The Subaru X100 is a 100 mpg vehicle that was the brain child of Alex Tremulus. Alex was famous for being the designer of the Tucker car - his character is featured prominately in the Tucker movie produced by Francis Ford Coppola. Alex was a consultant to the Subaru Technical Center (the BRAT logo and side graphics is some of his work), and he was passionate about aerodynamics and fuel ecomony. Walt Biggers, the brilliant godfather of the Tech Center was easily convinced, but more importantly he was able to sell Harvey Lamm, president of Subaru of America, on the idea of building the car. This car had been in Alex's mind for many years and his great idea was to drive the car across the country on one tank of gas to demonstrate the benefit of good aerodynamics on fuel economy and to provide favorable publicity for Subaru at every stop along the way.

Alex's concept was to use a three wheeled vehicle with a extremely aerodynamic body. He was fond of saying that he was commited to "eliminating the sadistic torture of innocent air", and he meant it. He had saved an old aircraft wing tank for many years to be used for the basis of the body on his car. Subaru offered the prospect of a suitable powerplant - a 500cc engine/powertrain package used on FHI's Kei class car in Japan, the Rex. A rear drive unit completely mounted on a subframe with the suspension, it was perfect.

Alex had the concept and a outline drawing of the car but they needed someone who could design and build a real car. Walt asked me (well maybe I asked him) to design the "running gear" for the car. Light weight was important, so I developed a chassis that was light, simple and strong. Because of the limited space in the front, I had to design a unique suspension and steering system to fit. I decided to use the Subaru subframe without modification, so special spun aluminum wheels were made to obtain the required track width. I brought John McCollister, and experienced fabricator, into the team and we built the rolling chassis of the car in my shop.

Alex prepared the body in another shop. He had been the head of Ford's Advanced Styling in the 50's so he was understandably fond of the original Thunderbird, and that's why the body ends in the T'bird taillight. It was always good for a bystander comment.

The proof of the pudding was obtaining 100mpg at Ontario Speedway. A special 1 gallon gas tank was fitted to the car for this so the target was to run for 100 miles, or more. On the initial run, the car ran out of gas 1/2 lap short of the target! So, we made some adjustments to the car and tried again. This time, since physically I'm a bit of a lightweight "myownself", I drove. On this run I made it- the car ran out of gas 1/2 a lap after going 100miles! Mission accomplished, 100mpg. Unfortunately, that was good enough for Harvey Lamm, and the cross country run was never made.

  • This is the rolling chassis of the car.
  • I designed a semi-monocoque chassis for the main part of the car.
  • I designed the forward section was designed to be more flexible to provide for progressive collapse.
  • Alex was pleased when I told him how light the chassis was - 70lbs.
  • The note taped to the rollbar says "For sale or trade for a mini-bike." Those wacky mechanics!
  • The 25 gallon fuel cell is installed here. This was in anticipation of the cross country trip which is a distance of about 2500 miles on the southern route starting at San Diego. It was a major challenge to fit the required volume in the available space.
  • To get the necessary rear track width without the complication of remaking the Suburu subframe, I specified spun aluminum wheels with huge offset.
  • The Subaru Rex powertrain is very compact. I had to design a special linkage to operate the gearchange.
  • The seat cushions are installed in this photo.

  • This is the wood mock-up of the chassis to check the layout.
  • I based this and all of the chassis drawings on Alex's original side view drawing of the car.
  • Fitting everything inside the tubular shape of the wing tank was a challenge - particularly the front suspension.
  • My shop at the time was used as a "skunkworks" to build the chassis and assemble the vehicle.
  • Here's the chassis taking form on the jig. I made all of the drawings for this and the fabricated parts.
  • The chassis was made from steel tubing and aluminum sheet.
  • The available space for the front wheel and suspension was too limited for full size wheel.
  • To solve this problem I designed a hybrid suspension around a smaller sized wheel. The caster was exaggerated to provide a lot of trail to compensate for the small rolling radius.
  • Here's Alex trying on the early build-up for size.
  • Holding the backboard for Alex is John McCollister, ace racecar driver, fabricator and tech who build the rolling chassis.
  • The outer skins of the semi-monocoque are not yet installed.
  • Here's Walt Biggers, godfather of the Subaru Technical Center, trying the car.
  • John McCollister stands nearby.
  • Alex stands by the the main body form which was based on the aircraft wing tank.
  • Some of Alex's admiring associates would say "Alex would put a fin on the back of a turtle!"
  • Alex wanted a curved windshield, no doubt an aerodynamic improvement, but we just couldn't afford it.
  • This is the completion of the 100mpg run at Ontario Speedway.
  • I've just gotten out of the car and an estatic Alex is shaking my hand. Walt Biggers is striding over. A wonderful moment for Alex, and all.

    Here's the article in Automotive News about the record run:

    Contact Ron Jones at 949-637-6067 or