Jadz928

How many RoW MY78 928's were built before US production started?

AND

How many 928's were build on average per day?
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Here's what I know:

Official production of '78 MY 928 began in May 1977 for RoW cars, and August 1977 for US (& RoW).
-Projekt 928, Brian Long & Erkka Vilhuer

US VIN 928200016 build sticker reads 08/77


US VIN 928200029 build sticker reads 08/77

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Production:

..."Production eventually got under way ... in May 1977. Schedules initially called for a rate of 5 cars a day, rising to 15 in the summer."
-Brian Long
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The Numbers:

Per Master VIN thread:

3785 total RoW & US
Note: Japan number (75) excluded for simplicity
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Important regarding VINs:

US and RoW VINs ran in parallel, meaning there are two parallel serial numbers of each. (parallel serial numbers = oxymoron? )

The difference is in the VIN - 9288100016 RoW & 9288200016 US (difference is the '1' vs. '2' modifier)

This is 9288100016


This is 9288200016


Definitely siblings, but built months apart.
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The Key:

MY78 is interesting because it consists of a total of 15 months (65 weeks) of actual production. This is how:

The remainder of 1977 from May - 8 months (35 weeks)

PLUS

1978 thru July - 7 months (30 weeks)

Note: It's my understanding that Erkka's numbers reflect this 15 month span, were a production changeover occurred in August 1978.
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The Math:

2646 RoW cars produced over 15 months works out to 176 cars/month

Which means:

529 RoW cars were produced thru July 1977, prior to US production startup.

13 weeks (65 working days) works out to 8 cars/day average.

This sounds about right to me, considering early production ramp-up

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1139 US cars produced over 12 months (May/77 thru July/77 removed) works out to 95 cars/month

PLUS

176 cars/month RoW = 271 cars/month, both US & RoW

@ 12 months = 3251 cars total

52 weeks (260 working days) works out to 13 cars/day average.

This sounds right, considering Brian Long mentioned a 15/day production schedule.

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Quick backmath works out closely:

529 RoW + 3251 RoW & US = 3780 total RoW & US MY78.

Compare to Erkka's number of 3785

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Erik's US 1978 #0941 built 05/78 reflects a later May build.

941 plus 95 cars in June plus 95 cars in July equals 1131 total, finished by August production changeover.

Erkka's total US = 1139

Pretty darn close!
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In Summary:

An estimated 529 Euro/RoW 928's were build between May and July 1977, before the first US destination 928 was built.

Production volume averaged 8 928's per day starting out, then ramped-up to 13 per day.

Keep in mind this is an estimate, and my approach as rather linear.
See, there may have been a higher proportion of RoW earlier, then tapered off as US production ramped-up.
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So, if you made it thru my "chicken scratch" .... any thoughts?

Thanks!

Landseer

12 full months of 78 production during 78?

Wouldn't 79 production actually begin during late 78?

Jadz928

Great question!
My guess is no. Not sure when the break occured, and if the break was "sharp or feathered in". May?

In my notes, I have listed April as Porsche MY changeover. Could someone substantiate this?

EDIT: Erkka suggests August for production changeover

Yes. My undertstanding is Erkka seperated '79 volumes from calender year '78. Brian Long and Jorg Austen used calendar year volumes, which skewed MY78.

Using his MY79 volumes and a 12 month production run, they averaged 20 cars/day. '79 was this biggest production volume year for the entire marque.

martinss

I love this kind of detective work. I think you ideally need a sampling of VINs matched to production dates during the 78 model run. Sorry, I don't have one ;-)

Jadz928

Thank man, me too.

I believe this sampling has already occurred. I'm hoping a couple of folks much wiser than myself will chime in....

martinss

Having said that I remembered I recently saw 9288200174 - a real basket case - but snapped the VIN. Strangely, to me at least, it did not appear to have the production date:

Jadz928

That is interesting. I'm pretty well sure Aug '77 is when US production began.

However, a high US VIN/build date sticker would be interesting to see!

Anything over 1000, MY78.

pcar928fan

^^^^^^^
OB YODA!

It was great chatting with you last night Jim! I'll keep you posted on 295 and you check in to W11 for me! BE COOL!

Erik N

1978 #0941 built 05/78
EDIT: VIN sticker is the same as in post #6 (ends in 02, silver color) but it DOES have the build date. Interesting that #0016 has a sticker P/N ending in 03, while later cars end in 02...

Jadz928

You got it James. Just sent them an email now!

Jadz928

Great reference point, Erik. Thanks!

#941 in May '78....

I know #834 was also May '78.

Appears MY78 production went beyond May.

928Shane

I have MY78 338. My vin sticker does not have a date code.

martinss

Here`s a puzzle Jim - the two VIN pics you posted (016 and 029) have black VIN stickers with part no. 928 701 112 03. The silver VIN sticker I posted (0174), with no date, has an earlier part no. 928 701 112 02. I wonder if 928Shane`s without date code is the earlier silver label...

Vilhuer

AFAIK '79 MY production started in 08/78. Model year did almost always change in late summer of previous calendar year. Only exceptions were M718 option US GTS.

Austen book tries to give true model year info but it has many mistakes. Long book and few other sources have calendar year info which is really not useful in determing how many cars were made each model year.

PET information for part changes can be possibly used to give timeline what cars were on production line at same time. For example clutch center shaft and torque tube changed in middle of '78 MY some time in fall of 1977.

92881 00753
92882 00054
92882 09522

Above were last VIN's to use early style setup. If change was done at same time for all markets it can give pretty good idea how many ROW cars were made at the time. Some other part changes have clearly been done at different times for different markets. For example fuel pump and hose related changes do no make sense if they were done at same time.

Landseer

Ahh, so anybody who has access to early documentation & WSB can collect potentially relevant data.....



Some triangulation references from a quick scan of the TSB's.....


NOTE: car 8200054 is mentioned in at least 6 TSB's, meaning it was the beginning car for a series of changes.

This would be best-displayed in a timeline format, perhaps we can do that as we collect more info.