The original Fiat X1/9 seemingly had it all, from Buck Rogers styling and four-wheel-independent suspension to a tasty mid-engine layout and a removable targa top. It was sexy, Italian and built for sin.
Unfortunately, the car was also slow. Really slow.
Credit for that lack of speed goes to the times. Back in 1972, when the car was released, the proposed crash standards looked tough to beat. To meet them, Fiat made the X1/9 strong—and that translated into heft. The 1290cc-powered car weighed more than a full ton; do the math.
The X1/9 met these proposed crash standards while others didn’t, but then the standards were changed. This left Fiat with a strong, yet unnecessarily heavy, sports car compared to its competition. Enthusiasts looked for solutions.
Over the years, a number of different horsepower recipes were sampled in the X1/9. Most chefs reached to the Fiat parts bin in order to hot rod the car, though some did look to other car makers for more power. John Soman falls into that second group.
Mother Necessity
Engine swaps are a popular option these days, as replacing a stock engine with something bigger from the same manufacturer is often seen as an easy way to make more power. Want to make a Civic faster? Swap in a larger Acura Integra engine. It’s a simple formula that produces proven results.
Cross pollinating can be a little more difficult, however, and the process can get even hairier when it comes to putting new technology into an older car. Most people who go this second route know what they’re in for. John didn’t. “I had no idea how to do this when I started,” he says. “I had to go buy a welder and a grinder, all that stuff.”
John started out with a decent but non-running 1974 Fiat X1/9 that he bought for $400. He originally intended to install a new, modern engine in it. John knew that something transversely mounted and small in size was needed in order to fit into the rear of the Fiat. He really liked the VW and Audi 1.8-liter turbocharged powerplants due to the availability of parts and the ease of making more power. He also toyed with the idea of using a Toyota engine, as they’re robust and compact. However, he finally decided on his Fiat’s secret weapon—Honda power.
After searching eBay for a few weeks, John found a crashed Acura RSX Type-S that was being parted out. John got the complete engine and transaxle for $2700. The ad said the engine ran, although it had a cracked valve cover; a new one was included with the purchase price. The sale also came with the wiring harness and stock ECU. John jumped at the deal.
“I didn’t know what I was really getting,” he now admits. “I have never bought anything like this over the Internet before. I wasn’t sure if it was the same as the ad said or not. But, fortunately, it was.”
John says he wasn’t sure if everything would fit, but sometimes ignorance can be bliss. He thought he had a rough idea of how things would go together, but didn’t know for sure until the engine arrived and was test-fitted. After that, the real work began.
John had the Fiat completely disassembled for the project, so any required cutting and shaping wasn’t going to be too difficult. However, to his surprise, everything fit once the stock rear trunk was removed.
Electricity, Electricity
While making the engine fit was somewhat easy, making it run took some work. Here John had to mix vintage Italian wiring with aftermarket Honda technology.
The car actually uses two electrical systems. The basic Fiat system runs lights, the horn and other ancillaries, while the engine stuff is kept separate.
John originally thought about running the stock Honda ECU, but some research and advice from others turned him toward Hondata. This company has become the standard when it comes to programmable Honda injection computers. The Hondata boards fit inside the stock housings and work with the original wiring harness.
Once John got the car running, however, it wasn’t fast enough. He started looking for a used Jackson Racing supercharger to give his engine a bit more punch, and purchased one via an Acura RSX online forum.
The Hondata ECU helped John easily get the car up and running once under boost. “I just downloaded a program that could run about seven pounds of boost from their Web site,” John explains. “It was enough to get the car down to the dyno without blowing anything up.”
Once he got the supercharger setup tuned, he still had some troubles getting the power down. He tried using a combination of Fiat four-speed CVs spliced to the Acura’s inner joints, but that didn’t work—the parts just couldn’t deal with the Acura engine’s 270 horsepower, a nearly 200 hp jump over the stock figure. “Bad idea,” John says. “Issues with too much power—sheared axles and broken CVs.”
He finally arrived at a solution with custom Moser axles matched to late X1/9 five-speed outer CVs and Acura inner joints. These axles have held up better under street, autocross and even track use.
Fireworks
Although the Fiat has a stylish shape from the factory, John followed his vision of playing off that basic design and giving the car a modern, racier look. FAZA’s Al Cosentino supplied the fiberglass fenders and rear trunk lid, while the radiator inlet was influenced by the Abarth rally cars.
It’s a fast and striking package, but now that this car is pretty much finished—after a rework of nearly every subsystem—John says he wouldn’t do it again. “This was my first build,” he says. “It got way too involved. I think next time I’ll wait and find a car that is already built.”
