Aerodynamics

[drobertson]

I have heard several times that the 71-4 Chargers and RoadRunners/Satellites are more aerodynamic than their predecessors. How much truth is in that statement?

I have thought about it quite a bit, and I can believe it. No vent windows to cause drag, more rounded-off edges, optional chin spoilers (on 71 but can be placed on later years), windshield has more slant, and they're a fastback design.

Does anybody have the numbers? How do they compare?

I'm just trying to learn and understand more about these cars.. - David.

 

[Kern Dog]

Hey David...
The 71 Charger was more slippery than the 68-70 in stock form. Not sure about the Plymouths even though from the front wheels back they were very similar.
The recessed window in the 68-70 Charger was a beautiful design but caused turbulence at race speeds. The open grille was an air scoop too. The Charger 500 was quickly mish-mashed together in early 1968 using 1968 model cars but the model didn't get built as a production car until the 1969 model year began.
The issue of aerodynamics for production cars didn't seem to be of much importance until the late 1970s. Today you can clearly see obvious differences between a 2017 Challenger and a 1970. Look at the things that catch the air and cause drag: Rain drip rails. Tires that are tucked in. Wide panel gaps. Windshield wipers. Wheel opening moldings. Bumpers that stick away from the body. License plates that hang down like buck teeth on an inbred nephew.
The new breed of Challengers have windows pushed out to the edge to reduce turbulence. There are foam seals between the fenders and doors. Rain gutters are built into the roof. I did read that the styling department had trouble though with the grille. They wanted that recessed headlight and grille look the 70-74 models were famous for but that design results in an air scoop much like the 68-70 Charger did. There were compromises made to push the grille forward slightly but the top 1/4 of the headlights were flattened off to give the look of eyebrows over angry eyes. I love the look. The car still is second fiddle to the same year Chargers though for tops speed due to the aero of the car!

 

[Kern Dog]

The Wife and I bought a 2015 Challenger in this color. See what I mean about the grille and headlights?

If you were asking about ways to make your car more aerodynamic , maybe look at the NASCAR versions of the day. Granted, much of what they did was only of benefit at extra-legal speeds. Notice that they never had a "go-wing" like the street versions? I do not like that wing on Mopars! I know that it is part of our history but I have never warmed up to them. Race cars had solid spoilers front and rear, lowered suspensions, rocker panels that were reshaped, larger wheelwells to set the car down over bigger tires, etc.

 

[Dennis H]

71 up B Bodies. Thus the fuselage description.

 

[Kern Dog]

Funny how Chrysler copied GM and others with their designs!
The 66/67 Charger rear half looked like an AMC Marlin from the early 60s.
The 68-70 Charger rear window looked like the 66-67 GM Chevelle.
The 71-74 Charger/Road Runner looked similar to the 68-72 Chevelle/GTO.
Even the Imperial stole the rear styling from the Cadillac Seville!

 

[Kern Dog]

AMC Marlin.
1966 Charger...

 

[Kern Dog]

1966 Chevelle.

 

[drobertson]

Very good observations, Kern. I have been thinking about doing some body modifications to my 73 while it's undergoing surgery. I'd like to make the car more slippery, as I live in wyoming... and most driving is highway driving. Also it'd likely increase top speed, and acceleration slightly.

I don't want to do any super-obvious and unsightly modifications, but shaving the drip rails might be in my future! Windshield wiper are already tucked underneath the hood on 71-4 cars, so that isn't an issue. I also plan on using a 72 front and rear bumper, (they're an inch or two narrower) and I'll notch my 73 front brackets to bring it closer to the body, and use 71-2 rear brackets to tuck the rear.

 

[Kern Dog]

1968 Chevelle. Look at how the 66 was more flat and squared off like the 68-70 B body cars were, then GM went rounded and softer lines like the 71-74 B bodies later looked.

 

[Kern Dog]

Okay, I am taking this topic off the path but....
Look at the Cadillac here, the sloping ridge on the C pillar. Distinctive but also ugly!

 

[Kern Dog]

Okay, my last "off topic" picture:
The 1983 Imperial followed that Cadillac Seville by a few years. Hey, I love the Mopars of old but Chrysler did rip off some designs!

 

[rumblefish360]

At least the Chrysler 5th looked a whole lot better than the Caddy.

 

[Triple Black 73]

There's a lot of truth in that statement. The 68-70 Chargers had the aerodynamics of a brick. The 71-74 Chargers were much slicker through the air but still had the massive front section. The '73-74 Chargers had major changes over the '71-72 in the rear quarter panel for aero to produce a smoother transition of air off the rear. This gives the 73 chargers a slooped rear deck unlike the flatter '71. The 73-74 also has an larger rear section stamped in the decklid rear than the '71-72. This is why 71-72 quarter panels and decklids won't fit on a 73-74. The 71 looks much better in my opinion.

The front chin spoiler is a huge help. I have one on my car. Without it, the front will start to lift at 60 and at 80 the front end will feel like its floating. Anything above 90 is down right scary. With the spoiler on, the front will hunker down the faster you go. I had the car up to 165 once (2.76 gears, 27" tires, 5800 rpm). It was very stable at that speed.

I couldn't find numbers for a 71-74 but the '69 Charger produced 380 pounds of front lift at 115mph and 450 pounds of rear drag. It takes 150hp to over come the rear ward drag. I personally asked Richard Petty about the '73 Charger in 2009. He said the minor changes to aero over the '72 made it one the best handling cars at high speed since the winged cars in '69-70. He drove the '73 Charger until '78 I believe.

 

[drobertson]

The '73-74 Chargers had major changes over the '71-72 in the rear quarter panel for aero to produce a smoother transition of air off the rear. This gives the 73 chargers a slooped rear deck unlike the flatter '71. The 73-74 also has an larger rear section stamped in the decklid rear than the '71-72. This is why 71-72 quarter panels and decklids won't fit on a 73-74. The 71 looks much better in my opinion.

The quarter panels are different, but a 71-2 deck lid will in fact fit a 73-4. I have 71 decklid with the go wing holes, and it fits just fine on my 73. But very cool what Petty had to say! The 73-4 Charger's do have an undeniable racing pedigree!

 

[Photon440]

Do you think the 1968 Plymouth was influenced by the 1967 Rambler Rebel?

 

[mopar 3 B]

Want aerodynamics look at the Chrysler Airflows. Chrysler did some extensive wind tunnel testing after the 68 model year and extended into 73 when they dropped the high oval Winston Cup.
Put a Dayton wing on a 68 Charger and at speed the rear window gets sucked out. Its tail panel was also a big turblance spot.
And to think they use to race with out doors or glass.

 

[Dennis H]

Similar, but at least you could tell them apart. With exception, all today's stuff looks looks the same. Try to find your Uber driver at the airport. Can't tell on from another. All the same.
Designers floated back and forth back in the day. Now the millennials just sit at their computers and play before clearing it with the wind tunnel staff.

 

[Nacho-RT74]

as mentioned 71/72 and 73/74 decklids are the same except for the key cylinder hole ( and 71s being already cut for the wing mounting provision on frame )

the "step up" ilusion on 73/74 is just about an impression due the body line, but is not actually an step up., Just about body line but not the outer profile

71/72 quarters are diff and non interchangeable from 73/74 more related to the height and shape of the quarter glass, than the upper body line

 

[Bruzilla]

Funny how Chrysler copied GM and others with their designs!
The 66/67 Charger rear half looked like an AMC Marlin from the early 60s.
The 68-70 Charger rear window looked like the 66-67 GM Chevelle.
The 71-74 Charger/Road Runner looked similar to the 68-72 Chevelle/GTO.
Even the Imperial stole the rear styling from the Cadillac Seville!

The design of the 71-74 Satellites was largely derived from the cockpit profile of the Boeing 707 and 727 jets.

 

[drobertson]

as mentioned 71/72 and 73/74 decklids are the same except for the key cylinder hole ( and 71s being already cut for the wing mounting provision on frame )

the "step up" ilusion on 73/74 is just about an impression due the body line, but is not actually an step up., Just about body line but not the outer profile

This can also be partially expained due to all 71-4 Chargers using the same trunk gutters, dutchman panel, rear glass, etc.