'86 928S or 86.5?
05-09-2010, 11:44 AM
#31
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In reality '86.5 US model do not have S4 front brakes. All ROW '86 have '86 MY brakes which are different but close to similar as first version of S4 brakes and totally different than earlier S model brakes. All markets except US and Saudi Arabia got yet again different front brakes at beginning of S4 production while US got them in middle of '87 MY. Up to that point early US S4 used same brakes as all ROW '86 cars including '86.5 US models. One of the pistons sizes has 2mm different diameter.
05-09-2010, 11:51 AM
#32
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The early brakes are a known weak point, but the S brakes are excellent. I worked them pretty hard yesterday and had zero trouble, solid pedal and fade free, pulled up nice and strong...and I tend to brake late and hard. I have new pads, new rotors, new lines and rebuilt calipers, so they are working at their best. Don't knock the S brakes, they are very good on a street car. If you have issues they are either not in top condition, or you need to be on the track.
For track work, yes the S4 brakes are definitely a good upgrade. But if I was upgrading my brakes it wouldn't be S4...I'd go GTS/Big Reds at a minimum.
For track work, yes the S4 brakes are definitely a good upgrade. But if I was upgrading my brakes it wouldn't be S4...I'd go GTS/Big Reds at a minimum.
I am not sure if he has even heard of the super speeder law, and if he has, he laughs at it.
475hp/460lb.ft
05-09-2010, 01:04 PM
#34
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Timing belt covers are different early 86 than 85 also.
86 has built-in indicators in the vent holes, 85 doesn't.
My early 86 also has the later TB tensioner.
It is not clear from the technical documentation when in 86 the changeover on some of the minor components was made.
86 has built-in indicators in the vent holes, 85 doesn't.
My early 86 also has the later TB tensioner.
It is not clear from the technical documentation when in 86 the changeover on some of the minor components was made.
My late '85 has updated 5-8 side upper and center timing belt covers (where you don't have to unbolt the alt/PS cassette to remove the cover) but an old style 1-4 cover. It has updated camshaft gears with the front indent to go with the later covers, but the gears don't have the three small holes (one of which lines up with a boss in the rear cover at TDC#1 on the 5-8 side).
05-09-2010, 01:50 PM
#35
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This is true. Technically, S4-up have '86.5/ROW '86 4-pot brakes. 
'85 is the real technological tour-de-force! 5 liter, 4-cam, 4-valve engine, digital fuel and ignition brains, larger dual cats, modern fuse panel, new seats, new beefier transmissions, 115A alternator, wire harness includes ABS/alarm built in (although they still optional in '85), rear air, window relay with key off operation, new gauges, windshield antenna...
The '85 Information book is twice the size (133 pgs + wiring) of the '86 book (64 pgs).
'85 is the real technological tour-de-force! 5 liter, 4-cam, 4-valve engine, digital fuel and ignition brains, larger dual cats, modern fuse panel, new seats, new beefier transmissions, 115A alternator, wire harness includes ABS/alarm built in (although they still optional in '85), rear air, window relay with key off operation, new gauges, windshield antenna...
The '85 Information book is twice the size (133 pgs + wiring) of the '86 book (64 pgs).
05-09-2010, 04:08 PM
#37
