Ultimate ST thread

[928cs]

Was this one already discussed here, 9110301046?
https://pbase.com/archive_racing_porsche/n_911_030_1046

[HughH]

That is great information
The Greider car was easy to spot as it always raced with those gold BBS wheel before it was looked after by Kremer with a new owner, i think, in Germany

I had worked out that the other car was the Zibden car 0909 but i was not aware of Blumer racing it
These are the first photos I have seen of it back in the day although I do have photos of it in its current (restored) state

[niall1]

ST/R, ST with Rally spec…?

Quite likely. When I spoke with Richard Reventlow about his trips to the factory to agree the spec and order the parts for what is now my car, he referred to the fender flares as 'Rally arches'. He didn't purchase from a catalogue. His recollection's and descriptions/language used were from meetings with Helmuth Bott when planning the car back in 1972.

[_gonbau]

So, to be direct about this matter, these vehicles from 1972 were issued under the M491 program, a program in which no differentiable options could be included—just the M491 program without any M package, unlike other vehicles. ALL of them were identical. As indicated by the documentation, this leads me to consider one thing: either all M491 vehicles were "ST/R" (which I find very unlikely, but I’m trying to understand it under your explanation)... or these vehicles you refer to as M491 (ST/R) underwent later modifications to be able to carry the ST/Rrally designation you mention.
Considering that in 1972, M491 was a circuit racing configuration and not for rallying, I would have thought the STR designation would be more appropriate for an M471, which could indeed be equipped with any type of M package and, according to the documentation, was suitable for rallying, track, and regular road use.
Having the rear badge of 2.4L might suggest that these vehicles you’re showing were indeed modified somewhere before that event. Lastly, the image you show indicates the SR designation, not ST/R—something important to note since it’s an “old” image, which tells us that SR did indeed exist. Perhaps, back then, ST and SR were terms used to define different vehicles. Maybe the ST was the M471 vehicle from 1972 (or Z-programm), and the SR the M491 vehicle. Perhaps. It will always be interesting to hear the debate on this topic.
FROM MY POINT OF VIEW AND AS AN ADDITION, the ST/R designation is incorrect. I would say the correct designation is SR, which is very different from ST/R.
+
STR was written on the 1971 vehicle on the flare, so I want to ask clearly: are there different people who can confirm they have seen that STR from this forum? I’ve only noticed STR on the 1971 vehicle and now in what Leirbag mentions, so I wonder where else this designation has come from.
What did the "R" in RSR mean?
And why, if we have the information on how M471 and M491 vehicles were issued, do we "invent" the SR designation? We know the ST designation has existed since 1970 and is visible in various construction sheets for those vehicles. As I understand it, neither of these two vehicles from 1972 we are discussing has the S/T designation written on its sheet, much less ST/R. I must assume that on the sheets for these vehicles, only M491 R-ennausfuehrung* appears.
I suppose some people know this because they have access to these sheets, but only that detail. We have the information provided to issue a racing vehicle, we have the designation used to define the Z-program vehicles, with the S/T designation written on their sheets. As far as I know, for M491 vehicles, no such designation exists (only the one that has been attributed to them so far, ST, without even being noted in any construction sheet for those cars).
But if this were correct, then M491 vehicles could be S/T and ST/R, even though Porsche documentation explicitly stated that an M491 vehicle could not compete in rallies. So, from what I understand about "ST/R"... is there any Akkenotiz that mentions this "type" of vehicle apart from the ones shown?
And considering that STR was never a real/written designation... Why, if we know that S/T was indeed used to define "some" vehicles, does STR not appear in any sheet or Akkenotiz so far?

[HughH]

Baudett
Most of the 1972 M491 2.5 cars were used as rally cars both on gravel and tarmac as well as on tracks
these include:
230 0495 at the 1972 Acropolis and other Greek and Turkish rallies in 1972
230 0538 arguably a track car but also at 1972 Targa Florio rally
230 0550 did some track events but mostly a rally car in Scandinavia - mostly gravel
230 0983 seems to have done hill climbs
230 1019 Tour of Spain, Rallye Bosch, Costa de Sol rally, el Ciudad de Oviedo etc
230 1195 Hill climbs
230 0769 E40 Zasada's factory owned car mostly rallies
230 0818 Targa Florio 1972 but more a track car
230 0870 Targa Florio 1972 but more a track car
230 0872 Hill Climbs and Targa Florio 1972

So while they were essentially built to the same spec as a production run, the platform created by this car could be used for a wide range of motorsport events by customer drivers of various skill levels at both top level events down to club events mostly by relatively minor setup changes and addition or subtraction of specific equipment like lights and underbody protection for rallies

[_gonbau]

Thanks for the info, Hugh. I believe I’ve disagreed before, but I still think that Z-Programm vehicles should be separated from purely M491 vehicles and should be considered differently. Based on the documentation provided by Matteo, I know that M491 vehicles were not suitable for rallies, as explicitly stated by Porsche. So, does this mean that all the drivers who used an M491 vehicle for some "type of rally" were making "a little cheat"? Or can this not be considered as such?
I mean, if the driver signed papers and changed parts, etc., was that M491 vehicle fit for rallies and normal road use despite Porsche saying otherwise?
I thought that for an M491 vehicle to be allowed on the streets or rallies, it would need modifications similar to the vehicle that ended up in Switzerland, where bumper guards, the 2.4L badge, etc., were added. I understand this was done to that car to get approval for road use. But in the case of these M491 vehicles that went directly to compete, I don’t see those modifications...

[HughH]

I think that there was more freedom in interpreting road rules for events such as the Targa Florio and the Acropolis rally than there is these days. Also in Spain i think the cars (illegally) used German Zoll plates for long after they were not allowed to so the cars using those were technically unregistered
However for some, especially 0550 it was legally registered in Finland and wore the license plate AAV 911 for almost all of its competition history and well after that
0495 had Stuttgart license plates while at the Acropolis - whether legally or not
It is correct that the factory documentation stated clearly they were not allowed to be road registered as they did not comply with the appropriate regulations but maybe that was more the Porsche lawyers making sure that the company was not liable if something happened while an owner was driving it on a road
Here in Australia there used to be an ex werks 908 short tail road registered and there is at least one 917 road registered in Europe and they certainly would not pass the test

[geneulm]

Targa Florio has always been a debate: is it a race or rally? That said group 4 spec (rules were the same for race and rally) was typically the factory playground for most rallies. Group 3 mostly privateer/field filler. With some true rallies even allowing prototypes (Corsica, tour France etc.). Entrance logs show 906, Matra, even a Ferrari 512! Of course the Targa Florio's winners were prototypes with group 4 making top 10. Bottom line, Porsche didn't set the rules; the organizing bodies did.

For tarmac rallies with good weather, rally-spec was pretty close to full "race spec" for the factories. For Porsche this meant as close to homologated weight as possible, twin plug high butterfly motors etc. for rallies where winning translated into selling cars.

"Street legal" was in the most marginal sense. Cars really only had to pass muster for transit stages that featured little/no law enforcement. There are stories where drivers were pulled over going way in excess of any posted speed limited ... only to be escorted to their destination by the police while clocking similar speeds. Even behind the iron curtain!

If one looked at the ford, opel, bmw, Alpine and other works efforts, you would see much more aggressive interpretations than Porsche. These companies always took it much more seriously.

[Leirbag]

Some cars didn't have a 2.4L badge, most of these cars did.

I don't really know why some vehicles had the 2.4 badge and others didn't, but I suspect it has something to do with homologation.



black grille with 2.4L badge : 0022, 0550, 0769, 0827, 0870, 0872, 0909, 0910, 0921, 0934, 0955, 0983, 0987, 1019, 1155, 1417, 1687

black grille without 2.4L badge : 0041, 0047, 0538, 0818, 0908?, 1195?

[_gonbau]

I apologize for being persistent on this matter, but the vehicles you mentioned, 0550 and 495, were built under the Z-programm and are not "pure" M491 vehicles. Both vehicles, I believe, were delivered on January 14th? Unlike the "pure" M491 vehicles, these two carry the much-discussed S/T inscription, which, in my view, indicates that these vehicles were suitable for rally and circuit use. This program (which combined M471+M491), in my opinion, was the strategy Porsche used to "legally" employ an M491 vehicle under rally or road conditions.
They developed this program specifically for the cars you mentioned, which bear the ST designation. I assume there are other vehicles you could cite that participated in rallies as pure M491 vehicles; those are the ones that, in this context, seem most relevant.

230 0495 at the 1972 Acropolis and other Greek and Turkish rallies in 1972
230 0538 arguably a track car but also at 1972 Targa Florio rally
230 0550 did some track events but mostly a rally car in Scandinavia - mostly gravel
230 0983 seems to have done hill climbs
230 1019 Tour of Spain, Rallye Bosch, Costa de Sol rally, el Ciudad de Oviedo etc
230 1195 Hill climbs
230 0769 E40 Zasada's factory owned car mostly rallies
230 0818 Targa Florio 1972 but more a track car
230 0870 Targa Florio 1972 but more a track car
230 0872 Hill Climbs and Targa Florio 1972

Additionally, in Spain, they used the "Zoll" scheme, allowing these cars to stay on the roads for several months, possibly even a year, which was obviously illegal. As they say, regulations weren't as strict back then. However, it's clear that with certain vehicles, such as the Swiss 1155 and the ones shown by Leirbag, there was an effort to include the rear 2.4L badge. I suppose each country had its own regulations, but internally within Porsche, where the use of an M491 vehicle on public roads had been explicitly prohibited, this differentiation stands out.
This is why I distinguish between Z-programm vehicles (those bearing the S/T inscription) and "pure" M491 vehicles. I believe this program was Porsche's way of enabling the 2.5L engine vehicle for road use.
pd: