[DeTomaso] functional airscoops?

[JDeRyke at aol.com]

There has been some controversy on whether these things actually scoop air 
into the Pantera engine bay. I did an informal test a decade ago by wetting a 
finger and gradually inching the wet end out the barely rolled-down side window 
at around 100 mph. My finger was out nearly 3" before evaporative cooling 
could be felt, indicating a fairly thick boundary layer along the sides of the 
Pantera body. This may be why almost no effect is seen with small tasteful scoops 
in the rear quarter area. A photo study done in Sweden a couple of years ago 
with yarn tufts showed that at speeds below about 100 mph, air came OUT the 
gill-scoops, not into them! 
Underbody airflow is not well understood but it appears that air from the 
front of the car plus that going thru the radiator progresses further aft until 
it gets to the engine bay. Our 'sugar-scoop' style decklid generates a huge 
low-pressure area right at the rear window opening, pulling the underbody air up 
and out at high velocity over the decklid. That underbody air also may go out 
the rear quarter openings, scoops or not.
Above 100 mph, the largest type scoops (called 'elephant-ears') do gather air 
inward. But most high-speed racers have found that unless the ductiing and 
other stuff on & around the carb are not carefully designed, it causes the 
engine to go lean at a time when its alrewady under quite a strain. The results may 
be a fragged motor. So most carbureted cars leave a 2" or so gap between the 
scoop ducting and the carb throat. In most cases, it seems that cool air will 
give a more reliable power boost than ram air does. Maybe at Bonneville, 
but.... Finally, if you still want to mess around with quarter window scoops, be 
aware that the window frames are held in only by gasket friction'. MD once suck
ed a window frame out of the car at well over150 mph during an ORR, and found 
that replacements were kind of pricey. Run some sheet metal screws thru the 
frames if you intend to do high speed testing. Good luck -J Deryke


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