Hot VWs - October 2007 - Project Mileage Motor - Part 10
Testing the unique new Jet-A-Vator




Project Mileage Motor
Part 10: Testing the unique new Jet-A-Vator

BY BRUCE SIMURDA

When we recieved a call from Doug Berg of Gene Berg Enterprises several months back to discuss a new mileage improvement device he had been working on, we were more than a little interested. It seems that Doug had actually started testing a device as far back as 1991 with his grandfather, Glenn Berg, and after his passing a few years later continued work on the project. However, the little device, which fits between the carb base and intake manifold, was not completed until recently.

Named the "Jet-A-Vator", the idea behind this product, according to Doug, is that it, "functions as a restrictor plate, fuel atomizer, and anti-reversion plate. But a basic breakdown of physics is that you never get something for nothing. You have to give a little to get a little. In the original tests, the Jet-A-Vator knocked 10 mph off the top speed, but with a 40% increase in mileage. It was later realized that the 10 mph was not lost, only moved to the bottom end. When the test vehicle went up a 5% grade, it went all the way up in high gears - without having to downshift (as it previously had)."

Definitely an interesting idea, and one we were eager to test. When Doug delivered the plates, which were built to fit our dual Weber ICT carbs, we saw that they were manufactured from aluminum billet, with a specially designed recessed pattern of holes in the center. (Note: details of the Jet-A-Vator are blurred at Doug's request, due to pending design patent.) Two different sizes were provided for the test, one set with a 39% restriction, and the other with 49. Installation was as easy as unbolting the carbs, placing the Jet-A-Vator with new gasket on the manifold with the recess up, and replacing the carbs. Simple installation (longer studs supplied were not required), but could it possibly work?

Before getting into the test, we need to point out a discrepency we discovered this month. Last issue we reported that the carbs came equipped with 130 main jets, but it was discovered that those jets, although stamped #130, were actually drilled closer to 137. This would explain why test #3 last month, with 127.5 mains, resulted in power performance - the drop was much larger than we thought.

For our first test this month, we bolted in the 39% Jet-A-Vator, and retained our 137 main jets and 32: timing. Right away we could tell that the engine was running a little different, as throttle wasn't as "crisp," and the powerband seemed a little flatter. The performance tests confirmed that, as all runs were a bit slower with the Jet-A-Vator installed (but that was to be expected). As Doug said, you've got to give a little to get a little, and at the end of our mileage run we discovered the gain - an increase from 34.95 mpg to 36.49 mpg - a healthy 4.5% increase in mileage by simply bolting it on.

For our next test, everything remained the same, with the exception of increasing the main jets from 137 to 142. According to Doug, the Jet-A-Vator often has the effect of leaning the fuel/air mixture, and adding a little more fuel can help improve mileage. In the performance tests the change was almost unnoticeable, as 1/4-miled times were within a few 1/100. But at the end of the mileage test, we were amazed to see one of the biggest jumps yet - up to a whopping 38.46 miles-per-gallon! With a 10% increase by simply installing the Jet-A-Vator and increasing the main jet size, we were nearly at our goal of 40 mpg. (And remember, that's on today's unleaded pump gas, which contains methanol - which delivers up to 10% less mileage than the premium leaded fuels of the 1980s!)

Excited as the prospect of hitting the 40mpg mark this month, we ran our final test with the 39% Jet-A-Vator, and that was an increase in the timing from 32° advance to 35°. Now, this was an interesting one, because pulling away from the other we could have sworn that the engine was running as strong as ever, and pulled great through the gears. But the performance tests said otherwise, as it was slower across the board. This still gave us hopes for a boost in mileage - but it didn't turn out that way. Without question, our 1745cc engine simply did not like that much ignition timing advance, as mileage actually dropped to 35.09 mpg.

At this point we're going to stop for the month, with a best of 38.46 miles-per-gallon, thanks in large part to a unique new device from Doug Berg called the Jet-A-Vator. We certainly wouldn't have bet the farm on thie invention before testing it, but it sure proved to have potential. And remember, we only tested the 39% restrictor - not the 49%! We'll do a few more jetting and timing changes next month, and wrap things up with fuel injection by the end of 2007. Hey - we may just surpass our goal!