I have an '03 honda civic Si. it looks pretty aero already, but looks can be decieving. I want to make it more aerodynamic so that I have about the same drag at 50 or 60 as I had at 40 before. can anyone give an estimation of the Cd? here be a picture of the car (not mine but its a better picture, mine is about 2" taller from suspension NOT being dropped anymore, mines also white)
here is a nice little drawing with the car as stock (rear wing different)
to start with I am doing a grill block, roughed one out with cardboard but wet slushly snow all the next day, and well, its interesting looking now, and off the car too. here is a picture of the front, not my car again, my plate is in the center above the grill. the whole width will be filled in, and did not get too hot when it was about 30degF out
I also want to make a airdam up front, want to extend it forward as well, to maybe get a little more assurance of the front tires on the ground when I DO go faster.
the first thing I actually did was lower the back of the wing on the car, it looks like it flows nice and smooth, but I dropped the trailing edge about 3-4" and it more follows like a roofline extension.
old wing setup (its adjustable so this was all easy and fast)(this actually IS my car)
new wing setup lowered down to almost roofline extension
I have since applied ductape to help cancel out the vortex generator nature of the wing supports.
the rear bumper is essentiall hollow, and the front under engine is pretty dirty, though the middle of the car is very smooth on the bottom with the exhaust tucked up nicely, so I think some underbody panels up front and in the rear, sealing the rear wheels off from the bumper and smoothing that area out will help greatly, no more parachute, I might even add some ground effects to the rear bumper panel as well, to offset the downforce loss of the wing.
I may do rear wheel skirts, though it looks tough cause the tires come out a little, especially my wide summer tires. if I do this I will be building tire pants as well, including the tire boat tails and spats into the skirts and smoothing it all out. I will likely add some side trim below the car which with the tire spats up front and front tire boattails and rear skirts and front airdam should help to "seal out" the bottom of the car, helping reduce underbody flow and maybe get back even more of that wing's downforce without the aero deficets.
so far thats my plan, I will not be building a kamm back or boat tail, cause I think the rear can be pretty aero once its smoothed out with the bumper and I figure the best rear wing position. also I hate my tailights, so I might pull a mercedes move and duct some underbody or front air to those (dont mind drilling or cutting them at all) to help shape the rear wake a little bit.
I may also do something about the wiperblades, they will stay on since it rains and snows here a LOT, but I may pull a small deflector over them which would cover them completely to the windshield and they would slide up out of it, actually more for snow not clogging them as much for aero (no cold wind a a little heating strip in there and no icy wipers, worth 5mpg to me almost)
I am fortunate because I have an almost unlimited supply of coroplast, since our daycare provider's husband manages a whole bunch of chain convience stores and they just toss those, he said he'd toss them to me if I wanted (I said I was gonna use a bunch for building forts and castles for the kids, which I will though)
right now I am generally getting around 30mpg, with a couple pulse and glide attempts at normal cruising speed getting me up to a high of 42.7mpg. I have also cut off the cold air inlet to my intake, though I dont know that this is helping me yet, just remember its cold here now.