Ultimate ST thread

Gonbau

I think folks are reacting to overly long, what can be read by some as pedantic, posts that seem to be an endless barrage questioning in the same post. For instance, the response to Matt was two posts that were 60+ lines of text plus pull quotes!

Overall there are some folks here who have owned these cars, some with significant history, and are very aquainted with others... real, not so real and everything in between. It is difficult to come up with hard and fast rules that you seem to be searching for. And ascribing meaning to every detail is a challenge.

I understand that the messages might seem long, but the topic requires it. I started posting these lengthy doubts a few weeks ago when I began to realize that SOME people have intentionally or unintentionally tried to confuse these cars, conflating the S/T vehicles with the M491 ones, which are completely different. Many questions went unanswered, often due to what they call the "pretentiousness" in my words. Pretentiousness that has now led to clarifying that the PURE M491 vehicles (not the ones mentioned by Huhgg, which are the Z-program vehicles from January 14th) were none of them S/T vehicles (this is my belief, and people can believe it if they want). Regarding the "pretentiousness," I understand what you're saying, but I must point out that this so-called pretentiousness is only perceived by those who don't understand what I'm trying to explain or say in my texts.
Until a few days ago, it was not known that the M491 vehicles did not carry the T, (this was not known because it hadn't been demonstrated in documents nor had there been any interest in it...), but I did know. Not by observing the documents that Matteo (and who knows how many others) have, but rather through my own observations, through this so-called pretentiousness, through my questions. What has driven me to write these long texts is knowing that there are people with much more knowledge than me in this forum, people who write "books....". Why haven't these people raised these doubts here? Why has there been an effort to confuse an M491 vehicle, supported by a program developed for that series, with the S/T vehicles that were custom-made for each person and were "unique"? What interest have the "experts" had in this?
Lastly, I have to say that the perception I’m getting from different users on this forum is strange. People I respected and people I didn’t are doing things that seem strange to me, to say the least.... As I said, I will continue here, opening "wounds." Asking questions so that later they can call me "mythical," pretentious.... So that in other posts they can tell me I'm wrong about certain things, only for those comments to disappear without a trace when the truth is proven. And this has also happened in this post... Where have certain responses gone, etc.... That's when one begins to lose respect and starts to write "long texts"... When you realize that even today, "lists" are still being made, things are still being hidden....

PS: Regarding the last paragraph, I understand that many people are involved with these vehicles, either directly or indirectly. I also fully understand that by raising certain doubts or questions, some people might be confused or bothered. However, these are questions coming from someone without knowledge (myself). Therefore, if some of these people are "bothered" by my questions... I believe it's for a reasoned issue and not because of pretentiousness. I fully understand your last sentence... "And ascribing meaning to every detail is a challenge."

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Originally Posted by HughH

That the M471 option was itself a bundle of items including:
· 80% locking limited slip diff (option M220 by itself)
· Tachometer up to 10,000rpm
· 380mm leather steering wheel
· Lightened body design consisting of:
o Attachment points for Sports seat belts
o Reinforcement for assembly of the safety bar
o Front and rear bumpers without horns
o Instead of decorative and rubber strips on the bumpers, Tesa tape on the front and rear bumpers
o Rubber quick-release fasteners for hoods on the front and back
o PORSCHE lettering decal on the back
o Simplified interior:
§ boards; door lock operation; carpet; dashboard;
o PORSCHE lettering decals in place of decorative strips under the doors on the left and right
o Underbody protection and sound insulation mats are not required

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If the M471 was a package that included M220 for 1972, why is M220 not mentioned in the Z-Programm nor the SP, but in the M491 vehicles both the M220 extra and the SP inscription are mentioned? It seems as though in the M491 vehicles, the M471 package, which contains the M220 among other options, was not included.

https://www.early911sregistry.org/fo...3&d=1724678675
https://www.early911sregistry.org/fo...6&d=1724763051

Is there any M491 vehicle that has 'M220' listed as an extra on its specification sheet? Or is it present in all of them without an extra number, simply with the word 'Sperrdifferential
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Hi Baudett,
i constantly read the posts in this thread and personally i find them all interesting and constructive.

If you like, even to make a post to collect information, which otherwise are fragmented and divided into many many interventions, it would be nice to have a technical explanation of what the Z program is and what it contains, similarly for M491.
If you want, if you have time and if you like.
I won't care how long it is, but i'm sure it's absolutely useful...

Finally i thank everyone for the contributions, i really like "Ultimate ST" !!

I would like to talk about the Blast vehicle, specifically regarding the construction of the bumper. Was the bumper made with a stock piece from a 911? As far as I understand, yes, but why is the 'dimple' that is present in the stock pieces absent here if that area didn't receive metalwork?

example:
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Hi Andry, if you check my profile, you can see the specific posts I've made about the topics you mentioned!
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Is anyone in possession of the Aktennotiz referenced in the manufacturing sheets of the Porsche S/T Z-Programm from 16.9.1971?

Number 34 car on the cover of latest Esses, is it just me, or do those front wheels look very skinny? 6’s?

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Number 34 car on the cover of latest Esses, is it just me, or do those front wheels look very skinny? 6’s?

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I believe they were 7R's...

Could very well be you’re right, Chuck. Makes sense

By the way, is this the car called Sloopy Jr?

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By the way, is this the car called Sloopy Jr?

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It is indeed ... ;)

I just read this whole thread...and left a bit confused on a few things.
It seems Hughs posts of 963 and 991 helped put much in perspective.

I then read the 000 article. And remained confused.

How do we define a S/T? For 1972 it seems easier, 1970 more confusing - is it just the 930kg cars for 1970? For 1971 is it the M471 or M491 option that defines it? (There was also some discussion on this thread about a "T" mark on the documents? ) The 000 article states that S/T's are notoriously difficult to define. So what is an S/T or are there multiple definitions, and if so what's the most exclusive one - assuming factory built not built by a customer?

The engine selection was also confusing. I always thought that if one ordered the M471 or M491 options, an appropriate sized competition engine would be installed, which was different than the street S engine. (and I thought from 1971 it would at least be a 2.3 liter). But that seems wrong now.
Looking at the 000 article that has a "likely ST" chart, for 1970 the engines seemed to be all 2.2's with one 2.3, in 1971 almost all are 2.2 with two exceptions, a 2.4 and 2.5, and in 1972 most are 2.5 liter.

Were those 2.2 liter engines the standard S engine - 180 bp 2179 cc engine? A few of the documents on this thread indicate that spec engine, assuming they are ST's. Or were those 2.2 liter engines modified? A letter posted by user _gonbau seems to indicate that one could then ordered a special competition engine, mentioning a 2.3 liter in 1971.

I don't feel so bad after even Barth states that he can't definitely determine if the 000 chart ST's listed are real ST's!

Richard
This is my take on this

I think it might be easier to think of the ST’s, especially for 1970, more as a “concept” rather than a specification of car. They were designed / created to take advantage of the homologation rules and parts that Porsche had homologated for the 911S, in particular, for Groups 3 and 4, both for factory rally cars and for customer cars while the main focus of the racing effort was on 917’s etc and outright wins for major track events. The main homologation documents were 3005 for 1970MY 911S in group 4 (GT) and 3025 for GP3 GT and GP 4 911S. With the main factory focus, and budgets, on the “plastic cars” this allowed Porsche to have a presence in the races via customer cars and the rallies with both factory (probably only because of the successes in 1967 to 1969) and customer cars.

The easiest way for me to think about it is firstly by classifying the cars between factory-built cars and cars that were modified and constructed by customers either using factory kits or just picking and choosing from the homologated parts list. The latter group of cars could be built on any LWB car – ie 1969MY and on and any engine spec shell (T E or S) as the shells were or could be made more-or-less the same as most of the factory-built cars. In this explanation I am ignoring this latter group of cars.

Then you start with the body shell. The 1970MY S forms the basis of the shells. It was homologated as a lightweight road car (to achieve the numbers for GP3) which as homologated (but not as mostly sold) was a car with a stripped out interior and other weight savings measures. Only a small number of those were sold as road cars in that (911S homologation or 911S lightweight) form and even then, it is likely that a lot of those cars that were sold were fitted with some competition options like roll bar, Sperrdifferential etc. I think that these cars, while having a lot in common with ST’s do not pass the bar of being called a ST, unless as an extra modification from the factory such as the engine output was enhanced (which did happen in the customer race department) and perhaps a gearbox with competition ratios was also fitted.

FIA 3005 and 3025 has the weight (total weight of the vehicle with standard equipment in running condition with water oil and tire spare wheel but without fuel and without tools) at 960kg whereas the equivalent number for the 1969 S was 940kg.

In addition, there were a number (unknown but probably up to 50) special lightweight shells made with an extensive amount of thin metal panels. They formed the basis of the so called 930kg “Rallye” cars and were the lighter weight version available to be built up as a competition car. However, many (most?) of the 1970MY cars were destined to be rally cars where (apart from the werks cars) this weight differential was not as important.

On top of that, for Group 4, there were “light weight” and “wide body” options in the homologation papers as well as plastic, light metal (aluminium) and plexiglass parts allowed. This included, but is not limited to Front and rear fenders and hood in plastic, door skins in aluminium, front and rear bumpers in plastic etc.

Once the appropriate body was chosen for a competition car then the engine and other mechanical specs could be chosen from the homologated parts list. For rallying for example an almost stock 2.2 engine (84x66 with 180BHP at 6500RPM) could be the best engine choice and even some of the factory cars has those, especially the rally cars in 1971.

A significant number, but probably not all, cars with 84x66 engines however went to the customer race department to have the output “enhanced”, often with warranties voided, before delivery. These can be identified as having a written notation close to the top RHS of the Kardex signifying that that work has been done but there are no existing records (that I have seen) as to exactly what was changed. Also, the amount that the engine output was enhanced to is not clear and possibly varied between engines given the bespoke nature of the process. However, in earlier years the same process could add 20BHP or so.

At least one 1970 factory rally car (9110300002) has a 2.3L (probably 911/21) engine with 250bhp for Monte Carlo in 1970. That was more a tarmac event than some other rallies. It was based on a 930kg shell but had all the other lightweight bits. It was reputed to weigh 861kg in that form but that was probably dry weight.

The engine options ranged from an almost stock engine probably with some mild tuning to 2247 (85x66) 911/22 engines with 230BHP at 8000 rpm with twin Webers or 911/20 with MFI with the same output and 2380 911/21 engines with 250BHP at 8000RPM with MFI. Finally, the M491 (track)versions had (or could have) 911/70 (86.7x70.4 2494) engines with 275BHP at 8000RPMs.

Those with the GP 4 options, including twin plug heads etc, were more likely for track versions (M491) etc and the milder ones for rally.

It is an open question as to whether ONLY the 20 or so M491 track versions should be called ST’s (at one extreme) or all competition modified cars using the menu of parts in the homologation papers can be called ST’s. The latter is now the more normal definition, I think.

Also it should be remembered that these were competition cars. The original spec was not as important as what enhancements could be made, either in the season they were built in or a subsequent one, if new parts emerged. This makes defining such a concept as a specific specification so difficult especially when most were bespoke builds with the ability to change specs during a season depending on the use in the next event - ie rally to track or vice versa.

However, I am not sure if this answers the original question or confuses the issue even more