View Single Post
Old 04-06-2012, 03:07 PM   #101 (permalink)
Sven7
Master EcoModder
 
Sven7's Avatar
 
Join Date: Aug 2011
Location: Warren, MI
Posts: 2,456

Boo Radley - '65 Ford F100
90 day: 13.28 mpg (US)
Thanks: 782
Thanked 669 Times in 411 Posts
I'm going to wager it's increasing drag. The air wouldn't be separating from the roof surface that early, and the spoiler actually ramps up instead of tapering down.

Find someone who owns one without the spoiler, do a tuft test, and see if the air is separating before or after the place where the spoiler is. If it's afterward, the spoiler's probably hurting your FE.

__________________
He gave me a dollar. A blood-soaked dollar.
I cannot get the spot out but it's okay; It still works in the store
  Reply With Quote