Gib, The 77 car was the last 2.5 built by Porsche. The cooler change must have been a add on after to come up to 73 specs? What do you think?
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Gib, The 77 car was the last 2.5 built by Porsche. The cooler change must have been a add on after to come up to 73 specs? What do you think?
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Harvey:
I had thought that these front mounted coolers were added by the privateers, but I think the pics of the Strahle car were taken in 72, and this shot of the Kremer ST with the Strahle car behind is definitely in 72, so I think Paul Frere's comments were applicable to the 72 STs. It could have been a change made during the season which was adopted by few racers because it meant changing a lot of plumbing. The early factory cars do not show these coolers, which would support a later modification...but in 72 not 73. We know the red 72 ST/RSR prototype that ran in July at the Austria Ring had the front cooler as the RSRs all were to have, but the photo evidence of STs running in 72 is hard to deny...plus Paul Frere would not have included that comment without factory confirmation. This comment was under the 2.5L ST section, and before discussion of the 2.7L 73 RS.
Gib
In "R-RS-RSR" Starkey mentions "thirty" lightweight bodies being built by the factory around 1970 (pg. 15, 3rd edition). In "Excellence Was Expected" Ludvigsen mentions 30 sets of thin roofs, cowls and floor pans, and 100 sets of lightweight fenders, bumpers, hoods, etc. for the same time period (pg. 626, 3rd edition). Twenty factory ST cars being manufactured is a number I have seen before, but I do not remember what time period was being referenced, where I saw this number, or the source.Quote:
Originally Posted by varunan123
"Excellence did an article on this car in August 1999, and it was this article that really started my keen interest in STs. "
small world , Gib i had this article also pop up out of my mag collection when i started the ST drive , which led me to 911sreg and to your build ...:D
The #58 Brumos 'ST', 911 030 0043 production #1000291 started life as a Bahia Red 1970S with M470 comfort package, black vinyl interior, Blaupunkt radio, tinted windows according to factory records and was shipped to Brumos in Dec. 1969. The body when discovered in Mexico had fiber glass front fenders, hood, and the rear flares were 'hand fabricated by someone in Jacksonville' according to Jennette, and were overlap welded on.
This car was most likely done as an ST by Brumos, and points up the problems that have been discussed in identifying these cars as STs that were sold to customers and then converted to ST specifications with the 'Competition Car kits'. This car would most likely not have been one of those '20-30' light weight factory cars built in '69-'70.
Raj, we will probably not find any T or E models that were built by the factory as an ST, but with approx. 80-100 or so of these ST cars that competed in world wide venues between 1970 and 1972, many more were built from 'kits', or maybe just put together by the factory without special identification. And if these cars have a race book, or documented race history, with features indicating they had ST kit specifications at some point in their history, they have a right to claim ST status IMO, and have a right to be part of the history of these transition 911s in race competition. After all, it was the factory designed features that could be bolted onto existing 911s that made them competitive.
Gib
"We don't need no stinking lists...."
Raj:
The 'Information Regarding Porsche Vehicles Used for Sports Purposes' first issued in 1968 is the beginning of THE LIST of parts for 911s to be used in Rally or track competition. That list evolved over the next 5 years to special kits that had to be ordered complete, etc, but all of the ST parts were on the list which could be ordered by any privateer for ANY 911 to make it into a 'Competition Car'. Christophorus Magazine ran an article on these kits that showed both 911 and 914 kits for sports purpose, which actually showed the front mounted oil cooler for the 72 ST.
Flunder's thread 'Another Hotrod' has posted the documents that show part numbers for all the ST parts which were available to customers. It was not rocket science for experienced guys competing on the track by 72, they knew what they needed to compete...twin plug 10.3 CR engine, oil cooling, tranny gears, fender flares, wheels/tires, stripped body/interior, FG hood, alum rear lid, etc. These items were homologated by the factory, so no problem getting them through tech.
I've got a set of those pistons, those cylinders and, possibly, those heads. Is there specific text to describe the parts in the photo?
Marco
there is in the parts list that Gib posted.
I don't think the part numbers are in the article - I cant find my copy of it at present
However from the 72 parts list (published in 71) the part numbers for the cylinder section are as follows:
Gib, the front cooler shown in that Christophorus Magazine article (August 1970) is for the 914, not the 911.
The front coolers used on the 911 ST were shown on the cover of the February 1973 issue, which featured a photograph from the 1972 European Championship.
Of particular interest to me is the fact that modifying the S front spoiler with a cooler would have reduced the front end lift on these STs. I've driven my car in this configuration (front RS spoiler w/ cooler, ST flares, no rear spoiler), and it can be unsettling to drive during hard downhill braking and when traveling through sweepers at high speed. It's possible that reports of similar experiences during the 1972 season may have influenced the factory in developing the rear ducktail to balance aerodynamics.
Randy:
Thanks for pointing out my error in which car had the front cooler in that 1970 Christophorus issue. I have a well-used February 73 Christophorus, and looking closely at it, (which I hadn't really done before) there are 3 STs with visible front coolers. The Strahle ST on the right, and the 2 cars on the left, with the cooler on the red/white ST barely peaking out from behind the orange #8, whose cooler is obvious. This really great photo was taken by Thomas Zimmerman, though not sure which 72 event. It is one of my favorite race photos of all time.
Paul Frere gives factory wind tunnel test results in his Porsche 911 Story, and you are right, the 72 front air dam greatly reduced front lift at 143 mph from the old style: 183 lb to 102.5 lb. But it also had the negative effect of increasing the rear lift. In further wind tunnel tests at 152 mph with the RS front air dam, the rear lift without a ducktail was increased to 320 lb, but reduced to 93 lb with the ducktail. It is no wonder that a rear spoiler became necessary for successful competition with the 911. Those tests also showed that the overall drag coefficient was reduced with both front/rear spoilers as compared to a 911 without either.
I have not seen data comparing front lift with a front oil cooler and the RS air dam with blank plate, but you are probably right...the cooler drawing air through it will reduce front lift....but without that rear tail, it will probably make the rear lift greater...and that is what you have experienced.