Vilhuer

OK. Lets gather more similar stuff in here. There are more questions than answers really though and some are related to last S4/GT already.

- When speedometer pickup was changed from gearbox magnet to ABS sensors? It was most likely towards the end of '90 MY. Factory documentation says it was at beginning of '91 MY but there is contradicting evidence that it was actually done already in last '90 MY cars.

- Seems what I have though to be GTS heads are actually '91 MY S4/GT heads according to PET. There are differences in exhaust side of the head to allow better coolant flow. These are fisrt mentioned in '92 MY GTS yearly change document but actual change date is vague in it. PET says all '91 MY engines should have these. Change must have been made so late that info was left out from '91 MY changes document.

- For what were more aerodynamic mirrors, which are generally known today as Cup mirrors, designed for? Where they first featured in 911 Cup cars as name suggests or in GTS, 968 or other protos?

- When did GTS production start? Factory paperwork indicates it would be 08/1991 for ROW cars at least but it is extremely difficult to find GTS which were first registered before December '91. Was also ROW production started already after '91 summer vacation or did it start much later in '91? If later what was the reason for delay?

- If US production started in reality after January 1st '92 like it seems, what silver car is featured in '92 MY brochure? Brochure was printed already in later half of '91 calendar year and car featured in it has all US model features.

- Engine oil level measurement was changed so that it monitors level also during time when engine is running. Previously it wasn't monitored so thoroughly. From '92 MY model yearly changes document:
Up to the present, the oil level switch used for monitoring of the oil level was only checked with the engine stationary. With the engine running, the engine oil is circulated throughout the entire lubrication circuit so that precise measurements of the oil level are not possible in this mode. These characteristics are now used to check the oil level monitor:
The switching state of the switch is now also inquired with the engine running, depending both on speed and time.
If no change of the switching state occurs within a predetermined span of time, the warning “Check oil level” is displayed.
If it is found that the oil level is o.k., the operation of the oil level switch must be checked. Two faults may cause the “Check oil level” warning to be displayed:
- oil level too low, or
- oil level switch or signal path faulty
The mileage covered is stored in the instrument cluster for both causes.

- The ABS pulses of the left-hand rear wheel are used as input for the odometer. Late '90 and all '91 MY cars used the pulses generated by the front wheels.

- Yearly change document says intensive cleaning system and the passenger side control for unlocking the rear hatch have been discontinued. I think I have seen '92 ROW GTS which had intensive washer system. Need to check if that is true or not. Mine doesn't have it though.

- Automatic gearbox differential oil capasity was reduced to 1.9 liter by lowering filler plug 35mm. Change was done to lower oil temp and foaming. This also meant heat shield mounted to diff end plate was modified to allow access to the plug. Only other change in diff was different friction plates into PSD. It could be safe to run '90-91 MY S4 diffs also with less oil and to make them run cooler.

- At least some early '92 MY manual GTS engines seem to have different crank damper than what factory literature say they should have. Color is same black as in GT engine but design is different.

- Did manual GTS production start later than automatics? My car is 350th '92 MY ROW GTS if first VIN is 0061. It was first registered in March '92. Its engine is 5th engine for manual GTS and gearbox 68th. 68th gearbox sounds reasonable but engine number is low for such late car within MY. Ludvigsen book says there were problems at Getrag in 6 speed manual development. Porsche had ordered new 6sp design from them but for some reason they could not deliver good enough gearbox. 5sp GTS box we now know was then quickly put together. Did this cause delay when manual gearbox production started?

- For '93 MY, piston and piston ring design was changed. Piston skirt were reinforced in the skirt area. The piston rings for the first groove are designed as taper faced rings, and the ring angles to the contact surface of the cylinder have been changed.

- For '94 MY, connecting rods were changed to stronger design, RDK system deleted, pollen filter added and automatic gearbox cars got dynamic kickdown.

- Did factory actually do special model in '95 MY like they made brochure for? It says it has X38 option wider front fenders made out of steel and 8" wide front wheel and is only available with automatic gearbox, Iris blue metallic and Amazon green metallic color with Classic grey full leather interior. Where these made, where they were sold (at least in Germany I presume as brochure is in German language), how many were made etc?

- Was there larger power option in late GTS production? There have been reports of an optional 360 hp engine in '95 ROW GTS at least. Whats the difference compared to normal engine, what was option code for it if such option existed?

- Based on VIN of the last 5sp made it seems it was done months before actual production ended. What was the reason for this? No more 5sp orders, factory run out of gearboxes or other parts and didn't want to make more?

- As second to last US model GTS is 5sp does this mean that also last '95 US, the Pearlglanz automatic, was made months before ROW production ended or was there gap between when these two cars were made?

heinrich

dynamic kickdown - my early 94 has no pollen filter, I wonder if it has the stronger rods and kickdown...

Vilhuer

19 early '94 US models with M718 are exact same as '93 MY ROW in this regard. This meaning also ROW cars made is spring '93 would need to have those. Which is unlikely.

Cheburator

It's a 1990 GT and the box is not for sale. The only knackered thing on it is the crown wheel... The rest is fine and I need spares for my race car project...

H2

Erkka,

You have a serious case of 928-itis to have made note of all those GTS trivia bits. I've always wondered what it would be like to have a photographic memory.

Difference between '85S (US) and '86.5? Brakes or something like that.

H2

Vilhuer

Have had serious 928 problem since early eighties which got worse and worse as S4, GT and GTS came along. Owning one isn't solution. It only escalates the problem.

US '85 vs '86.5 = entirely new front suspension, different lower suspension arm mounting to body at rear, new brakes, changed real lift points in body, different exhaust, ABS as standard IIRR and several other more minor changes. Some of which were done at beginning of '86 MY.

Every few years there were a lot of changes which by most part do not show on outside. Usually change is for better but not always like deleting TT front flex plate circlip and washers in '86 MY.

H2

Erkka,

You could write a 928 booklet and I'd buy it!

Harvey

Vilhuer

No you wouldn't, you haven't seen the price.

marton

& the twin turbo Cheyenne?

Marton

heinrich

He meant at the time.

Auto-Didakt

I know of another GTS box in Germany with very low kms on it...
here is one aswell:
search in german hebay for seller: Gebrauchte Autoteile Schiffi´s Shop
it only has 64000km's according to the guy

marton

heinrich wrote
well that is a pointless point; almost every porsche model had the most powerfull motor ever until a couple of months later...

marton

928ntslow

LOL..yea, but the POINT is, it was a 928 GTS!

heinrich

I don't agree. At the time the 928 GTS rolled off production there was no other production Porsche with as much displacement, and never after UNTIL the SUV. And that was what -- 10 years later? There still is no Porsche sportscar with that large a displacement.