Correct Rear Spoiler Position

[trillizo_y_uno]

Did you guys ever consider the possibility that the spoiler was placed correctly and someone mounted the car backwards???

I'm going to need some help holding on to the spoiler while I rotate the car. What size wrench would that be? I don't think they make 1/2-a-car sizes.

This is not a 1 man DIY job. Too many things could go wrong.

 

[mpbsr]

Did you guys ever consider the possibility that the spoiler was placed correctly and someone mounted the car backwards???

Meaning?

That would explain why his neck is always hurting him as he drives forward looking over his shoulder...lollerz

 

[FRANKREE]

After reading some threads and looking at a lot of mach 1 pics I'm still 50/50 on which way the spoiler should be mounted on the deck lid. In my opinion it looks good either way but I'm wondering which way it came from the factory. I've had my car for about 2 months now.

View attachment 30359

Some 71 - 73 Mustang owners have no idea that they have their spoilers installed backwards. As shown in the diagram above, the spoiler leading (front) edge is the thicker side while the trailing (rear edge) should be the thinner portion of the spoiler. When the spoiler is on correctly, the trimmed off edge (noted by red line in photo below left) will be at the rear. Check yours out!

 

[FRANKREE]

lollerz

So, are you proposing that they pick up the spoiler, turn the car around, and set the spoiler back down? Priceless. ::thumb::

 

[Stanglover]

This has been written and posted about many many times here.
The rear spoiler is in effect a wing, like on an airplane. The thick edge always goes forward. The angle you set it at is up to you. Mine is about equal to the deck angle, 14 degrees as really, it does little to effect the downforce at normal speeds. So mainly for looks.
Also the position of the spoiler on the deck lid is another topic of controversy. I have seen them mounted anywhere from right at the back to the middle of the decklid. On the 429 mustang and Cougar Mgasite, the position shown, thought to be factory, is below. The aftermarket spoiler sold by NPD is about the best repop out there, but their instructions show it mounted 1" further back, i.e. 10 1/2" as opposed to 9 1/2"

 

[Spike Morelli]

I've seen a few of these angled up in back, as if it's a spoiler mounted on a Camaro. Technically, what we have on our '71-'73 cars is a WING. As such, because of it's cross sectional shape, and being mounted upside down, it works just like an airplane wing ( upside down ), so instead of having lift, it creates down force. Spoilers deflect,...... wings create low pressure on the flat side. Now, I can't say just how fast the Mustang has to be going before there is any down force, but it's likely above legal posted speed limits! Those who insist on "angling" the rear wing are probably negating the downforce characteristics of it, and causing more drag, instead of angling it into the direction of airflow.

 

[tony-muscle]

This is a good video of this guy explaining rear wing angle of attack and testing showing that 15 degrees is an optimal balance between downforce and drag. Granted that this is a generic wing but it gives an idea that a little bit of an angle may be beneficial. However, without wind tunnel testing of the whole car is anyone guess. For a fastback wing, a 15 degree angle of attack places the wing horizontal to the road since zero would be following the lines of the trunk lid.

 

[tony-muscle]

Look at the rear wing angle of this picture from Kar Kraft's SCCA Mustang. That angle is pretty steep.

 

[jasonwthompson]

I would not consider a wing and a spoiler the same thing. IMO a spoiler creates up or down force from the air striking against it, like your hand out the window on the highway. A wing creates a zone of low pressure on the curved side, which means that the flat side is high pressure pushing towards the curved side.

 

[trillizo_y_uno]

Did you guys ever consider the possibility that the spoiler was placed correctly and someone mounted the car backwards???

I keep getting notifications of people liking this post. I guess it still makes people chuckle 7 years later.

 

[mrgmhale]

That wing position looks needlessly extreme. I am sure the air flow over the air foil will not be very effective with that angle of attack. That said, the speed of the vehicle needed to get any kind of realistically usable down force from the air oil and/or spoiler is higher than legal speeds on public roads. So, for me the rear wings and front spoilers are really more cosmetic than functional in a practical sense (good enough for me!). All the more reason to put the wing in a flatter position, as opposed to so much rake where the wing is now acting more to add drag to the car needlessly, which would not take a lot of road speed to cause at that steep angle in the photo.