Side Air Spoilers on SUV?

[Buddy]

My 2002 4WD V6 Toyota Highlander gets 20-21 mpg, and I have plans that I hope will boost the mpg to 25. At present it has NO roof spoiler. I previously owned a '84 Tercel, and I added an aftermark aluminum spoiler wherein its cant could be adjusted; moreover, the underside of the spoiler was curved. We all know that the airflow at the back of SUVs is a mess and hurts the mpg. What if I had 3 spoilers: one on the roof, and one on each side (near the rear), with adjustable cants? I know it is do-able, but will it result in increased mpg?

[Cd]

Your biggest gains will most likely come from simply changing your driving style ( less idling etc. )
Adding small spoilers to the rear of the vehicle will help a small amount, but only if they keep the airflow attached instead of tripping it into a larger wake.
To see a real improvement, you would need a large Kammback, like the one MetroMpg tested on a full-size van.

[Cd]

I'm not finding the thread that was done on that van that I mentioned.
Sorry

[wyatt]

Minivan Kardboard Kammback boosts MPG +3.7% (6.6%, counting roof rack delete)
This is the one you are thinking of Cd.

[Buddy]

I have had a ScanGuageII on my SUV for years and have perfected hypermileage driving. You wrongly assumed that I don't know how to drive for good gas mileage.

[3-Wheeler]

Originally Posted by Buddy

I have had a ScanGuageII on my SUV for years and have perfected hypermileage driving. You wrongly assumed that I don't know how to drive for good gas mileage.

Hi Buddy,

My driving change occurred in the spring of 2007 when the gas price first hit $3.50 a gallon.

I started driving slower on the backroads, on the way to work. My first increase was on a Cavalier, where the mileage went from 35 mpg or so to a typical 42 mpg, for a gain of roughly 20% .

Next I did the same thing on my motorcycle and saw it's mileage go from 58 mpg to a typical 73 mpg, for a gain of roughly 20%. I get another 2 or 3 mpg by shutting the motor down and coasting when coming to a stop sign. Just before stopping, I pop the clutch and start the motor back up. I can usually do this since I'm running on the backroads, rather than the main highway.

I think Cd was trying to elaborate on this process and may have given a few more details to try and help.

I would certainly try the spoiler/Kammback edging on your vehicle and see how that helps. Even if you get another 2 or 3% gain, it's still worth it when considering just how important our natural resources are.

Jim.