Differences ST and RS/RSR

[gwag]

I've had a hard time 'searching' this as fragments like ST/RS/RSR don't get included, so I apologize as I'm sure parts of this I'm sure have been covered.

I understand some of the historical differences, but I have a hard time understanding some of the other differences including cosmetic differences. It seems like there was historically a bit of variability even with MYs so it may make tracking differences difficult.

I know that the ST was a 'sport purpose' factory car (rare), and that 'kits' were available to make after-market ST cars. Also seems like there may be overlap in when these cars were made and therefore similarities between ST/RS/RSR.

Would really like to have a 'definitive' reference in the differences AND similarities, both from a mechanical (drivetrain, etc) AND cosmetic (flairs, etc) standpoint.

[Bill Verburg]

2 of the better affordable books on that have some coverage of these cars are
Starkey's '911 R-RS-RSR' and 'From R to GT3R' There are probably others that I haven't acquired

ST was introduced in 1970 as the successor to the earlier swb 911R, They were developed by Rico Steinemann, Porsches racing manager at the time. They took a basic 2.2l 911S and homologated it into Group 4(special GT) and Group 3 (production GT) classes
these cars were lightened extensively
Al. hoods & bumpers f/r, wire mesh grill, stripped interior, rally seats glovebox lid, sunvisor, heater duct delete, larger plastic gas tank w/ filler thru hood, roofs & part of the floorpan used thinner steel, some had Al. doors 840kg wet weight. to 789kg for the 1970 Tour de France. 2247cc 245hp Bosch MFI motors w/ stock 46/40 valves and Carrera 6 cams, 10.3 cr. External optics are the 2" wider fenders front and rear with wider wheels & tires. In front the flare could accommodate a 9" wheel(same as later RSR & 930 front but w/ different shape. IN back the ST flare could accommodate a 10" wheel, this is wider than the later RS but narrower than the later RSR.


36 were built to ths spec. but there were options that allowed a variance
options - plastic bumpers, plastic hood, plexiglass side and rear windows, thinner
glass windshield, various rollbars

for '71 the bore was opeded to 87.5mm for 2381cc, 250hp@7800 188.4 lb-ft@6200, S front brake calipers

The RS was developed in '72 based on the new 2.4L motors and 915 transmission and sold as a '73 model, optically it has the same front fenders as a regular 911 but ~ 1" wider rear fenders. This allowed 7 & 9" wheels and was the basis for the RSR homogenization w/ 9 & 11" flares & wheels(again +2" rule). RS has 2687cc 210hp@6300, the RSR had a 2806cc motor 308hp@8000

[RichardNew]

[charwood77]

cosmetic differences are primarily with the fender flares

RS will be very similar to a SC or Carrera flare (front and rear) although very slight contour differences.

RSR will have wider front and rear flares (similar to a 930, but long hood)

ST will have same front flare width as the RSR but a rear flare somewhere in between RS and RSR.

more info here:
st rear flares

[gwag]

Thank you everyone.

Exactly what I needed to get started.

Will order the book.

Someone needs to write a small book on the 'ST'.