Quote:
Originally Posted by 67-ls1
On an old car, in my case a 1966 Chevelle, with a horrendously shaped underbody, is it better to use an air dam to try to keep the air out or try to fab a belly pan?
I already have an air dam I’ve made for the front so would it be worth it to remove it and smooth the underbody?
The Chevelle is a full framed car with dual exhaust the full length, two relatively huge mufflers, I live rear axle. It’s a mess. It would require a LOT of framing to support it and I’d still have to leave the exhaust area open.
This is more for mpg than downforce.
Opinions?
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GM's two lowest drag cars had full belly pans and no front airdam. Cd 0.137 and Cd 0.14 ( if we ignore the Cd 0.089 Sunraycer ).
A 'guess' for the '66 would be around Cd 0.51.
Today's 'Chevelle' Malibu is around Cd 0.28.
A look under a modern Malibu would say a great deal about GM's strategy for drag reduction over the decades.
HOT ROD Magazine used a full aluminum belly pan on their Cd 0.20, 200-mph Project Red Hat Camaro ( originally around Cd 0.49 ).
There are no low-drag cars without full belly pans.
You're the only one who can make the call on, how much you're willing to invest, time and moneywise.
In one example of a early- 1980s Cd 0.30 car, a full pan with 'slow' diffuser netted a delta- Cd 0.070 drag reduction.