Improving 2008 Focus Sedan Aerodynamics

[mac.mogul]

-Find some 15" steelies and put low rolling resistance tires on them, have your alignment set as close to "0" as possible
-check out the 3dcarbon front lip air dam.
-A belly pan is not recommended unless you are able to design and test it in a wind tunnel... You can make your car dangerous with poorly designed aero.
-Vortex Generators won't do anything on our cars because there's very little low-pressure air coming off of the roof unless you've got a roof spoiler.
-Don't worry about the decklid spoiler. It is just for looks and doesn't have any real effect on aerodynamics.
-If you have access to it, try using ethanol free gasoline. I saw a huge bump in MPG when I switched.
-Lower suspension will decrease the amount of low-pressure air under the car, but if you don't have the proper hardware to correct alignment, you won't realize any gasoline savings.

With cold air you'll need a tune to get the most efficient engine operation possible. I'm not sure that your gasoline savings will translate to the amount of money you'll need to spend on hardware and tuning.

Good choice on the spark plugs though. I also use the AR103's and they are definitely a fuel saver.

[5characters]

slow down


and here is a little bit more on the VG

http://www.mitsubishi-motors.com/cor...004/16E_03.pdf

http://www.focusfanatics.com/forum/showthread.php?t=270062

[emsvitil]

http://autospeed.com/cms/title_Modif...5/article.html

http://autospeed.com/cms/title_Modif...6/article.html

[Montag]

two words: BOAT TAIL

[StockTalon]

Reduce the frontal area, run smaller mirrors, leave the windows and sunroof closed, make fender skirts, etc.

Also, lower the car as much as possible and run a lip spoiler.

[mixadj]

Sorry I haven't been back to this thread lately, I have midterms this week. I have a feeling I am going to have to do some more research on this subject. I might look into building a quick release boat-tail for when I go down the highway. I do have a frontal belly pan but I think it ends right before the transaxle. I was looking at some release notes for the MK II body and it said the mirrors were already designed to be low drag. I will have to look at dropping the vehicle though I do like my current ride height. I will also look into front wheel deflectors and extending the belly pan. Thank you for everyone who chimed in, I will have some reading material for the weekend with all those links. I am actually surprised aerodynamics for the focus has not been threaded before. Maybe it has but just not for the American MK II. I need to go make a friend at the Motorsports lab on campus....

[StockTalon]

Originally Posted by mixadj

Sorry I haven't been back to this thread lately, I have midterms this week. I have a feeling I am going to have to do some more research on this subject. I might look into building a quick release boat-tail for when I go down the highway. I do have a frontal belly pan but I think it ends right before the transaxle. I was looking at some release notes for the MK II body and it said the mirrors were already designed to be low drag. I will have to look at dropping the vehicle though I do like my current ride height. I will also look into front wheel deflectors and extending the belly pan. Thank you for everyone who chimed in, I will have some reading material for the weekend with all those links. I am actually surprised aerodynamics for the focus has not been threaded before. Maybe it has but just not for the American MK II. I need to go make a friend at the Motorsports lab on campus....

I doubt this will be possible but, see if you can get a hold of Andrew Brilliant. He is very good at areo work. His main outlook on the whole concept is downforce but, I'm sure you can learn how things work from what he has to say. Either from, posts, articles or, if you can get a hold of him, what he can teach you.

[crice8]

EcoModder.com
This is where I learned alot on this matter.
I suggest lowering it, 3dcarbon front lip, Lighter flatter wheels with high rolling tires...
But the most effective change would be driving habits. You would yield much better mpgs simply by cutting back 6mph to where the car shifts up but at the lowest rpms..

[Gettysburg150]

Slow down. I average 40+ mpg when I drive at 55 mph and shift at 2000rpm. On a recent trip to Jersey, round trip 420 miles, I averaged 37 mpg at an average speed of 75mph. My mods are FRPP suspension (springs/struts/shocks) and wider 205/60r15 Michelin MXV4 tires set to 37 psi

[emsvitil]

Originally Posted by Gettysburg150

Slow down. I average 40+ mpg when I drive at 55 mph and shift at 2000rpm. On a recent trip to Jersey, round trip 420 miles, I averaged 37 mpg at an average speed of 75mph. My mods are FRPP suspension (springs/struts/shocks) and wider 205/60r15 Michelin MXV4 tires set to 37 psi

Ok...

420 miles / 75 mph = 5.6 hours
420 miles / 55 mph = 7.64 hours

420 miles / 37 mpg = 11.35 gallons
420 miles / 45 mpg = 9.33 gallons


So can either save 2 hours of travel time or 2 gallons of gas.

At $4 per gallon, the 2 hours costs you $8........

How much is 2 hours of your time worth?