Tim Noce

Hi All,

I figured this would have been posted somewhere or at least easily accessible on the web but I am having some difficulties finding any solid info.

I wanted to know if there are any other differences between a 1986.0 and 1986.5 besides the updated "S4" suspension and bigger brakes.

Is the 1986.0 essentially the same as a 1985 or is it the just like a 1986.5 w/o the brakes and suspension?

I am wanting to update Theo's spec sheets for all 928s as it doesnt include the the differences. Just in case anyone is interested, I converted this to an XML Spreadsheet for upload.

Thanks in advance for the help!

Vilhuer

That has been huge work to get everything together. Just quit note that all data isn't correct. Late MY automatic differential has 1.9L oil instead of 3.0L. There were also 8x17 ET52 front wheel option in late GTS. So it could use some work but its very good start.

davek9

There is a thread on here covering this, but in short, the 85 and 86 32v are the same car.

the 86.5 has same engine and trans as the 85/86, you are correct on the S4 suspension and brakes, also need to include the Anti-Lock as standard. The exhaust was also changed to a true dual (doesn't share the same resonator) and so the battery box got smaller to clear the exhaust pipe.

Rob Edwards

Good thread on the differences:

https://rennlist.com/forums/928-foru...lier-86-a.html

PorKen

More:

Late '86.5 have S4 hatch with indents for S4 wing mounting.

'86.5 have an updated LH computer - yellow vs. green motherboard.

All '86 ABS standard, also alarm (both still optional in '85).

'86.5 ABS is changed to weatherproof connectors and has fewer, 45 vs 90, teeth at the wheels.

'86.5 true dual exhaust pipes are also larger diameter, except at the entry pipes into the rear muffler.

JBGold07

My 86.5 has 8" H4 headlights and no chrome trim ring. Canadian car if that means anything.

Avar928

86.5 also has S4-style cam cover bolts and a diverter valve(?) that straps onto the cross bar.

Early '86 has the old hex bolt cam cover bolts and nothing attaches to the cross bar.

davek9

^^^^ I hated that Diverter Valve on the cross bar, I moved it to the Hood switch bracket, much cleaner look and easer to remove the bar when accessing the engine.

And... ALL 85 - 86.5's greatly benefit in performance by changing the stock LH and EZF chips to the PorKen S300's

Avar928

Does the updated LH in 86.5 cars have any performance or functional difference? I'm not really adept on electrical circuitry.

What does that valve do anyways?

Alan

USA cars do not have this.

Alan

BIMMERMIKE

"I hated that Diverter Valve on the cross bar, I moved it to the Hood switch bracket, much cleaner look and easer to remove the bar when accessing the engine."

Do you have a picture showing new location?

PorKen

No?
There is better shielding for the O2 sensor input. (Ground traces on both sides of the voltage input from the connector to the A/D chip.)
The yellow board leaves out the components used for the coding input for automatics (no injector cutoff on decel). Granted, it was never used, or wired in the harness.

Base fuel map has some additions, but it's out of range of where the engine can breathe at.

Landseer

Aluminum mounts for the rear trailing arms, as noted, are also removable (through bolted into the cockpit with plastic covers at the heals of backseat passengers, as opposed to part of the underside unibody on earlier cars.

As Ken has pointed out also, the rear jack points protrude down below the rocker sill and are a dead giveaway when viewed from side.

86.5, to accomodate the split duals, has a shortened battery box.

Front suspension differences include the antisway bar and the downlinks, also the aluminum air guides to cool the brakes are different to allow for the the ABS wiring harness and other suspension changes. WSM details these differences I think.

The ABS brain itself is different version.

Reg 86 and 85 have some differences, like the timing covers on 86 allow you to see the timing marks on gears down through the vent holes without removing them. Tensioner arm has a different offset.

Very early 85 had reversed layout of damper and fuel regulator, and some fuel line routing difs., changed later in MY 85. WSM shows the earlier layout and it has confused folks. See tech notices for new diag.

I read that very very early 85 USA, though I've never seen it, had stickers on radiator showing the wrong numbering sequence for the wires on the distrib caps.

IIRC, Reg 86 got radio noise suppression ground between wiper and body; I think coil body grounds for noise suppression also started in early 86, not 85.

I've got an 86.5 in the garage, just being opened-up as a parts car, if you need other checks made. 85 and 86 are in driveway. Again, for comparisons if needed. Above is all best of recollection.

PorKen

'86.5 get new higher rated smaller S4 battery.

'86.5 also have a higher rear seat 'floor' to fit the big ol' resonators.

FWIW, late '85 have original right and '86 left covers. Early '85 have the diagnostic plug and TPS extension harness plug reversed.

John Speake

The cambelt tensioner arm was modified, this required a new central cover and the dipstick with a bend in it.