FAST

FACTS

As successful as the 911 was, Porsche was worried that the 911 concept would run its course before they could offer a successor. To replace the 911 would be harder than replacing the 356 – it had to be evolutionary. The car would have to be advanced enough and, most importantly, look futuristic enough to survive a 15 year production run (just like the 356 and 911 did)
To do this, Porsche essentially had to build what they envision would be a ’90s sports car … in the mid ’70s! This meant full body-colored bumpers for a monochrome look, an all-aluminum water cooled OHC V8, pop-up headlights, and aluminum body panel construction to reduce weight
Even the construction of the engine was ’90s grade tech. The bores were electro-chemically embedded with silicone crystals to reduce friction and wear (again, pre-dating the Nikasil coated cylinder bores of the ’90s). The design was an overhead-cam V8 with a highly oversquare design (a race engine-like 1.2 bore to stroke ratio). Internals consisted of a forged crankshaft, forged rods, and iron-coated aluminum pistons. The water-cooled design was to meet what they predict to be ’90s emissions requirements
The 928 featured Porsche’s highly advanced Weissach axle, a variant of the semi-trailing arm suspension. As cars were getting faster (with better tires) drivers are able to exceed the limits of the suspension, causing tendencies like extreme toe-out in corners, as well as off-throttle oversteer. The team at Porsche set out to design the most advanced suspension layout (at the time) that would counter these issues by automatically self-adjusting itself during a corner. Their solution was the Weissach axle, developed for the 928
The Weissach axle “laid the foundation for modern axle kinematics”, and continued development allowed Porsche to confidently introduce a modernized version of this technology into a 911, specifically the 993
Porsche was the only manufacturer at the time to offer a front engine/rear transaxle sports car (a setup not seen until the arrival of the C5 Corvette – again, ’90s tech). Putting the transmission in the rear allowed for a 51/49 weight distribution. The transmission had no overdrive – 5th gear was direct drive 1:1. In addition, the shifter was a dogleg design, but not for racing purposes – engineers assumed the V8 torque was enough to pull from a stop in 2nd gear, rendering 1st gear for occasional use only
The 928 was one of the first vehicles to use mostly aluminum throughout its entire construction (doors, hood, fenders, engine, etc. The rest of the body was galvanized steel, minus the bumpers). The aluminum panels were stiff enough to withstand 5 MPH impacts without damage. Combined with Porsche’s extensive 26 step paint process, the 928’s body is highly resistant to rust, allowing Porsche to offer a 10 year corrosion warranty on the 928 (many cars of today only have a 7 year corrosion warranty)
Very few alignment shops are equipped to align the 928 correctly. The 928 features special suspension bushings that “set” when the suspension is unloaded (ie, when the car is raised on a lift). When the car is brought back down to rest on its own weight, the ride height will be one inch higher than when you started, and will need to be driven over 100 miles to allow the suspension to “settle” to its normal ride height
The problem is that after raising the car in the air to mount tires, shops will lower the 928 back down on the ground and give it an alignment before allowing the suspension to settle. Performing an alignment with an inch taller ride height will make the car toe out excessively once the suspension settles to the factory specs, resulting in excessive tire wear and unstable handling
The 928 also featured one of the earliest forms of passive rear-wheel steering systems, referred to as Porsche’s Weissach axle (a variant of the semi-trailing arm suspension). The design laid the foundation for modern rear wheel steering – it would automatically self-adjust itself during a corner by inducing rear wheel toe-in
The available 3spd automatic transmission came from Mercedes and was very similar to the transmission found in the S-Class, with a different valve body and tuning. In 1984+ cars gain an extra gear (4spd auto)

Key Model Year Changes:

1978-1982 cars are identifiable by their smooth body lines (no aero) and 4.5L V8s (later cars have 4.7L V8s)
1979 updates:
Battery box is now part of the body, as opposed to an external box mounted to the transaxle. Gearbox shocks are now gone
1980 updates:
Power is increased by 1 hp and 20 lb/ft torque thanks to a half-point compression increase,revised valve timing, repositioned spark plugs (4 mm closer to the combustion chamber center), new sophisticated L-Jetronic injection, and updated emissions equipment (now uses an oxygen sensor and a three-way catalyst)
220 pounds in weight savings thanks to an alumimum torque tube and a hollow (vs solid) front sway bar and transmission mainshaft
The radio can now be optioned with a cassette
First year for these options: rear wiper, headlight washers, 6-way power driver’s seat, and automatic temperature control climate system
New 16″ wheels replace the 15″ phone dials from the previous year
Only year to have the 85 MPH speedo due to U.S mandates
Final year of the 10 digit VIN. The following year (1981) and onward received 17 digit VINs
1981 saw virtually no changes, first year of the 17 digit VIN
1982 cars simply gained an MPG gauge that could display real-time MPG

Specs:

4.5L V8	5spd manual (G28) or 3spd auto (MBenz)
220 hp @ 5500 RPM	265 lb/ft torque @ 4000 RPM
0-60 MPH: 7.5 seconds	Top Speed: 143 MPH
Base Price 1978: $28,500	Base Price 1982: $39,500