grill block idea
 

rather than just blocking off the grill, how about making a grill block that goes in front of the grill, and slopes out toward the bumper ?

if you would post the car you have it qould help the conversation

I have an 84 crx hf. but I think most cars , in general , would benefit from a sloped grill block. if you just put a grill block on most grills, it is going to be straight up and down, which can't be good for aerodynamics.

Crx
 

Honda did a pretty good job of grille-blocking on the production CRX.
If your's is non-AC you will already have an internal full-block panel that closes the hole where the condenser would reside.
Some of the grille has 'dummy' sections.
I fabricated a complete fiberglass nose with integral Walter Korff pinched inlet duct.I can't tell you that it showed that strong at the pump.It hardly showed near 100 mph at Bonneville.
I would recommend rocker panel extensions to get the sides even with the tires.
The front wheel wells are bigger than need be.Some of this can be closed off at the top without interference with the tires.
Rear wheel skirts can be cast directly on the car with a proper release in place.
Leave the mirror(s) alone.They are plenty fine as is and Bonneville proven.
The underside needs a cleanup with sections of belly pan and diffuser.
The big savings are at the back with some boat tail.One foot of length will get you into 60 mpg territory at 55 mph with the other cleanups.:)

mine has a.c. but it doesn't work, and I planned on removing it anyway.

AC
 

Only one of my California cars had AC and I never used it.The climate was so good there was rarely any call for it.
If you ever head this way in summer though,you'll wish you had it.

I made mine a bit pointed at front bottom, so at bumper it is inverted "V" shaped, and then tapers back at sides to meat headlights, and tapers up to merge with bonnet/hood curve, don't know if it is better or not, the main reason I did it was to try get a more gentle curve where grille block meets bonnet, so minimise risk of seperation.

"Meat headlights"... can I post this? Pretty please???

http://cdn04.cdnwp.thefrisky.com/wp-...ra-425x283.jpg

Re: front: doesn't seem to matter much if the leading face is vertical or slanted, as long as it blends nicely with top and sides.

This is basically what I have done on my car. Made a sloped form that sticks out in front of the OEM grill and bumper and which contains a driver adjustable grill block with an grill inlet below the stagnation point of the grill block/nosepiece.

Bacon makes everything better...