Here’s the scoop on scoops!
Air Scoops for the 73s and 74s
Larry Green and I have been doing some tests on the value of scoops on our VW Things. My tests were done in 1994, when I just cut the wader boxes from a 74 in half. This formed an air scoop that provided a super amount of air flow to the engine. I made air temp & oil temp notations before and after the installation of the scoops. This modification was for my 73. Actually, the air flow coupled with my low compression, (6.8 to 1 ) is too much in the winter months. I block the entrance to the ducts to increase the engine temps during the winter months, as well as pulling the thermostat all the way down. My engine ran at speeds of 65 to 75 mph across the Oregon High Desert on one of our rallies, with the oil temps at 180° to 195°. Of course I was slower than the others on the long grades uphill, but the temps on these 7% grades never got higher than 210*. However, I wasn’t the last getting up there either!
Larry was concerned about taking his Thing on the next years Rallye across the Oregon desert in July, with it still running hotter than he liked. He wanted to keep the look of the 74, with the full wader boxes, so he cut the front of the boxes just enough to catch the air flow coming along the body. He started out with the stock wader box then cut the opening in the front. I hot tanked the boxes to get the original paint off for him. Then we began the installation. We use old beading from the inside of the door pockets to cover the rough metal edges. Prior to putting these scoops on, his engine ran 210°-215° on the level with the air temps at 90°. After installing, (1 hour after the first readings) he ran 185° to 190° degrees.
After having acquired another Thing and restoring it I decided to put air scoops on this one as well. The primary benefit has been the incoming air making a positive air pressure situation in the engine bay. This makes it difficult for hot air off of the exhaust system to infiltrate and pre-heat the air going into the engine fan. This one had a drop of 8-10 degrees. Plus I think they look cool. One negative…….when I spit out my pistachio shells while on a long ride….they get drawn into the engine compartment.
Here’s how we make our scoops:
– Mike Humeston
*See recent articles about compression and ethanol
Article last updated February 14,2015