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Also from Issue 202

  • F.A. Porsche, 1935-2012
  • 1958 550A Spyder: Badly burned car restored
  • 1984 911 Turbo: 700+ hp ethanol conversion
  • 2012 TechArt 991S: First drive
  • 1962 356 Carrera 2000 GS
  • 1970 914
  • 1982 924 Turbo
  • Smart Buy: 1984-86 Carrera
  • ACC InnoDrive: Driving an autonomous Porsche
  • Meet the man who founded IMSA
  • Hydro-Pneumatic
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One especially dear piece destined for the car was a NOS fiberglass S-T bumper. However, the thought of subjecting such a delicate and rare component to street use caused a re-think. Instead, a steel front bumper was modified to duplicate the fiberglass piece’s contours.

The crashed 911S-T that offered up its hood also supplied an original Plexiglas rear window, complete with a sun-cracked factory “2,2” engine decal. The remaining window apertures were filled with Plexiglas. To clarify, new Plexiglas was not cut and used. No, these were NOS windows wrapped in Porsche packaging. This includes the door, front quarter, and rear side windows…all of it NOS!

The next phase was finding a suitable engine. Opportunity came knocking again, this time in the form of an old IMSA race car listed for sale on the web. 30 years earlier, Porsche had supplied a 2.5-liter engine to Andial that somehow made its way into this tired race car. Buy a car to get an engine? Yes, because said engine had components Tom would need to accurately replicate a 2.5-liter S-T engine.

One of those was the engine’s small diameter cooling fan, which minimizes parasitic losses at high rpm. To each side of the fan are small oil lines feeding center-lube camshafts. The distributor is a period 12-terminal Marelli unit. As cool as these bits were, the induction made the used engine a must-have.

Early 911 racing engines used 46-mm Weber carburetors. Later RSRs used slide valve fuel injection. In between came a short-lived system called“high-butterfly.” High-butterfly throttle bodies are similar to the throttle bodies used on regular-production Porsches of the era, but their butterflies

(throttle plates) were positioned at the top of the stacks instead of the bottom. By locating the plates at the big end of the stack, the plate’s profile made up a smaller percentage of the opening for slightly less restriction.Most of these systems had 43-mm bores.Only a tiny number were made with the 41-mm bores that make them correct for an early 911S-T, but the donor engine had them—as well as the correct racing fuel-injection pump.

Some surprises were discovered when the engine was disassembled.The first was half a set of titanium 917 connecting rods. The second was a set of 93-mm pistons, which swelled the displacement to 2.9 liters — a change made when the car’s previous owner began competing at Porsche Owners Club events.

One wouldn’t expect a high-revving endurance racer to use the same oiling system as a production street car, and the S-T doesn’t disappoint. Replication of its

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