New Swift aero mods
 

Hello,
I have a Suzuki Swift with a 0.32 drag coeficient and i want to do some aero mods. I've lowered it by about 1inch. But from what i've read here the major problem is the back of the car. The problem is that all of the rear spoilers mounted at the edge of the roof are pointed upwords, so will increase drag. But there is a genuine spoiler mounted at the middle of the back, is it helping or is just for look?
I live in Romania, Europe, and here the fuel is pretty expensive.... around 1.1$ per litre.

The middle spoiler is in a dead zone so it won't have any effect.

What you can do is use some kind of plastic material (don't know what is available in Romania), to cover the openings for the fog lights

Thanks. Then for the begining i will smooth the fog lights and block the upper grille..

I'd bet a dollar that middle spoiler is doing something... watch the rear 1/4 panels... the tops sweep right into it, and chances are, the flow hasn't detached at that point, so it's making contact w/ the duckbill.

How much or little effect it has is hard to determine, but I can almost guarantee that it's catching flow off the rear 1/4's.

Those are nice looking cars btw. Nice clean styling. It's like a more modern looking Mini

Here is a full view of the back of the car. When it's raining the back window is getting full of dirty water (from the road) very fast while i'm moving. I think that the spoiler is changing something with the flow who comes from the car and stayed attached to the back.

Ah, sweet, you've got one of the pretty Swifts! How do you like it thus far? Also, welcome to ecomodder!

Well the car is very fun to drive and the 1.5 engine is very good. The average fuel economy is around 32mpg (i've converted from L/100km) calculated in 15k km. But we don't have the roads to drive very economic, 99% of the road is just 2 lane with high traffic.
Here are some pic's of before and after i've lowered the car.

I have blocked the upper grille and it seems like it is a improvement of around 2mpg, still testing.
I want to change the side mirrors because i think they are making a big drag by the noise they make at around 70mph and upper. I found 2 types of aero mirrors but i need some opinion on which is better. Here are the stock side mirrors and the aero ones:

Your guess is as good as mine as to which is actually better... though just going by what I see, and (pretend to) know, the last picture is going to be the best, it has less advertised area (frontal area).

The second picture looks nice, but I'm afraid that's all... the big hole near the door just creates a "funnel" effect, which is good for making noise right next to your ear, as the outrushing air expands back into the air stream. That hole will probably penalize you if anything, so I'd stay away from mirrors (or anything) that create another point for flow to split into more than one pattern.

There's my 1/50 of a dollar... at least I think I'm right...