Quote:
Originally Posted by Sam Powell
Thanks for the nice comments and the advice. I have been thinking about how to handle the grill effectively and tastefully for some time, but need to learn more. Since the air cannot get around this grill if I block it off because of the big frame around it it seems I must direct the air behind the grill in the best way possible. Am I right about that? If I block off this grill isn't the air just going to build up on the frontal area and force the car to push the air down the road. Or is that not what happens? Can the air still get around that big lip around the grill area if I block the grill from behind. The guys who race these cars build a front cap for the grill that sticks out further and curves in a way that allows the air to move over the top and under the car easily. And I agree with you, I do not want to change the look that much.
As it is now there are no partitions behind the grill as are found in my other cars. These partitions in those cars divide the space into three areas. There is a the area right in front of the radiator, the space to the right of it,and the space to the left of it. All the air that gets through the grill in the grill opening in my 328 for instance must go through the radiator. Air that comes through the bottom openings and into the side areas is channeled into the intake air filter or the brakes. This is all done with rather flimsy, light weight polyethylene., but it is effective.
The challenge with the Dart is that if I build this same kind of partitioning, there is currently no place for the air to go that enters the grill on the side areas. So I must create a place for it to go, or block the grill off completely and force it to stay outside of the car and go around,which seems very awkward with the front end design. I could funnel the air on the driver's side into a pickup for the engine air cleaner. It sits right behind the radiator core support on that side. It currently picks up air from the fender well. I could open up the space behind the grill in the core supports on either side of the radiator, and funnel it into the wheel well and out that way. Or I could also create sloped blocks behind the side portions that direct the air through the radiator. None of these options seems real good.
So if I simply blocked off the entire grill on this design, where would the air go? How would it behave? This is key to figuring out a design here. Would it just ram its way through the air, or does the air still split and get around, over and under the car? I know from my reading that 55 mph is the speed at which the air no longer wants to separate easily. So it seems this concern gets more important as speed increases.
It boils down to this: Should I block it off, or manage the flow behind the grill?
Thanks for thinking about this as always. This is not as easy as dealing with a modern, slick front end design.
Sam
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Many of the modern cars have faux grille 'inlets.' Some elements of the grille are completely closed off.They're just there for aesthetics and the annual styling change.
Since the grille is so close to the radiator there's really no room for a diverging inlet duct and a smaller opening.
You might just block from behind with BBQ black material and leave an opening only as large as the fin and tube section of the radiator.
Also,if you've got a fender well-mounted ignition coil,provide some cooling air for it as you can cook the coil,or at least shorten its lifespan.
Ditto for ram-air to air cleaner.
This winter,when cooling efficiency is at its maximum,you could judiciously reduce the opening and let your temp gauge be your guide.
Hopefully you have a clutch-fan,or flex-fan,or electric cooling fan.All these reduce aerodynamic drag under the hood.