Porsche 911 Turbo: What you need to know before you buy

Photograph Courtesy Porsche

[Editor's Note: This article originally appeared in the September 2020 issue of Classic Motorsports.]

Whether you call it the 930, Turbo, Carrera Turbo or 911 Turbo–930 was the chassis code, with the model designation changing by year and market–this car needs little introduction. It’s a 911 with everything: big flares, big tail, big attitude and big power. Road & Track’s 1978 review opens with a simple statement: “Outrageous. Simply outrageous.”

Porsche unveiled a turbocharged version of its 911 at the 1973 Paris Auto Show, with European production of the 911 Turbo starting in March 1975. U.S. imports began the following model year, with the name lengthened to 911 Turbo Carrera. 

The heart of this new beast was the turbocharged engine. Where the standard 911 received a 2.7-liter engine, this one measured an even 3.0 liters. Then add in the turbo itself, with American-market cars rated at 234 horsepower. This new Turbo could reach 60 mph in about 5.0 seconds–beyond scorching for the day. During Road & Track’s test of the original 1976 model, Sam Posey set a Lime Rock Park record for a production car “by a substantial margin.”

Turbocharging was new at the time, and with that boost came lag. And with that lag came some challenging handling. Cue the chatter about the model’s widowmaker status.

The Turbo received a displacement bump to 3.3 liters plus an intercooler starting with the 1978 model year. At the same time, the name was shortened to simply the Porsche Turbo–or, depending on the source, 911 Turbo. 

Porsche would pull the turbo 911 model from its American lineup at the end of 1979, but like so many good things in life–Godzilla, Star Wars movies and the McRib sandwich–it eventually returned. Porsche again offered the original turbo 911 to American consumers for the 1986-’89 model years, with a five-speed transmission finally replacing the four-speed box for that final year. 

Shopping Advice

Lou Verdiales
Aero Dynamics
(386) 304-0380

Proper maintenance dictates frequent oil and filter changes, checking and adjusting valves, and inspecting the Bosch K-Jetronic fuel injection for proper operation on early cars. 

Most of the regular maintenance will have to be completed with the engine out of the car, as many components will be difficult to access. This typical engine-out service should occur every 3000 miles or 12 calendar months. Average time to drop the engine is about 3.5 hours, and mounting it back in the car typically consumes the same amount of time.

Components such as the ignition system, fluid and air hoses, and belts will have shorter service lives than their naturally aspirated siblings due to the extra heat in the engine compartment–up to 40 percent extra. Again, these maintenance items should be addressed during an engine compartment inspection every 12 months.

Exhaust smoke with no other symptoms calls for an inspection for the possibility of failed seals on the turbocharger. You can check by looking for oil in the intake tubing. Unfortunately, turbo failure is fairly common due to poor maintenance. Luckily, removing the turbocharger does not require dropping the engine. After removing the rear bumper, you should have ample room to remove the unit.

The wastegate should be inspected for proper operation to avoid overboost. These cars came from the factory with a fuel pressure safety switch set to activate if the engine experiences anything beyond 0.8 bar of boost. Unfortunately, many owners have bypassed this switch, so you may want to check if it’s operational. If you see readings greater than 0.8 bar on your boost gauge, inspect both the wastegate and fuel pressure safety switch.

Engine compartment perimeter seals must be in good condition. Bad seals can cause overheating in stop-and-go traffic by allowing hot air under the car to rise and then be reingested by the cooling fan and intake.

When considering a 911 Turbo purchase, hire an experienced technician to conduct a thorough inspection, including a leakdown test and a head stud inspection. These steps should help you select the right car.

If you’re in the market for one of these cars, there are basically two avenues you can tread. If you want a more primal Porsche experience, an early car (1975-’79) may be more to your liking than a late car (1986-’89). And of the early cars, a ’78 or ’79 will have a larger-displacement engine, better brakes and an intercooler. However, the later cars may give you a slightly better bang for the buck. The improved HVAC and electrical systems make them more advanced, and on average they sell for about 10 or 15% less than the early cars.

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