By the time they'd get to tech the bee's wax would be all melted out so they'd be legal again.

Bee Jay, I like your idea, particularly that it isn't noticeable, and hope it proves to be practical. Good luck, and keep us posted!

 

Oldguard 7, I do all the workmyself,If I'm makin a mold I'll usually use foam and shape it.Like a surfboard.This last front was done with fiberglass panels and pieces.I have done alot to the rest of the car also,and will be changin the flares soon.

Fauxrs 2, I have a few of the front on the car as it was gettin mocked up,I need to get some new ones!I just brought it back home from 6 months in storage and will be back into it soon.I have the whole project on another site.http://www.cardomain.com/ride/828811



Bee Jay,Sorry for walkin heavy on your thread,good luck with your project and keep us posted on your results!

 

BeeJay, what have you found out about this mod?

 

I asked him about that before he got his Italian toy (I'm still jealous), and he reported having no cooling issues.

 

This is good for over 250 MPH.

 

No coolant cooling issues at all. But I put a new super duper tranny in with a higher stall torque converter, and I started having trans fluid cooling issues. Man that tranny fluid got hotter than ever. I removed the grill panels to get more air to the trans cooler. That only helped marginally. Then I took the unused AC condenser and plumbed it as a trans cooler. http://forums.corvetteforum.com/show....php?t=1763667
Problem solved. I never put the grill panels back. But I never had any coolant overheating issues before I removed it. I may put them back and see if my trans stays cool.
Bee Jay

 

I am thinking that the condenser will be a little small. What I might recommend doing, that is if grille panels work, is putting a small tranny cooler over the center valance panel. I would think that the panels behind the grilles would force the air to go down and up through the valance.

 

That's been my belief all along, what with that splitter/air dam, but there could be some spillage around the nose. Another benefit I might mention is a reduction in RCS those panels likely afford, not that I'd know anything about that...

 

I'm lost! Please explain.