Using this graph to determine the best angle for my type of rear diffuser (which will start just behind the axle)...
Then using this method/formula from aerohead (in another thread)...
Quote:
Originally Posted by aerohead
*You do need to be on a flat level surface
*You should have 300-lbs of ballast in the front seats so the car will have its 'driving' inclination
*Locate the spot where your diffuser will begin
*Measure its elevation above the ground
*Then measure back to where the diffuser will terminate to get your horizontal distance,your 'run.'
*If you have a scientific calculator,you can use the trigonometric function to get your dimension multiplier
*If say,you do use 4-degrees,enter: 4 tan,to get 0.069926.
*If you multiply your 'run' dimension by this value,it will give you your 'rise' at the back of the diffuser for 4-degrees.
*This will be the exact distance above your original starting elevation for the rear of the diffuser,to get your 4-degree slope.  |
I went to my nearby beach spot with the super flat parking lot, and to the flattest spot of it, "checked" with a 4' level (hahaha!)... I loaded up with "
balast" and took these measurements:
I got 7.5 inches clearance for the low part of these reused "mounts" and 9.0 inches if I bolt directly to the axle assembly
The pics are just for illustration, not precise representation of the measures.
I got 28.5" for the short diffuser option and 30" for the longer option (subtract 1" from what's seen in the pic.)
Then I calculated using the method aerohead describes:
4* (tan4)
Times a 28.5" run:
Times a 30" run:
So depending on whether I go with 28.5" or 30" long diffuser run, a 2.098" rise from level at the trailing edge of the diffuser or a 1.99" rise will give me the 4* angle I want. Now I'll look for the best way to attach this before I cut the plastic from the cardboard template.