Many dream of a turbo six. David Chapman actually built one.

By Steve Martin, republished with permission from the July 2015 issue of Fourteener Motoring Magazine

What’s your 914 dream? If your like everyone else it probably involves a clean 914 and a turbo-charged Porsche engine. While it is a tempting dream, few could even imagine attempting the job of putting a 935 engine in a 914. David Chapman actually did it.

But we are getting ahead of ourselves. David has been building big-motor 914s for many years. In the 1970s, just after high school, he purchased a 1973 914, and had the original 2.0 liter engine built into a 2.9 big-valve screamer. The car later blew up after about 5,000 great miles, while doing a burnout. But, it was great while it lasted. And David’s penchant for big motors continued to burn strong.

Over the years, David has had five 914s. But it is the orange 1973 that is the car that we have all dreamed about. He purchased the 914 as a stripped roller in San Diego, complete with full roll cage, 944 turbo brakes, and stripped interior and other non-racing equipment. The 914 had also previously been converted to a six, with original six parts. 

As nice as the car is, it is the powerplant that is the main attraction. To power this beast, David chose a 1979 911 SC 3.0 CIS engine. He drove the 914 with the stock 3.0 engine for a number of years. But eventually he wanted more performance. At the time, the car also needed a paint job. So, David put it up for a vote on 914world: New Paint Job or Turbo the engine. You know what won: Turbo it was. And so the research began. A number of people from both 914world and the Pelican Parts Forums helped with the project.

He started with a BAE aftermarket turbo kit. David mounted the turbo in the rear of the car with a crossover pipe and wastegate. It was a non-intercooled setup that he ran at 8 – 9 lbs. of boost with 8:1 compression. He was hooked. It was what he always “wished the Porsche factory would have done to the 914,” David says. After a number of years with the setup, however, he snapped an intermediate shaft after the oil pump seized.

Not one to stop upping the ante, David decided to “do it right,” as he puts it. His goal was to build an engine reminiscent of the early IMSA powerplants, that often produce up to 700 horsepower. Henry at Supertec in California helped source the parts. Matt Johnson at Johnsons Autsports performed the machining on the twin plug heads, and built the engine. The fuel distributer and intake are from a 1986 930 RUFF euro. David also fabricated an intercooler into the system.

This time around he decided to paint the car and refurbish the interior. Rick Olah (aka Alien) of Area 51 Works helped get the car ready, and Dave Larson of Minnetonka Autobody shot the paint. After nearly 40 years of 914 enthusiasm, David had finally built his dream car: a 914-6 Turbo Carrera.