Factory S/T questions needed for build

[letsrollbabe]

Tom:

Kremer's next line in that text refers to his work with Schrick cams for the 3.0RSR engine, so I think he was just recalling development features that the Kremer brothers led the way on that were later used by the factory.

It is interesting that he says he was the first person to put coil springs on a 911....not an RSR. Maybe he was referring to his STs. But I still stick to my point that even if they were using coil springs, they were not reinforcing the shock mounts on the most competitive ST in 72 ( green 72 Krermer car). It could be that at the Paul Ricard track, Singer was copying Kremer's use of springs on a 911 by putting them on the RSR being tested.

Gib

[letsrollbabe]

Gib


Factory werks R cars had these modifications earlier than 73-i am not sure what documentation was used to arrive at the conclusion that it is the coilovers that required these modification-albeit if that is the assumption then one has to figure out when that was first tested.I am also not sure that kremer is the basis for what the factory did. There are other ST's which the factory modified. What the werks dept performed did not necessarily have to correspond with what kremer did and visa vera.For example factory used S chassis for their mods and not T's and some of the factory ST's were lighter than the customer T's-because the factory had access to thinner guage chassis lighter than even the T's and ran out of this chassis sometime in 72.The latest that Zasada's car could have had this modification is Aug 1972.

Raj

Raj:
I am not trying to imply that only Kremer came up with good ideas for improving the 911 for racing, but they did make some contributions. I read somewhere that the use of coil over springs on track cars really stressed the cross member and caused a lot of movement, and that is why the shock mounts and member were reinforced...but I can't find the source right now.

Paul Frere's Porsche 911 Story says that prior to 1970, sporting regulations allowed homologation of different engines to the same body shell, and Porsche homologated the 911T with the S engine in a light weight version that had simplified interior trim, no sound proofing, sport seats, and lightened front bumper w/o weights to get to 923 kg w/o fuel (2038 lb). A racing engine was avalialbe for 911 T and S similar to the 906 but with the smaller stock S valves, and with a 906 cam and 40 Webers. Interestingly, only the 911T was homologated with titanium rods, and offered as an option. The T came without sway bars, which did not need to be homologated. So they were added by owners, but the weight advantage could be used for reductions in other areas. I think this period is the beginning of the internal designation of 'ST', which stuck to these cars.

According to Frere, beginning in 1970, all factory "competition cars were built on the basis of the 911S" (as Raj says). Edmond Harris says that Kremer and the factory both used the 911T as the basis for 'STs', but not sure what he means by that or why the factory would do this if there was no homologation advantage of the T over the S. Maybe Hugh, John Starkey, or others would know more details of factory methods for the STs.

Maybe strengthening methods were used by the factory for rally cars, but not for track cars up to 72. The factory was not racing the 911 STs, leaving that task up to Kremer, Strahle, etc. But they were very interested in winning rally events, so maybe they did reinforcements for these abused rally cars to help them stand up to the punishment.

[letsrollbabe]

Raj:

Some really great pics showing various versions of reinforcements employed. The Samson car does appear to have some layer of bracing welded into the corner where the cross member meets the boxed channel, but no shock mount gussets. The Brumos 59 that won Daytona 73 was a factory prepared car and it most likely had coil springs, and could have had the extra bracing. The Penske Sunoco 6 car would have had it too as a sister car to the Brumos livery. Both ran as a prototypes because the coil springs were not homologated (also the larger rear bearings, etc).

I think beginning with the 72 body shells, the shock mount cone was a larger diameter and can easily be converted to coil springs today. Not sure about what springs were available back in the day.

[letsrollbabe]

Raj:

Yes, I agree that some fitting and work had to be done prior to Dec. 72 at Paul Ricard. In an article in April, 97 Excellence John Starkey quotes Singer: "...We had, in 1972, a test at Paul Ricard circuit and this was the point where we started to install coil springs which were allowed in Group 4. Lots of people in the factory had tried this before but there was not enough room to install them. Anyway, we did put them in and with them, it made it possible to balance the car really well." Herbert Muller is later quoted as saying: "...Officially, of course, the springs were supposed to be 'supplementary' so as to suit the rules and in 1974, we sold them to customers for their RSRs."

From other Excellence articles over the years, here are pics of Tom Linton's 74 IROC (yellow-911 460 0016) engine bay with gussets on the shock mounts (could have been done in later evolution) , but another restoration article shows the engine bay corner for the 74 RSR of Jagermeister (911 460 9060) with weldments to stiffen the corner joint, but no gussets on the shock mount.

Also, the Road & Track article form August 73 which shows the specs for the 73 RSR of John Skoien (1008)...torsion bar suspension...no coil springs mentioned, but maybe the adjustable tube shocks were more than just changing jounce and rebound.

So it seems there were many variations of how the STs/RSRs were stiffened by the factory or customers, but over time almost all got the gussets and other reinforcements in the engine bay.

[advtracing]

Hi guys , earlier you touched on the kremer cars and there use of the t body as a base , the sister car to gibs being the yellow with red , was this such a set up ? was the car run by j.fitzgerald #80 in the 72 le mans a t that was built to ST spec?
Looking for details of this car as another possabilty. As it appears it may not to be a geniune ST factory build does it list on any of the threads to date?

[HughH]

John

I would be surprised if ANY of the Kremer cars were "factory ST builds"
I suspect all (or almost all) would have been cars bought either as production cars or partially completed shells, and then stripped and rebuilt by Kremer using the factory ST kit plus their own parts

That is one of the things that I would like to find out from this thread.

I think that the following cars pictured are all different ones and likely to be all Kremer built - but apart from the green one that is supposed to be 911 250 0335, I have no record of numbers or whether they were an S or T base

I dont think you can rely on race records from the time because they would be more likely showing engine configuration as the descriptor than chassis origin

[Flunder]

My memory tells me that the 2,3L Kremer-prepared cars were built using T chassis manufactured by Karmann.

They were the lightest and cheapest to buy.

I believe that Kremer was permitted to purchase semi-finished cars, unlike everyone else. They had a back door to the Race Dept for parts and had a huge influence on the direction of development of the RSR.

This lovely image shows a Special GT Group 4 Kremer 2,3L car sitting nicely in the pits at the 'ring in 1971.

To my eye, this is the finest image of a 2,3L car. It just looks right.

Photo credit to the wonderful Porsche GT (Grand Tourisme as Raj properly points out below) book by the gents at Petrolpics.

[HughH]

I was looking again at the pictures of the 5 cars I posted above

Almost all of the period competition cars I have seen photos of have the electrical cutoff switch on the LHS - not surprising as that is where both a battery is and the fuse panel.
that is the case with 4 out of the 5 cars pictured above

HOWEVER the yellow #64 car seems to have the cut off switch in the RHS horn grill.

I know that car was a different one to most ST's in that it ran in GT 2.0 at the Nurburgring (European 2-litre Sports Car Championship for Makes Round: 6) (in 1971) AND it is listed in the entry as a 911T.

indeed all the other 911's at that race were listed as T's as well.

how many other cars are out there with a cutoff on that side??

[letsrollbabe]

Hugh:

I had noticed that cut off switch on the passenger side too. I think the factory practice was to put it on the driver side, but maybe Kremer decided to locate the battery on the right side for this ST, and decided it would be easier to do the cut off switch on that side also.

Here is a shot of how the factory mounted the Bosch cut off switch on the driver's side fender wall for early STs. Notice there are 2 cables going to the switch (mounted upside down). One cable ran from the DS horn grill and the other ran from either the instrument panel or on the cowl area just outside the driver side wind screen.

John...there are lots of little details to think about!

[letsrollbabe]

QUOTE: Flunder:

"My memory tells me that the 2,3L Kremer-prepared cars were built using T chassis manufactured by Karmann.

They were the lightest and cheapest to buy.

I believe that Kremer was permitted to purchase semi-finished cars, unlike everyone else. They had a back door to the Race Dept for parts and had a huge influence on the direction of development of the RSR."


Tom:

Edmond Harris confirms this also. He said that the factory also used Karmann 'T' bodies for their STs because of their light weight, but numbered them with 'S' VINs.