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Old 05-01-2020, 05:04 AM   #26 (permalink)
JulianEdgar
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Quote:
Originally Posted by 67-ls1 View Post
I'm now driving my 66 Chevelle eco project and am getting over 30 mpg.
Im working on a front air dam now and will probably add a small splitter to the bottom of it.
is there any kind or a rear spoiler I could add to the rear of the trunk lid to help airflow off the back?
Either a small wickerbill or a flat extension. Which would be better for economy? I don't need downforce.
And how do I calculate the overall height or length and the fore-aft placement along the trunk lid?
Thanks,
Why not just do some testing?

Is there attached flow on the rear window and trunk? Tuft testing will show you that.

If not, a flat extension spoiler will do nothing. And if not, to gain flow reattachment, you will need to lift the trailing end of the trunk (eg by a raised spoiler or 'wing' (that isn't).

Throttle stop testing (other thread) will also show you if you're managing to get a decent drop in drag (ie above a few percent).
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