Not according to Starky, 'From R to GT3R' pg 56, "Group 5"

53 3.0 RS were built as 'homolgation specials' ie the basis for the '74 3.0 RSR, similar to the '73 2.7RS program which was the basis for the 2.8RSR in '73

IF you have reliable sources that contradict this please do post what the source is.

Frere's books, Ludvigsen's books, etc.

JR

Great info, thanks guys. I've also not been able to determine if the flares on the IROC RSR were steel or fiberglass. My understanding was 73 RSR was steel, 74 RSR was steel, so the 74 IROC RSR in between the two should have been steel.

I think if I follow this thread:
-The 73RSR was steel
-The 73 RSR became the body for the 74 RS
-The 74 RS was likely steel then as well
-The 74 RS body essentially became the 75 turbo street car (steel).
Does that sound right?

And then the question is when did they start using fibreglass?
-74RSR (vented?)
-934 (group4?)
-935 (group 5?)

Looking forward to seeing someone confirm and finally sort this out :)

'73 RSR fenders were steel, w/ f/g doors and bumpers and Burzel

'74 IROC fenders were steel, w/ f/g doors and bumpers and wings

'74 3.0RS fenders were steel

'74 RSR 3.0 fenders were f/g along w/ the f/r lids and seat bases

Norbert Singer, " Where our own factory team was concerned, I remember that we started the 1973 season with a normal G.T car and, I think, after one or two races, at Monza, we got a protest about the bearings on the rear suspension. So, during the meeting, I changed the cars category to Prototype(Group 5)... we raced there as a prototype."

Frére, 'Porsche 911 Story' 6th ed, pg 247, about the '73 2.8RSR. "Designing a new racing car to conform with the new Group (sports-prototypes) rules was out of the question for reasons of time and money, and also because the future of sports car racing looked very uncertain. So the best choice seemed to be to further develop the 911 to run in the European GT Championship[ which was to be first organized in1973... to achive the set targets a new model had to be introduced in the 911 program and at leat 500 examples built to obtain its homologation as a Group 4 Special GT car" these were the first 500 911 2.7RS

" even before it was homologated in Group 4 the Carrera RSR 2.8 won the Daytona 24 hour" later in the year the classification was changed to Prototype" see my above post w/ Norbert Singers comments, Group 5/Prototype

Frére further adds that the 3.0 liter was originally used in the factory sports prototype Carrears but was later used in some GT models before the end of the season.

again, Frére, the Carrera3.0 RS obtained it's homologation in Group 3 as a normal progression production car of which 1000 a year must be made for homologation, as an evolution of the RS 2.7 after 100 units were completed.

Ludvigson, "Excellence Was Expected' vol 2 pg 643

the 2 factory 1973 Daytona911(2.8RSR) raced in Feb '73 were based on the Group 4 2.7RS, however though the 500 cars had been built and inspected the homologation could not be grated until March 1 1973, so the cars were run as prototypes on a technicality, ie Group 5

They ran as prototypes in that one race. I think you'll find that the new rules that came into effect in 1972 were quite different from the old rules. Less emphasis on prototypes and more emphasis on GT cars. The new Group 5, for GT cars, wasn't fully defined until the 1976 season, even though it was announced years before. So the two 1973 Daytona cars raced against the prototype cars, not the GT cars. Group 5 was contested by the 935, years later.

After Daytona 1973, the RSR's ran in group 4.

JR

This is good stuff guys!

How does this compare to which class the 917 ran in?
I've always wondered how the transition from 917 to RSR or 934/5 happened?

I know it isn't news to some of you but will be to me.
Thanks

(and Mr. Snodgrass, thanks for reviving this thread!)

yes, the cars were intended for Group 4 GT and yes they had satisfied the requirements but they raced in Group 5 Prototype because of the time needed for the paper work to became official and then stayed there because of the suspension protest.

Then the 3.0RS was homologated in group 3 as an evolution to the 2.7RS, which had been accepted as a FIA Group3 GT and yes the '74 3.0RSR was then accepted in Group 4 GT

None of that is disputed

What is disputed is you assertion that the '73 2.8RSR ran in Group 4 GT, it was intended to and it was legal it just never did officially, because of a delay in paper work and then a protest which Norbert Singer chose not to fight.

The year is 1969 the month March the day 12, Press Day, Porsche introduces the world to the 917 at Geneva.

It was originally intended to run Group 4 Sports Car but the necessary 25 examples had not been built, On March 20 Porsche had showed all the parts to the inspectors but not all of the cars had not been assembled, Group 4 homologation was denied.

On April 21 the FIA inspectors were invited back, due to a crash program all 25 917s were lined up on display. On May1 1969 the 917 was granted it's official Group 4 Sports Car papers.

In all it took 10 months of intense effort to design and build the first 25 examples.

For '75 934/5 was in Group 4 GT, based on the then production series 930 cars production #s, the 935 was Group 5 Special Production category, which was open to Group 1 through 4 cars that coul be further modified, w/i limits also introduced that year was the group 6 2 seat racing cars, 936.

Just for the record, the fender flares used on the IROC are essentially the same as the fenders used on a '73RSR. Bill Verburg's pic of the white #23 car and Jeremy's vintage pics represent proper '73RSR or IROC fenders.

The IROC were essentially a standardized design and copied ~20x. The rest of the spec. was basically '73RSR on a shorthood.

The shorthood RSR kit had some significant additions, like the slide valve induction, centerlock magnesium wheels, the bigger fenders, bigger bumpers to match, fender vents, bigger rear spoiler, etc.

Porsche's customers ran the RSR in Group 4. Lots and lots of them. Singer chose to run the few factory cars in the prototype class for two reasons. One, he didn't want to comppete against his customers. Two, it allowed him a great deal of freedom to change things and experiment. Lots of those changes got homologated along the way.

JR

Again your assertion that Porsche ran the '73 RSR in Group 4 is the issue

change the subject all you want, the factory ran them in Group 5 for '73

Okay, I understand now. I was speaking of the whole program and I didn't intend to mean just the two factory cars. Sorry for the misunderstanding.

JR

Hello. I just bought a sweet little 68S targa and the seller tells me he raced it in Riverside in 73' and had the all metal flares installed by the guys that did IROC flares. Does anybody know the name if that shop ?

I believe I may have stumbled across a original 74 3.0 decklid. How would I confirm the piece is authentic?

You might start with the part number.

It is buried under some paint and can't read it clearly. Would it be wise to scrape the paint off or possibly use a light bit of paint stripper to expose the part number?