CONCEPTS: The Subaru X-100 was designed to cross the US on a single tank of fuel

One of the big leaps to JNC popularity worldwide came as a result of the 1973 oil embargo. The crisis inspired designers, engineers, and entrepreneurs to think of ways to push the automobile’s fuel efficiency limits. One such person was no less than Alex Tremulis, designer of the Tucker 48, the Gyro-X, and bits and pieces of the Subaru BRAT. With the embargo, the time seemed right for Tremulis to execute an idea he’d long wanted to try: An extremely aerodynamic three-wheeled car. His dream, as he put it, was “eliminating the sadistic torture of innocent air.” With this idea in mind, he approached Subaru of America at their Technical Center in Garden Grove, California.

The meeting resulted in a green light from Harvey Lamm, Subaru of America’s CEO at the time. He envisioned a promotional cross-country tour with publicity stops along the way. The goal was to create a car that could cross the United States on one (relatively) normal tank of fuel. The agreed upon formula was 100 miles per gallon and a 25-gallon tank, in order to complete a 2,500-mile route from California to Florida.

Tremulis designed the exterior, using an old airplane wing tank he’d been saving as the basis for the body. The design and construction of the chassis and drivetrain was handed to Subaru engineer Ron Jones, who in turn brought in a talented fabricator by the name of John McCollister. Walt Biggers, director of Subaru’s Technical Center, oversaw the project.

Jones was directed to use as many off-the-shelf Subaru parts as possible. To that end, he utilized the engine, transmission, and rear suspension from the Rex, a kei jidosha not sold in America. Although aluminum wheels with a custom offset needed to be made in order to fit under the drivetrain under the body, the combination worked like a charm.

Much of the rest of the car was built from scratch by Jones and McCollister, including the frame, shift linkage, front suspension, front wheel, and steering system. To his credit, the chassis weighs only 70 pounds (32 kg)!

One non-Subaru part you may have noticed was the taillight. It’s from a 1955 Ford Thunderbird, one of Tremulis’ favorite designs, and a knowing wink to his time as the head of Ford’s styling studio.

The X-100 was a side project, done in the team’s spare time in Jones’ shop at the Technical Center. As other projects got in the way – development of the BRAT being just one – the X-100 ended up taking six years to complete. The original oil embargo only lasted about six months, so the initial panic had long subsided. Still, the team saw the project through and testing began in August of 1980 at Ontario Motor Speedway in California.

Before a cross-country run could be attempted, the car had to prove it could achieve 100 miles per gallon while cruising at the national speed limit of 55 mph. For the track testing, a 1-gallon tank replaced the original 25-gallon tank.

In initial tests, the car ran out of fuel a frustrating half a lap from the desired goal. Jones, who describes himself as “a bit of a lightweight”, offered to give it a try. He nailed it in one shot, finishing half a lap past the 100-mile goal. Tremulis was on hand to congratulate Jones and the team.

And that’s it. With the embargo in history’s rear-view mirror, Subaru already established in the US, and the 100-mpg goal achieved, the cross-country promotional tour was canceled. The car has remained in Subaru’s storage facilities since that day.

Until just recently, that is. For 2018, the Lane Motor Museum in Nashville, Tennessee held an exhibit celebrating Subaru’s 50 years of being in the American market. Along with 360 variants from the museum’s own collection, Subaru of America loaned a new WRX STi, the very first BRAT, and the almost-forgotten X-100.

The curator for the exhibit was the Lane’s Education Director, Rex Bennett. Out of all the cars in Subaru of America’s History Collection, the X-100 was the example Bennett wanted for displaying in the museum. And how did he learn about it? From this very website, of course:

“While researching the Subaru Heritage collection, I came across the X-100 in a 2013 article on JNC. I knew it would be a great addition to the exhibit; it showcased an innovative and not-often told story about the Subaru Technical Center in the 1970s. I was also thankful to have BRAT Number 1, as a link to Alex Tremulis (the museum has quite a few Tremulis designs), as well as the WRX STi, to show how far Subaru of America had come from its roots in the humble 360. It’s quite a success story.”

After the exhibit ended, the BRAT and WRX STi were shipped back to New Jersey to rejoin the rest of Subaru’s historic collection. But the X-100 was left on loan to Lane for another four years. It is currently on display with other high fuel mileage cars such as a Honda Insight and a Volkswagen XL1.

Somewhere over the past 35 years or so, the graphics on the sides of the nose have been changed, but otherwise, the prototype looks like Ron Jones had just hopped out of it to shake Alex Tremulis’ hand. To see the car in person, it’s fascinating. That it’s on public display, with thanks to Japanese Nostalgic Car and Subaru of America, is something you should take advantage of while it lasts. Who knows, after this, it might be hidden away for another four decades!

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18 Responses to CONCEPTS: The Subaru X-100 was designed to cross the US on a single tank of fuel

  1. Mazluce said:

    Awesome article! I really loved learning about something I didn’t know anything about.

  2. Scotty G said:

    I agree, excellent article! I missed stopping at the Lane last year, but it sounds like I have a couple of years to see this one.

  3. Leon Dixon said:

    Interesting vehicle born from the era of gasoline desperation when a lot of 3-wheelers with strong kinship to motorcycles were on the road. And a lot more were planned or proposed. Thank heaven we weren’t forced to drive them as regular transportation.

    I knew Alex Sarantos Tremulis since at least the early 1970s and have pics of he and I standing together. He used to call me at my office at Mazda in the evenings and we’d talk endlessly about 1950s Detroit concept cars. Fascinating fellow indeed. One of my favorite Tremulis designs was “La Tosca” done while he was at Ford Motor Company.

    As for the tail light on the X-100… maybe it’s the lighting or angle of the photo, but I am really just not seeing 1955 Thunderbird at all. Not even a little. What I DO see is more like a 1957 standard Ford tail light lens (the one without a reverse-gear clear light in the center and a plain solid red domed lens). A 1955 lens would have had a different shape with a cylindrical reflector in the center with a chrome sleeve. Just not what I see here.

    Thanks for the interesting posting and photos.

    • How cool that you enjoyed such a friendship with him!

      You may well be right about the taillight. About a dozen years ago, we had a ’56 Thunderbird (or was it a ’55?). But it didn’t really fit the collection, so it was sold or traded for something more unusual. Any “expertise” we may have had about T-birds left with the car.

      I’ll look into it a bit further. In the meantime, apologies for any error.

      • Leon Dixon said:

        No problem.

        But again, I would say the tail light lens in the X-100 is from a standard 1957 Ford… not necessarily a Thunderbird at all. And the standard tail light was red with a plain domed shape. The deluxe 1957 tail light had a clear reverse-gear light in the center. And 1956 Thunderbird and full-size Ford both had still different tail light lenses… with a larger diameter center reflector sleeved with a fluted chrome bezel.

        Now… since we’re on the genre of weird and unusual 3-wheel cars of the oil crisis era… have you got a Pulse? Or how about a Dale?

        • While we have an extensive collection of 3-wheel cars past and present, the Pulse and Dale are missing from our list. I’ve talked with someone who has driven the Petersen’s Dale, and the review was rather amusing.

          We tried to get an EV1 from GM, but a local university asked for one as well. Since GM didn’t want two EV1s in the same city, neither of us received a car. I suppose the solution made sense to somebody

          I’ve also tried to get a Toyota i-Road to no avail, even though I have friends who are executives at Toyota Japan.

          Say, anyone have a contact that could get us an Elio prototype?

  4. Mark Newton-John said:

    One way to get crazy MPG numbers is to draft (a safe distance away, of course) a semi or other large truck. Got over 30 mpg in the 70s with my Corolla, which then was exceptional.

  5. Giggity said:

    I want to meet the engineer who got its plan-view blueprints approved.

  6. Ant said:

    Very interesting! Had never heard of this one.

    Perhaps what’s most surprising about this is how technology moved on afterwards. That Honda Insight sitting next to it would almost be capable of matching, if not exceeding the Subaru’s 100mpg at 55mph figure and the XL1 beside that potentially even more, albeit aided by some engine-off, all-electric running. And the Insight at least does would do so in the shape of a (relatively) normal car.

    • When running a combination of the the diesel engine and the electric motor, the XL1 is rated at 260 miles per gallon.

      • Ant said:

        Indeed, though only as long as the electricity lasts, after which it’s diesel-only. Still very efficient of course (it’s a light car with a small diesel engine) but I suspect the economy isn’t quite 260mpg on diesel alone. As the previous owner of an Insight I like its simpler approach.

  7. Long Beach Mike said:

    Anyone reading this who is within driving distance of Nashville owes it to themselves to visit the Lane Motor Museum. You must be a big fan of Japanese tin if you are here, and Lane’s excellent collection includes many fascinating cars from the land of the rising sun. In general, the place is gear-head heaven.

  8. John McCollister said:

    Minor Clarifications: Alex’s wing tank served as the buck for the adequately thick Fiberglas body he had made in Ventura. The aluminum rear wheels were Youngblood formed masterpieces, to Ron’s specs. Rex engine/trans was dead stock. I cut first piece of tubing, at Ron’s (secret) shop NEAR Tech Center, in ’79. Ron maintained office at Tech Center, but checked in daily. Walt and Alex were my only “visitors” until after car was rolling.

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