I am estimating of modify my car like in the first photo, but I have some doubts.
In middle pic, you can see the upper vision of my car.
The rear window and the back end of car they have a particular shape and, I assume an air flow like red and blue, that I have marked.
Differents angles of two flow in the rear end Is it a possible source of drag?
Can I resolve this problem?
Similar rear end one has it the Bristol Fighter :
but in this car, the two flow : from the flanks and from the rear windows has a minor angle difference .
On original tigra, the uper flanks has angled up by 6°, and roof-spoiler angle is 15°, but the real airflow from central car line minor of 15° because, the rear spoliler deviate upper the flow, consequently, I do not have a total by 21° (6°+15°), of angled flow (cause of cross vortex), but a minor value.
If I create new shape like the first photo, I can put the central flow at 15°, optimum for lowest drag, I go to increase the actuale cross vortex and I create more drag (I think).
have you, of the councils give to me?