From: Brad Orr [showngo@ccinet.ab.ca]
Sent: Sunday, January 02, 2000 6:03 PM
To: 928
Subject: [928] Re: MY differences (TOTAL 928 content!)

At 12:29 PM 1/2/2000 -0800, Dick Mason wrote:
>Is there a place on the net that lists the minor differences in each
>succeeding model year, particularly the S4?  Thanks in advance for any help.
>
>Dick
>85 Black/tan
 
 Phil T.'s website has a quite extensive list of changes to
 model years as the cars evolved. Check:
 
http://www.928s4vr.com/
 
 Since your interest lies primarily in the '87 up S4's, here is
 some related info from a Panorama article written by Kim Crumb.
 This is from the July 1997 issue, and is of course plagiarized
 (although condensed and somewhat disjointedly organized)
 and submitted to the list without anyone's permission...   ;^)
 
 The following are external, visual clues for quick identification:
 
 - 87 & 88 have "windshield impregnated" radio antennas
 - 87 is the first year for 8" wide rear "forged slot" wheels
   mounted with 245/45/16 rubber
 - 89 & up have the sweptback roof antenna
 - 89 GT's have the "one year only" forged Club Sport wheels
   in 8x16 front and 9x16 rear sizes. Tire size same as 87's.
 - 90 & 91 GT's return to a cast wheel in 7.5x16 and 9x16 sizes.
   Wheel is "Design 90" type, visually *similar* to Club Sport.
   These wheels also incorporate RDK system sensors (tire pressure
   warning). Still using 225/50/16 and 245/45/16 rubber.
 - 92-95 GTS models have a different rear bumper cover/taillights.
   They also have the "aero" teardrop-shaped side mirrors.
   Rear wheel openings are "flared" for fitment of larger tires.
 - 92 & 93 GTS models have 17" wheels - 7.5x17 & 9x17 fitted
   with 225/45/17 and 255/40/17 rubber. Wheel style is "C2" 
   type, and RDK sensors are still used.
 - 94 & 95 GTS models have the same wheel/tire sizes, but wheel
   style is "993/Cup" type (cast) and RDK has been discontinued.
 - GTS models have larger brake discs, and the front calipers
   are the Brembo "Big Black" type.
 
 Here are *some* of the mechanical changes:
 
 - 87 introduced a new engine management system incorporating
   a knock sensor.
 - 87 & up S4's have larger valve sizes than the 85/6 four cammers.
 - 87-91 S4's are rated at 316-320hp (depending on source) @
   6000rpm. Compression ratio is 10.0:1
   Engines incorporated special oiling "squirters" directed at the
   undersides of the pistons to reduce temperatures.
 - 87 & up changed to a single disc style of clutch assembly
   replacing the earlier twin-disc type.
 - 88 introduced another change in the engine management system to
   an "adaptive electronic" type.
 - 89 S4 models had revised final drive gear ratio, with a "lower"
   2.54:1 gearset replacing a 2.20:1 ratio
 - 89 GT's had camshaft changes to yield 326-330hp @ 6200rpm, came
   with standard limited slip differential in a 2.72:1 ratio
 - 90 & up models have as standard equipment a limited slip
   differential (PSD)
 - 91 models had no new changes, and 92 models were not imported
   to the US but remained available in the "Rest of World".
 - 92 & up GTS models had the engine displacement increased to
   5.4 liters, with 345-350hp @ 5700rpm and 369 ft-lb of torque.
   Compression ratio was raised to 10.4:1
 - 92 & up GTS models with manual transmissions had a special spraybar
   lubrication system and an integral fluid cooler.
 - 92 & up GTS models with manual transmissions had a rear transaxle
   gear ratio of 2.73:1 while the automatic transmission cars used
   a 2.54:1 ratio.
 - 94 & 95 GTS models had a design change in both the connecting rods
   and piston skirts. These were the first to use forged pistons.
 
 This is in no way a "comprehensive and all-inclusive" list, but will
 provide you with a substantial idea of *most* of the basics. As always,
 I encourage anyone else to suggest additions and/or corrections to any
 of the above info.
 I have not even attempted to venture into the realm of the car's
 "interior" changes. I'll leave that up to DR or someone else
 infinitely more knowledgable.
 And thank you, Mr. Crumb for a great article!
 As well, a special thanks to Philip Katz who faxed me a copy of
 this article back in early 1999.
 
 Brad Orr
 '78 Euro  5 speed
 928 Owners Club