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alfundo said:
Thats what I get now without a spoiler. When I was running the stock tire I got 31 - 32.
My dash readout says thats what I'm getting (31.2), but I always check it when I fill up and the dash is a little optimistic.


Pelly I drive fast, but very smooth. Easy up to speed, coasting whenever possible, and very consistent rpms on the highway. Although lately my mpg has gone down, after I realized how good the 2.4 sounds :D
 

· Royal Floor Sweeper
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The spoiler in THEORY should hurt mileage, as a spoiler adds drag to create downforce.
Most spoilers only make ANY downforce above 80 or much higher.
To get ANY lower speed difference, you need one like that on a Formula One car, which has a huge amount of drag. The rake of a race car spoiler is a balance between downforce and drag.

That said . . .
I have my doubts that the spoiler on the xB does anything more than look cool.
So, it is likely near aerodynamically neutral (little drag as possible and probably little downforce of any). Though, I have not examined a Scion xB2 spoiler to look at how the air should flow around it.

Aside:
If you look at many of the spoilers on modern cars, most don't really do much and many of the aftermarket ones are SO badly designed that they function more as a true wing (providing lift) rather that a "wing" spoiler (providing downforce). All a spoiler really actually is is an upside down wing that make "negative lift" pushing into the ground rather than into the air, like an airplane wing.

If a spoiler does anything, it should hurt mileage. Unless, of course, it is not really a spoiler at all . . .
 

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If the spoiler was made of rigid aluminum alloy & considerably wider & more angled, AND if the xB was rear wheel drive, it could actually function as it's supposed too. In my opinion, the xB's spoiler was mainly designed for aesthetics more than aerodynamics, so MPG shouldn't be affected.
 

· Royal Floor Sweeper
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jrl91789 said:
If the spoiler was made of rigid aluminum alloy & considerably wider & more angled, AND if the xB was rear wheel drive, it could actually function as it's supposed too. In my opinion, the xB's spoiler was mainly designed for aesthetics more than aerodynamics, so MPG shouldn't be affected.
THAT is why I am assuming it is as aerodynamically neutral as possible . . .
 

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I have kinda asumed it was looks only. I never bought it for function I just felt the over all look of the xb was much better with the spoiler. Now the spoiler I have now may actually do something as it swoops up at the end. Although I kinda feel that the hole in the front is what negates any possability for actually working. Still its FWD so a spoiler is usless other then looks anyways.
 

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jrl91789 said:
If the spoiler was made of rigid aluminum alloy & considerably wider & more angled, AND if the xB was rear wheel drive, it could actually function as it's supposed too. In my opinion, the xB's spoiler was mainly designed for aesthetics more than aerodynamics, so MPG shouldn't be affected.
Indications are the purpose of the "spoiler" is only to help keep the rear window clear. This is true for most vehicle "spoiler"s out there, so don't expect any serious downforce or MPG impacts -- not going to happen :)! I've had a "spoiler" since day one and I get about 28mpg calculated including zero highway miles. On the other hand, my rear window stays nice and clear! Works for me :)!
 

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Discussion Starter · #16 ·
Damn, I lost track of this thread. Some great input guys. TJ, kind of what I was thinking. Anyone see the mythbusters episode where they did the differences between a pickup with the tailgate up and the tailgate down? The pickup with the tailgate up got the better mileage due to the fact that the wind current created a push effect.
 

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My xB2 does not have a spoiler, and I only drive in the city (Las Vegas). I get (according to the display) 25.5 miles per gallon.
 
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