Rear deck/trunk extension instead of Kammback

[California98Civic]

I have been reading some old posts on this site (search function). I came across this post but no satisfactory discussion of it. So I want to repost the statement and start a new thread. A kammback on a coupe like mine tends to undermine visibility and trunk access. Would a truck/deck extension work as an alternative to a kammback? Here's the quote:

"Your cheap fix, is to create a rear deck spoiler which extends rearward,and upward,no steeper than 30-degrees from horizontal,until it intersects the line of the template. That will give you a locked vortex which the air above will skim over as if the car was more like the teardrop. If the spoiler is steeper,you'll start inducing downforce which is induced- drag,and that will cost you at the gas pump."

james

[vskid3]

Have you seen Bonneville flat spoilers? Sounds like the same concept, except the flat spoiler is horizontal or angled down slightly instead of going up.

[California98Civic]

Thanks! Using Bonneville flat spoilers as a search term I found this thread on this site:
Flat Bonneville-type spoiler

EDIT: here's a pick from that thread:
Flat Bonneville-type spoiler