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Old 10-23-2010, 05:25 PM   #3 (permalink)
aerohead
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Aero forum?

Quote:
Originally Posted by JasonG View Post
Well i still need another tank and maybe some (grooaann) ABA testing,but anyway.
I'm a pre OBD diesel so i have to burn 25 gal to get numbers, no scangague here.

I added a full size tool box (pics tomorrow) to my truck when i changed to a 5th wheel and lost the fiberglass cap.
this is the first time in a while i have had a tank with no trailer.
it seems my avg trailerless MPG went fron 17 TO 19 MPG !

Normally:
the air from the top of the cab normally gets caught by the tailgate and rolled towards the cab creating the 'bubble' that guides the air over the tailgate forming a sort of tail.

My theory:
The tool box is rolling the 'bubble' up farther back from the cab. This is both causing the the slope to drop farther back as well as creating a primary shallower angle from the cab to the start of the 'bubble'.

Any thoughts or a nice simulation?
Jason,if you'll move this thread over to the Aero Forum there's a chance that more truck folks will see it and chime in.
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