Aerodynamic Streamlining Template Overlay for ZX2?

[Tygen1]

Ok, here's a couple pictures:
The first is the Overlay on my car, just want to make sure I have correctly applied it. In addtion I added a red line to represent a 30 degree angle going back to intersect the Overlay. It's quite big!
The second is a "What if". What if we imagined a 15 degree angle down from the top of the rear glass, this is the blue line. What if we imagined a 12 degree angle from the top of the glass, this is the yellow line. The red line is carried over from the overlay. I chose the top of the glass because this is where the angle of the cars shape starts to exceed 15 degrees, the glass's maximum angle is 24 degrees. The reason I added these "what if's" is because it will be difficult to make the red line happen without damaging the car to support that big spoiler. Is is worthwhile to pursue anything shorter?

Additionaly my rear window is fairly well rounded. Check out the dew streaming down the rear window picture and the somewhat top view. This leads me to believe the air is pushing and wraping around the outside third of the window, but not really the middle third of the window. If I put on a spoiler, would it need to be tallest in the middle and taper down towards the outside edges?

Thanks for considering my questions!

[aerohead]

Originally Posted by Tygen1

Ok, here's a couple pictures:
The first is the Overlay on my car, just want to make sure I have correctly applied it. In addtion I added a red line to represent a 30 degree angle going back to intersect the Overlay. It's quite big!
The second is a "What if". What if we imagined a 15 degree angle down from the top of the rear glass, this is the blue line. What if we imagined a 12 degree angle from the top of the glass, this is the yellow line. The red line is carried over from the overlay. I chose the top of the glass because this is where the angle of the cars shape starts to exceed 15 degrees, the glass's maximum angle is 24 degrees. The reason I added these "what if's" is because it will be difficult to make the red line happen without damaging the car to support that big spoiler. Is is worthwhile to pursue anything shorter?

Additionaly my rear window is fairly well rounded. Check out the dew streaming down the rear window picture and the somewhat top view. This leads me to believe the air is pushing and wraping around the outside third of the window, but not really the middle third of the window. If I put on a spoiler, would it need to be tallest in the middle and taper down towards the outside edges?

Thanks for considering my questions!

Tygen1,what you illustrate in your first image is EXACTLY correct! And yes.it's pretty big!
And it looks like rear vision while backing up will be a concern ( probably why modern spoilers are "open."
When GM set the land speed record with the EV-1,the angle measured off the top of the tail,to the top of the roof was 15-degrees.And when viewed from the rear,it's upper surface mimic'd the curvature of the roof,rolling down on each side,so your idea of the taper is A-Okay.
Maybe 15-degrees is a good compromise.

[Tygen1]

Seems I have a project for the weekend.....if I'm ever able to coast down test, then I'll have to attempt to test the difference between the huge spoiler and the 15 degree.

Another question... I presume the center of the spoiler will be the highest and it will taper down to the edge of the trunk lid. Should the taper approximate the taper of the roof line and leave some height at the edge of the trunk, or should it be tapered down to zero hieght at the edge of the trunk.
Which picture do you like better?

[cfg83]

Tygen1 -

I like Figure 1 (the first image).

CarloSW2

[moorecomp]

I like this photoshop from teamzx2.com. A removeable cover over an Elcamino style rear would be awesome. A more square rear edge would probably be better for aero. I so want to do this to my car.

[aerohead]

Originally Posted by Tygen1

Seems I have a project for the weekend.....if I'm ever able to coast down test, then I'll have to attempt to test the difference between the huge spoiler and the 15 degree.

Another question... I presume the center of the spoiler will be the highest and it will taper down to the edge of the trunk lid. Should the taper approximate the taper of the roof line and leave some height at the edge of the trunk, or should it be tapered down to zero hieght at the edge of the trunk.
Which picture do you like better?

You could go either way.I would just try to mimic the curvature of the roof as viewed from behind.
I do believe that "taller" is better in your case and that would mean the the sides would project into space.In that case,you could cap the ends with plates which would project forward blending into the C-pillars along a streamline curvature when viewed from overhead.Kinda like the "bird-bath" spoiler of the Mustang GT of the 1980s.

[Tygen1]

You mean like this one? Yes it does collect water like a bird bath

I got too many cars

As long as it doesn't snow too much this weekend, then I'll do some CAD work.

[Cd]

If you aren't sure what the airflow is doing at the back of the car, you could always do some tuft testing ( We all like tuft testing )

[Cd]

Good luck with your project .

[aerohead]

Originally Posted by Tygen1

You mean like this one? Yes it does collect water like a bird bath

I got too many cars

As long as it doesn't snow too much this weekend, then I'll do some CAD work.

Tygen1 that's it!