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Posted by: gord Oct 7 2022, 06:33 AM

Can anyone offer some guidance for retrofitting floor-pan air deflectors on a 72?

I realize I need to drill 4 holes to attach each one, but do I need to tap the holes? Or do the screws go in from the top and thread in the plastic?

A good description would go a long way!

Posted by: bdstone914 Oct 7 2022, 08:48 AM

Tapping is not needed. They screw into the plastic. There are three holes in each flap.

Posted by: Mikey914 Oct 7 2022, 09:37 AM

Cary RIP did a nice detail on these when I offered a GB Post 81 http://www.914world.com/bbs2/index.php?showtopic=317641&hl=Air%20deflectors&st=75


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Posted by: mlindner Oct 7 2022, 09:54 AM

Just use through bolts with nylock nuts. Mark

Posted by: ClayPerrine Oct 7 2022, 10:29 AM

I always wondered if a rubber air deflector all the way across the car would help with the airflow through the engine.....

Posted by: gord Oct 7 2022, 12:31 PM

Thanks, this was exactly what I needed to know!

Posted by: mlindner Oct 7 2022, 01:37 PM

Clay I also wondered about a full deflector. Maybe just where the deflectors are by the cylinder banks suck more air in from both sides and center to create more of a vortex of some kind cooling more?. But they work.

Posted by: Superhawk996 Oct 7 2022, 02:20 PM

Here’s one way to look at this.

OEMs tend toward optimization. If you didn’t need them - they wouldn’t be there at all. If a full width deflector made a significant difference for engine temps or durability beyond the two that are there - it would probably be full width.

Easy enough to do back to back testing if you want to see experiment to see if it would affect engine cooling.

Posted by: Mikey914 Oct 7 2022, 09:37 PM

My modeling suggested that there is more airflow disruption using 2. 4 edges effectively.
This creates 2 low pressure areas. Mixes better than 1 unless you go down further. Not enough clearance to really do that. They made a really good design. The only improvement we could make was to add "winglets" on ours.