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| Aerodynamics of front end. https://www.slantsix.org/forum/viewtopic.php?t=46841 |
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| Author: | sandy in BC [ Mon Oct 31, 2011 6:00 pm ] |
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 Here is a photo of my old 69 Dart. Note the spoilers on the trunk and at at the top of the rear window. These are both station wagon back window foils. The one on the trunk is from an Aspen and the roof....a 60s Chevelle(I think). I used them to keep the trunk area and the rear valance free of snow,,,,,,but the inproved aerodynamics also helped with fuel cosumption. |
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| Author: | Reed [ Mon Oct 31, 2011 6:41 pm ] |
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Sandy's Dart is what I was thinking of with the spoilers on the roof and trunk. |
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| Author: | Sam Powell [ Mon Oct 31, 2011 7:27 pm ] |
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Those "spoilers" both look very tasteful and doable. Thanks. I thought it was interesting in the page that was linked up top they described a 15 year old Nissan as "boxy". Those guys don't know what boxy is. Sam |
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| Author: | exoJjL [ Tue Nov 01, 2011 2:59 am ] |
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I've always wondered if those vents on my 73' that are underneath on either side of the dash; when opened would create less drag. In my Plymouth Operators manual they describe the vents as "When opened they create a flow through effect." You certainly can feel more air coming through them from 25 mph to freeway speeds. |
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| Author: | exoJjL [ Tue Nov 01, 2011 3:12 am ] |
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Quote:
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| Author: | Sam Powell [ Tue Nov 01, 2011 4:56 am ] |
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Quote: Here is a photo of my old 69 Dart. Note the spoilers on the trunk and at at the top of the rear window. These are both station wagon back window foils. The one on the trunk is from an Aspen and the roof....a 60s Chevelle(I think). I used them to keep the trunk area and the rear valance free of snow,,,,,,but the inproved aerodynamics also helped with fuel cosumption. Sam |
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| Author: | sandy in BC [ Tue Nov 01, 2011 6:19 am ] |
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http://www.arrowtipi.com/images/instruc ... t-7_lg.jpg |
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| Author: | slantvaliant [ Tue Nov 01, 2011 1:33 pm ] |
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Aero improvements can be tough to document, because of the many variables. Most of the experimenters I see online spend a lot of time on videotaping tufts of yarn taped to the car, trying to smooth the airflow. I assume you don't want to change the basic shape of the car - as cool as a Dartona or Swingerbird might be. Belly pans show a lot of promise, but can be tough to implement in a street car. You'lll need a source of lightweight, stiff material. Some use coroplast or aluminum sheet. Look at the changes NASCAR teams made in the late 60's. It might be counterintuitive, but effectively blocking off the grill so the front is not concave might help. Optimizing the grill openings for cooling will take many iterations. I've considered making a grill "cover" with radiused radiator entry for my '64. A little paint and a fabricated rod grill would provide camouflage. For the rear, yeah, there are problems. I'd look into the Kamm effect first. To get the cleanest break,a wickerbill might work. Simply a short vertical fence to put the bubble where you want it, and to keep it small. Kind of what Sandy has done. An alternative would be vortex generators to "delay" separation. They're all over ebay. Might help a bit, if you don't mind little plastic shark fins on your car. Buy some yarn and tape, and have fun. 
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| Author: | exoJjL [ Wed Nov 02, 2011 3:33 am ] |
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I think rear fender skirts are a good place to start. Think about it air flows along the side of the car and some past the tires behind the diff and causes drag back behind the rear bumper. |
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| Author: | Sam Powell [ Wed Nov 02, 2011 5:05 am ] |
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Thanks so far with the ideas. They have been helpful and stimulating. I am going to start with sealing up the upper edge of where the grill meets the underside of the hood. As someone said, it is hard to describe in words, but the hood sticks beyond the grill by about 2 inches, maybe three, and there is as gap between the top of the grill and the hood. The underside of the hood is not smooth at all. I am going to put a flat sheet of aluminum on the bottom side of the hood that extends back to the radiator core. Then I plan to seal the top of the grill to the underside of the hood. It seems like making this seal slope back from the front of the hood down to the grill might split the air a bit and direct it all into the radiator. I know later models of the A body cars had a large rubber seal that sealed the underside of the hood to the radiator core. But it seems like something could be done earlier in the airflow than that. The goal here is not to turn it into a modern car in function or appearance, but simply improve what is there in small ways. This is essentially what I have done since I have owned the car. And the teasing comments I got early on in this thread are nothing compared to those I have gotten from many, many folks since I first got this car. Of course some admire it, but early on, many thought I was delusional for fooling with it. So I have had to learn to let those things slide off and not take them seriously. Those who were Mopar fans all wanted me to just "drop a hemi" in it. Those who weren't couldn't figure out why I didn't get a Chevy. "What will you have when you are done?" was asked many times. So, for those who tease about this effort at improving airflow on a brick, be glad I am not influenced easily by those kinds of nay sayers. Otherwise I would be on the Chevy forum now. In fairness to the teasers, if I had been more specific with my early questions, we would not have gone down the Super Bird path on the thread. Later edit: It just occurred to me that maybe the louvers I put on the top of the hood will improve the underhood airflow. They create a low pressure system over them at speed that will help draw air out from under the hood. I can see that under the hood is a major air trap. Most of the air must flow down through the tranny tunnel and out the back, but allowing some out the top must be a good thing. . Some cars have enormous air vents out the side of the fenders. These little BMW M-3 vents are kind of a joke in that regard I guess. What would happen to the cooling if I blocked off the grill from behind entirely? I do have the hole cut in the bumper down low for the innercooler. Most modern cars have very little frontal opening. Sam |
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| Author: | exoJjL [ Wed Nov 02, 2011 5:21 am ] |
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Quote: just "drop a hemi" in it. Hemi's are not as cool as a /6.
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| Author: | Sam Powell [ Wed Nov 02, 2011 5:30 am ] |
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Quote: Quote: just "drop a hemi" in it. Hemi's are not as cool as a /6. Sam |
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| Author: | exoJjL [ Wed Nov 02, 2011 5:35 am ] |
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Quote: Quote: Quote: just "drop a hemi" in it. Hemi's are not as cool as a /6.haha  
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| Author: | slantvaliant [ Wed Nov 02, 2011 8:46 am ] |
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When working with airflow, test and record. Air doesn't always do what we'd like or go where we think it will. Hence the tufts of yarn taped in various patterns and places, to give a visual clue of the airflow. Oh, and what it does at one speed may not be what it does at another. Air might be flowing out through the louvers, but there might be enough of a high pressure area at the base of the windshield to prevent it. Think "cowl induction". "In God we trust. All others bring data." |
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| Author: | Sam Powell [ Wed Nov 02, 2011 8:56 am ] |
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Would a big fan pointed at the area in question be the way to help in this process? Sam |
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