The 917/10K was developed from the highly successful endurance racing version of the Porsche 917. In the 1960s Porsche were determined to win the 24hrs of Le Mans and to do so they developed the 917 to compete in the up to 5000cc category of sportscar racing. The original 917 with a long-tail body and moveable aerodynamic aids first appeared at Le Mans in 1969, but proved to be both unstable and unreliable and failed to win the famous race on it's first time out. In 1970, a new short-tail body was introduced called the 917K (the K standing for Kurtz, or short in German) which was slower down the long Mulsanne straight at Le Mans than the similar long-tail 917s (which were much improved over their 1969 predecessors, and were known as 917Ls) but far more stable in the corners and much less tiring to drive as a result.
In 1970, Porsche scored it's first Le Mans win with a 4.5 litre Porsche 917K, and in 1971 another 917K with a newer 5 litre engine repeated the feat to scored Porsches second overall win in the French race. 917s were not in fact prototypes, as the 3 litre engine size had been in force for non-production sportscars since 1968. But thanks to a loophole which stated that only 25 cars had to be produced to be eligible to race as production sportscars (which were allowed to use engines of up to 5 litres in size) Porsche were able to develop the superb 917. Porsche managed to produce the 25 required cars at enormous effort (both physical and financial for what was then a much smaller company than it is today) to qualify the 917 as a production car.
Unfortunately for Porsche, the FIA (motorsports governing body) decided that the 5 litre sportscars were getting too fast for their own good and in 1972 the category was dropped favouring the 3 litre prototype class. Porsche had seen that the writing was on the wall for the 917 in Sportscar racing and decided to develop a version of the car for Can-Am and other forms of Group 7 racing (such as the European Interserie). Porsche had scored a lucky win in Can-Am racing in 1970 with an open version of the 908, but in general the car was an also ran against the then dominant team in Can-Am racing, McLaren. The problem was not the chassis (which handled well and was not too far off the McLarens in terms of overall weight) but the engine, which was not powerful enough to compete against the huge and hugely powerful Chevrolet aluminium big block V8s used by McLaren and most of the other front running Can-Am teams. A spider version of the 917 called the 917PA was also used in Can-Am with the same chassis and flat 12 engine as the 917 coupes racing in the world sportscar championship. Like the 908, the 917PA was just not powerful enough and far too heavy compared to the front running Can-Am cars in 1969 and 1970 to be a front running car.
In 1971, Porsche decided to develop a version of the 917 specifically for Can-Am. A shortened 917 chassis was used with new open two seater bodywork (to comply with one of Group 7s few rules, which required all competing cars to be both open and nominally two seaters, with all wheels covered by the bodywork). The new version of the 917 was known as the 917/10. 1971 was the last year McLaren managed to dominate the Can-Am series (in which they had been practically unbeatable since 1967) but the new Porsche 917/10 showed great promise. It was still too heavy and not powerful enough to compete fully with the McLarens, but given Porsche's record in other areas of racing it was felt that they were building up to mount a very serious challenge to McLarens dominance in Can-Am.
Group 7 racing was as close to an unlimited racing formula as there has ever been in the history of organised motorsport. By 1971 there were more rules than their had been in the late 1960s, such as new rules banning movable aerodynamic surfaces and wings and bans on active ground effect vehicles such as the Chaparral 2J which used powered fans to suck air out from under the car causing negative pressure and literally sticking the car to the road through most corners. Most of the newer rules were motivated by safety concerns, especially in the case of moveable aerodynamic aids, which if they broke (and they often did!) caused sudden and severe loss of stability which frequently resulted in a big accident. What remained "unlimited" in Group 7 racing for 1971 was the rules concerning the engine and additionally there was no minimum weight requirement meaning designers were free to use whatever exotic materials they wanted to try and reduce the overall weight of the cars. The 917/10 had a complex aluminium spaceframe chassis with a lightweight glassfibre body which was considerably heavier than the nominally more advanced and lighter aluminium box section chassis used by McLaren. Hence the main area for improvement that Porsche decided to concentrate it's efforts on was the engine.
Apart from a prohibition on gas turbine engines, there was no limits on engine displacement, number of cylinders and so on, and no ban on turbo or supercharging. The 5 litre flat 12 engine from the 917 coupe was enlarged to 5.4 litres for the 1971 917/10 which made it a superbly powerful racing engine, but compared to the huge 8 litre+ aluminium block Chevrolet V8s it still was not powerful enough to make the 917/10 truly competitive. Two projects to address this problem were undertaken by Porsche. The first was a huge 7.2 litre flat 16 engine based on the existing flat 12 which produced approximately 880bhp and which had it been used in the 1972 917/10 would probably have enabled the car to compete on level terms with the McLaren-Chevrolets. However, Porsche chose instead to go with the other option for increasing horsepower, that of turbocharging.
Turbocharged engines had been around for some time in 1972, but few had yet made a satisfactory turbocharged engine for road racing. (Although BMW had seen success in European Touring car racing with their Turbocharged 2002s since 1969). The problem with engines of this type revolved mainly around throttle response times and consequent "turbo lag". At low engine revs the exhaust gases produced were insufficient to drive the turbochargers to produce any meaningful power boost. So when the driver first opened the throttle there would be a discernible lag until the exhaust gases built up (as the revs rose) before the peak power would come in. Hence the car would be sluggish going into a corner but would suddenly deliver a huge slug of power mid-corner which could be difficult to control. Additionally, when the driver took his foot off the accelerator, there would be another lag where the turbos took time to spool down hence the engine would still be producing power after the throttle had been closed. Not good when heading into a tight corner at the end of a long straight.
Porsche in the late 60s and early 1970s did not usually race it's cars as a works team but instead employed other racing teams to race Porsches as privateers with factory support. The 1971 917/10 was driven by Swiss driver Jo Siffert who was linked to the John Wyer organisation (whose Gulf liveried 917Ks were extremely successful in sportscar racing at the time). Sadly he was killed in a BRM F1 car in October 1971. Subsequently Porsche decided to go with another organisation to help develop and race it's new turbocharged Can-Am car, the highly successful American Penske racing team. Roger Penske and his star driver (and engineer) Mark Donohue had competed in the Can-Am series between 1966 and 1969 (using first a Lola and later a McLaren chassis) but had pulled out of the Group 7 series after only one race in 1969 as they were unable to field a car which was competitive against the mighty McLarens (who managed to win all the races in the 1969 Can-Am season). A hallmark of the Penske team was meticulous car preparation. Not only were Penskes cars usually quick and highly competitive, but he also insisted they were the best turned out cars as well. Flawless paint jobs and bright chromework were the order of the day. Penske felt this reflected the level of professionalism needed to be a top flight racing team.
In the Autumn of 1971, Porsche added a pair of turbochargers (of the type normally used on turbodiesel truck engines) to a 5 litre flat 12 engine (one turbo per bank of cylinders) and in testing saw huge power outputs, up to 1500bhp at times. Jo Siffert (prior to his death) and Porsche test driver and racer Willi Kauhsen did much of the early testing of the new turbo engine and found it extremely difficult to drive. The problem was the severe turbo lag, which gave the engine an all or nothing throttle response, described as being like a "light switch", with a time delay.
When Penske and Donohue became involved with the turbocharged 917/10 project (the new version being known as the 917/10K, K standing for "Kompressor") they immediately realised the two main problems to be solved to make the car a Can-Am winner were engine response and downforce. Mark Donohue was initially not well understood at Porsche who were not used to a driver with a background in engineering and with such experience in setting up and developing racing cars. However, he managed to win the respect of Porsches 917 Can-Am project manager Helmut Flegl, and the two of them developed a close working relationship and personal friendship which brought the results needed to develop the new car into a winner. Porsche were initially against adding a large rear wing on the car as they were obsessed with straight line speed which was cut by having a large drag inducing rear airfoil on the back of the 917/10K. However, Donohue managed to persuade them that the wing gave them an extra 5mph+ in cornering speed and that despite the drag the car could carry most of that cornering speed advantage for most of any following straight on the existing Can-Am circuits.
The first turbocharged engines refused to run smoothly and indeed were almost impossible to start. Donohue suggested to try tuning them without the turbos first. The engineers at Porsche initially thought this to be a crazy idea, but it turned out he was right. The engines were set up to run well at high turbo boost pressure, but off boost (at low revs) they ran terribly. But by tuning the engine to work well in normally aspirated mode first, and then adding the turbochargers, Porsche managed to make the new engine run well throughout the rev range. Bosch were very instrumental in sorting out the turbocharged engine with an advanced fuel injection system that they developed for the engine with the help of the information gathered by running the engine with and without the turbos to learn its characteristics.
Now the Penske/Porsche/Donohue combination were ready for the 1972 Can-Am championship. Arriving at the first race at Mosport in Ontario, Mark put the car on pole position against McLaren driver and 1971 Can-Am champion Peter Revson in 2nd position on the grid. At the start, Revson made a better start than Donohue, who admitted the Porsche was still suffering from some turbo lag, but Revson did not get to the first corner first. The Porsche had come on boost by then and Mark powered ahead of him before the first turn and into the lead. However, a sticking throttle requiring a pit stop to fix dropped the Porsche down to 9th place, leaving the two factory McLaren M20s into the lead. Donohue fought back however and ended up in second place behind Denny Hulme, in one of the McLaren M20s.
The next race was at Road Atlanta in Georgia. A week or so before the race, Mark Donohue was testing the car on the Road Atlanta circuit when a fastener holding the rear bodywork failed while the car was travelling at speed. The rear bodywork including the wing flew off the car and the resultant massive loss of downforce caused Mark to loose control of the car and crash heavily. The whole front section of the car was ripped off and Mark was left strapped into what remained of the cockpit with his legs hanging out onto the tarmac. 1967 and 1969 Can-Am champion Bruce McLaren had been killed in just such an accident at Goodwood in England in 1970. Initially he seemed to have had a lucky escape, but his left knee was badly injured. A local orthopaedic surgeon who specialised in knee injuries (and covered the local Atlanta Falcons football team) examined Marks knee and recommended surgery. Thus for the first half of the 1972 Can-Am season, Mark Donohue was forced to sit on the sidelines.
Penske had intended to run their Can-Am effort as a one car show, with Mark as its only driver. So to replace their injured star driver, Penske drafted in George Follmer to drive the new Porsche. Follmer had to get used to the unusual driving style demanded of him by the turbo engine in the Porsche, but he managed to win his first race in the car at Road Atlanta. Watkins Glen in upstate New York hosted the third race in the series and Follmer just could not get to grips with the McLarens, and ended up finishing a disappointing 5th. Things came good again however in the 4th race at Mid-Ohio and Follmer added a second win for the new Penske Porsche, helped by new turbos 20% smaller than before which reduced turbo lag. He won again at Elkhart Lake and would have made it three in a row at Donnybrooke in Minnesota if he hadn't run out of fuel on the final lap while leading. Donnybrooke also saw the return of Mark Donohue to the team, but he failed to finish following a puncture. French F1 driver Francois Cevert won in a privateer McLaren M8F.
The next race at Edmonton in Alberta saw Donohues first win in the 917/10K. Team-mate Follmer was 3rd after trouble earlier in the race with a flat tire. The final two races of the 9 race 1972 Can-Am season were held at Laguna Seca and Riverside, both in California, and both were won by Californian native, and now 1972 Can-Am champion, George Follmer.
Everyone associated with the Porsche turbo project was delighted at winning the Can-Am series against the previously unbeatable McLaren team, although Mark Donohue was bitterly disappointed that it was George who won and not him especially as Follmer did it using Marks car (in his autobiography "The Unfair Advantage" Mark described seeing Follmer out in the 917/10K was like seeing another man sleeping with his wife. He did not wish ill of Follmer but he very much regretted he could not have competed in all the '72 races as he had planned to do. His time would come the following year in 1973, when with the much improved Porsche 917/30 he would dominate the season and win the '73 Can-Am championship.
This model of the 917/10K was made by Minichamps as a Porsche dealer edition. As such it came in a different box to the regular hobby shop edition 917/10 releases by Minichamps and had the Porsche part number WAP.021.600.15 (which was needed to order the model from the parts department of any Porsche dealership). One benefit of this model being a dealer edition was that it came with the correct "L&M" sponsorship logos. As L&M are a cigarette brand, most Minichamps releases would not be permitted to be sold with the L&M logos on them. The reason for this is most model cars, even the collectable ones are legally considered toys and as such are not allowed have any cigarette advertising on them even if it is historically accurate to have the offending logos on the model. This is a source of annoyance to most collectors I know of as it can ruin the look of an otherwise superb model and personally speaking I don't think anyone would be encouraged to start smoking by looking at a model car with cigarette logos on it. After all photos of the real thing are freely available with the tobacco markings in place. Thankfully though, dealer models seem to be considered differently by anti-tobacco laws (perhaps they are not considered toys but car parts?) hence this model has the correct logos.
As I'm currently in the middle of a house move (as of August 2006) all my models including this one are in storage so I'm not able to review it properly at present. Once I have my models out of storage I will review this model in detail and add an appropriate ratings scale to this write up.
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