Factory S/T questions needed for build

[Zithlord]

Raj/Hugh/others; would you please have a look at the new S/T tread in the technical section?

Thanks

John

[letsrollbabe]

John:

Your goal is a worthy one, but as you can see from these great responses so far, it will not be an easy path to follow...just from the mechanical details let alone the cost side. I chose to try to recreate an existing and fairly well documented car, which makes the external features easier to see and decide how to deal with. Features such as those deleted, seam welding, are more difficult but can be researched from several of the sources aleady responding, plus others around the world. Edmond Harris (www.edmondharris.com) has owned many ST/RS/RSRs and is very knowledgeable about the details of them, and he has many NOS and other 'real' parts from these cars. He was very responsive in replying to my questions about the Kremer ST.

My philosophy in doing one of these 'recreations' (which is a term that more accurately describes an effort to duplicate a car in significant detail.) is to think about the total car at first, and decide the major cost items...engine, transmission, suspension, body details (flares, core body, oil coolers), seats, interior and then make a list of what those items will cost to duplicate as close as possible. Then, after the shock wears off, begin the process of deciding which are more important in representing the final product...in performance, and cosmetically. The cost of a true representation of an original twin plug engine is somewhat staggering, so that is a good place to start with decisions. Priortizing the list of features will help to keep the project realistic for your budget, and doing as much of the work yourself will help a great deal to control the costs.

Since most STs evolved over time, and then were 'restored' by someone who may have had priorities other than trying to duplicate the 'original' features...it is possible that you can create a car that is more accurate than the existing 'restored' original...at least for one period of its life. Keep in mind, however, that the value will never be near the original...because without the correct VIN, and historic record, it is not that unique car from the past.

I will put together a CD of pictures for my project to bring to NZ in March.

Gib

Edit: I forgot to mention the decisions involved with finding 'original' parts, or using reproductions which are much less expensive...and sometimes better functioning than originals. Also, modern suspension features like bushings, sway bars, torsion bars, brakes can all improve performance and for the most part are unseen (however, those anal geeks [smile] will still find those deviations). Finally, those wider Fuchs wheels and tires to fit are big cost items. Fortunately, welded wheels using Fuchs parts can be done, which are at least as strong as the originals. Harvey Weidman uses 2-8x15s to make an 11x15, and 1-6 plus 1-8 to make a 9x15 with no 'bands' or spacer sections to make the width. They end up with one weld, and cannot be told from originals from the outside. Also, Zuffenhaus (http://www.zuffenhaus.us/defaultNew.html) is reproducing Fuchs 15 in. wheels. The Michelin TB 15s are the only wide radial street approved tires available in the correct diameter for 15in., but they are expensive. There are several track tires available with some tread (Hoosier TDs, Avon, etc) and track tires can be grooved or cut to make treads that closely duplicate original treads. Roger Kraus (www.rogerkrausracing.com) does the grooving, and I am sure there are others, maybe in your neck of the world.

[advtracing]

Thanks gib , what i am setting out to do is produce a car that might have left the factory in the 72 era. As discussed as this was the last year of the st going on to the rs and rsr era what would have been the changes in that year? Did they start to introduce items on the car that were later on the rsr's?
A lot of the photos have been pre 72 and as such may not have had the rsr touch.
As for the big picture , i am not going to be using alot of geniune parts.
Due to a big part the fact that nz is along way away from the rest of the world and the exchange rate is killing me !!
We have a great resource down here of talented craftsman and due to our distance away have had to get use to building it ourselves!! i plan to do as much work my self to save on costs and will fab. up what ever i need .
Out of all the items i need the engine is the only high cost area , so i have allocated $20,000 to do this as i will build it myself with input from some local engine builders.
The base car did not cost alot to start with , it was a runner and i drove it home . At a cost of $7000US with geniune leather sports seats , take the seats out of the picture and base car cost $2000 .
I look forward to catching up when you get over ,if you decide to stay in auckland for a day or two we can set up some accom. for you.

[letsrollbabe]

John/Tom:

Here is a pic of the Kremer 72 2.5 ST taken at Moorespeed (by Moorespeed I think) of the engine bay cross member. It does not appear to have any reinforcement around the shock mounts or where the cross member attaches to the boxed sections, as was later used on the 73 RSRs. Maybe the factory did some reinforcement prior to the 73 RSR, but I think most of the significant reinforcement came as a result of the observed stress from using coil over springs solely, and not as just helper springs while retaining the torsion bars.

This car began life as a 911T (911 250 0335) so was not a factory reinforced shell when Kremer built it into an ST for competition. They used the 911T because it was homologated at a low weight, a practice the factory began for STs in 70/71 in Group 3 (I think).

Gib

[advtracing]

Thanks Gib, Matts car showed the same so that solves the question . on to another area ,so i can do some work over the weekend , in the interior rear you would have removed the mounting points for the rear belts and seats and the brackets for the interior panels so to get a smooth inside body for the carpet cover??
I would guess that these would have been a standard removed items for the s/t anyway?

[letsrollbabe]

Raj:

The question is: when were these reinforcements done? This car evolved like many STs did with more 'race features' I think. Did it have coil overs at some point? Do other unmodified Werks STs have these reinforcements?

Gib

[letsrollbabe]

Raj:

The coil mount plate looks like a different weld bead than the strengthening gusset welds. The gusset weld beads are more concave and thinner, while the coil mounts have a rather large converse shape. I would say they were done by different 'craftsmen' indicating a different time. The STs had those coil mount plates originally, so they were likely done first.

Did the RSR version of your car have coil overs, added during that August 72 factory rework?

[Flunder]

Raj:

Thank you for posting so many fascinating pics.

Does the Zasada car also have its jacking points gusseted?

Thanks again,

Tom

[letsrollbabe]

Raj:

As quoted in John Starkey's R, RS, RSR (3rd Edition), Singer says they started using coil springs at the Paul Ricard track tests in late 72. These springs, which were not homologated until May of 73, were one of the reasons why the RSRs had to run in Prototype class at Daytona, and other races like the Targa Florio (factory cars). From everything I can find in various books describing the rear supsensions on the 73 RSRs, both torsion bars and titanium coil springs were used on factory cars, but the springs (steel not titanium I think) were not offered to customers until later in the racing season. I think it was in 74 MY with the 3.0 RSRs and 2.14 turbo that the torsion bars were eliminated to save weight. This required heavier springs, and put greater stress on the cross member.

Here is my picture of John Skoien's 'unmolested original' RSR engine bay (which looks very similar to your posted picture), taken at the R Gruppe meet in Santa Rosa in 06. It appears there was no reinforcing of the shock mounts from these pics, which is not surprising since John's car (360 1008) was built in April 73 for the US market (before spring homoligation).

All this is to point out that (I think) the cross member reinforcment was done because of the increased stress caused by the coil over springs, and it would have been done starting in early 73 most likely on factory cars (probably Kremer, Holbert, and Brumos would have done it too). I think any reinforcement of ST shock mounts would have been done in the spring of 73 at the earliest (there are probably exceptions somewhere). Maybe there is documentation to dispute this, and it would be interesting to find it. But the fact that the Kremer ST, which had much factory support, did not have the reinforcement would be a strong indicator that it was not being done in the 72 racing season. Is there any documention of coil springs being retrofitted on an ST?

All this should be added to the 'Ultimate ST' thread.

[Flunder]

Gib:

Refer to the interview by John Starkey with Erwin Kremer back on p.121 or so in John's book Porsche 911 R to RSR.

Kremer states that he was the first person to put coil springs on a 911 and that he made them up himself at his garage in Cologne.

The way the interview is written up, Kremer makes that statement immediately after some commentary relating to his development of the wider wheel arches and wider wheels with the 2,5 cars.

I wonder is John Starkey can fill in the timeline accurately.