The Porsche 917/10 represents massive overwhelming force. That’s quite something when you’re talking about a car that was aimed at Can-Am, the ’70s race series that in its classic incarnation was based around a virtually no-limits, all-out power formula. This /10 and its younger, even more powerful sister the 917/30 represent the most ferocious, raw racing cars ever constructed.
Up until 1972, Can-Am had been McLaren’s hunting ground, but the arrival of the Porsche factory steamroller quickly reduced them to backmarkers – and also drove a nail into the coffin of the series. By 1973, Porsche 917s ended up carrying almost twice the horsepower of the previous generation cars, using a qualifying grenade of an engine that put out over 1,300hp.
The reason for this factory war machine being made was, as ever, a change of rules.
In 1972 Porsche had found themselves regulated out of their natural habitat of Le Mans and the World Sportscar Championship. The dominant 917 had won Le Mans twice in a row (’70 and ’71), laying the foundation for the marque’s future success at La Sarthe, but the incoming three-litre rules introduced to get some parity between F1 and sports cars didn’t appeal to the company. They decided to turn their attention to their biggest market, the USA. And that required a serious change in philosophy.
They would need power.
A whole lot more power.
Porsche needed to go back to the drawing board, but they hadn’t stood still with the 917 since it was first introduced in ’69.
The coupé had constantly evolved across its short life in World Sportscars, with short and long-tail versions, enclosed low-drag bodies and experimental aerodynamic variants all coming out of Zuffenhausen.
The 917 programme had also fast-tracked the Porsche technical team in developing new racing technologies. Magnesium, titanium and other exotic materials had been used for the Le Mans racer, the entire lightweight tubeframe was pressurised, the flat-12 used twin spark plugs and produced impressive power figures.
All these threads would come together for the firm’s major foray across the water: the 917/10.
Porsches had already competed in Can-Am, with low-key 908 entries and a 917K (a rough-cut spider version of the Le Mans coupé), but they had been underpowered and out-gunned in the face of the big V8s of the established opposition. For the new Can-Am programme, Porsche’s first concern was delivering more horsepower to the driver.
McLaren were clearly in the ascendancy in North America, with their Chevy V8-powered M8s producing obscene power – around 750hp even from their normally aspirated engines. A singleton NA 917/10 competed in 1971 did better than expected, even scoring second places at Mid Ohio and Road America, but it was clear where the problem lay.
The magnesium-alloy, 4.5 litre 180-degree V12 was retained (after a long-wheelbase car with a normally aspirated 7.2 litre 16-cylinder engine was tested and shelved) and raced during 1971 in a car that still bore a big resemblance to the 908. But serious firepower was added the following year in the form of a 5 litre flat 12 boxer assaulted by two big truck turbos. Turbos were still in their infancy during this period, so this was no mean feat, especially when delivered through a four-speed box.
But the result was close to a thousand horsepower and over 900Nm of torque, quickly rising as the car was developed and well exceeding the magical one horsepower per kilo formula…
… in a car weighing just 767kg.
That meant that driving a 917/10 was a delicate affair: power was delivered like a light switch, requiring subtle application of the throttle to prevent the huge rears spinning up and leaving you helplessly bogged down or facing in the wrong direction.
The boost was usually run at 1.3 during a race, with the maximum only used in bursts for qualifying. It was still more than enough.
The 917/10K got to 60mph in 2.1 seconds, 100 mph in 3.9 seconds and 200 mph in 13.4 seconds.
At its heart, an aluminium spaceframe bore all the components of this deceptively small car: the huge, overhanging rear wing and bluff nose make it look much larger than it actually is…
… but see it with a driver in the cockpit and you get a better sense of its true proportions.
The design approach also followed new conventions. Although hand-crafted curves had dominated, now sharp edges and slab sides came to the fore.
Though from face on you can see how the form of body is actually more slippery than you’d expect – it’s less wedge-shaped than the McLaren’s and looks more organic than when you see the car at from the side angle.
The huge rear wing dominates the back of the car, supported by aluminium strakes and secured to the raked rear upright fins.
But whatever the efficiency or not of its aero, it looked like the pure power of the Porsche would batter nature into submission.
The panels were GRP, consisting of two main sections – the big rear deck hinging up for access to the engine bay.
The bodywork directly in front of the front wheels was concave to help produce downforce, with louvres helping air flow.
The legendary Penske squad oversaw the main factory effort in 1972, now with the addition of those huge turbos. The L&M sponsorship was taken from Carl Haas’ Lola programme, transferring the beautifully clean livery (as so many cars of the time had) to the Porsche.
A McLaren M20 took the first win of the season at Mosport in June ’72, but the writing was on the wall: three 917/10s finished in the top five, with Mark Donohue second.
A testing accident ruled Donohue out of the next four rounds, so Penske brought in George Follmer, initially as a temporary substitute.
The following month at Road Atlanta, Follmer posted his first victory in the Porsche, then won the fourth (Mid Ohio), fifth (Road America), eighth (Laguna Seca) and ninth (Riverside) races, with the team running two cars when Donohue returned to action.
Follmer easily took the title, ending five years of McLaren domination.
As if the /10 wasn’t enough, and with the opposition already reeling, Porsche decided to take it up another level and produced the 917/30 for 1973, where a thousand horsepower was its lowest power setting. It was once aptly described as a total weapons system… but that’s another story.
917/10Ks continued to race on alongside the /30 through ’73, meaning that by the end of the season, races became Porsche benefits. There was a final outing for Porsche during the curtailed ’74 season, the last year of the classic Can-Am era before the series folded, killed off by a combination of the global oil crisis, spiralling costs and the hammer-blow dealt to the opposition by Porsche.
This is Follmer’s championship winning car, signed by the man himself.
The 917/10 brought power and glory to Porsche, and was proof that they could turn their hand to pretty much anything they fancied and still expect to win. The ’70s would provide further rich pickings for the team, especially when they returned to Le Mans with the turbocharged 936 (lessons well learned from the Can-Am project), but the 917/10 still stands as a pinnacle of ’70s racing cars, proving that nothing succeeds like excess…
Words by Jonathan Moore
Photos by Larry Chen
Additional photos courtesy of Porsche
I saw George Follmer and Mark Donahue race the 917/10's at Laguna Seca in "72 and I will NEVER forget it. There were a half dozen or so cars out on the track to warm up and one by one, all the other cars started to leave the track to let these to guy's have the track to themselves. Mark and George sounded like a 747 coming up the track. It gave you goose bumps and the air was as still as can be as everyone held their breath as they both broke track records and exceeded 200 mph. I was just floored, I was in AWE!!! Never have I seen or heard anything like it. It's a moment I'll never ever forget. And it's 42 years later. 0 to 60 in 2.1 seconds 0 to 100 in 3.0 0 to 200 in 13 seconds. Someone should bitch slap those wankers at Top Gear (UK)
Wow, miss a day or two miss a lot.
This was one of the cars that made Mosport more famous back in the 70's, some of these
Cam AM monsters are here for the vintage race's we have every year in June.
Great story guys. (Mosport is about 100 km from where I live).
This car is amazing. I have to admit I really wasn't very familiar with Can-Am racing in general but now I feel like I've been missing out! Amazing photos Larry and a great write-up Jonathan. Out of interest, what was Audi's involvement with the car?
900nm & 767kg! Mother of god! And 0-200mph in 13sec? Oh man! No wonder these things were regulated out of competition everywhere! Great story and photos!
wow! what a great post!! awesome combination of two great speedhunters!!
looking forward to next year where they make a return to Le Man!
Impresionante sin palabras , que lástima que hoy en día no podamos seguir viendo estos magníficos automóviles.Las fotos son espectaculares que envidia daría lo que fuese por poder hacer algunas yo también.
Absolutely bonkers! The overhead shot w/o the body panels does it for me--the old shot. The engineering back then was just crazy.
Brilliant article. Just am side note though, the 917K was the coupe from 1970 developed by JWA with the K standing for Kurzheck (short tail) The first open top CanAm 917 was the PA, as it was a joint venture between Porsche and Audi and was driven by Jo Siffert I think
If I'm not mistaken a guy I used to know owned this exact car before he sold it to whoever owns it now. Very cool and was fortunate enough to see it up close and in person several times. Great to see a feature on it. All the racing cars from the 70s and 80s just seemed crazier than they are now.
It's not the power or the weight that gets me as much as the insanely short wheelbase combined with a diff that was 100% locked. 4 digit horsepower, super light weight, with a tendency towards understeer in a time when track safety was an after thought compared to today. Completely insane. Great photos that really highlighted a lot of interesting parts of the car I even missed when I saw it in person!
Wow this was amazing. l can't imagine how in 72' these cars were racing, l mean nowadays they look so menacing and strong that one couldn't believe they're from 40 years ago! l love those big wings and the enormous rear tires, definitely one of the most beautiful racing cars of all time!
Having the driver's feet positioned ahead of the front axle was a common design element, but was the same reason the Porsche 956 was not allowed to race in the USA under IMSA rules a decade later. The balance is phenomenal, but the risk to driver are too great. Same design has helped the Swift DB-1 Formula Ford chassis (early '80s) stay a favorite and choice of National champions even today.
917/30 had close to 1600 hp for 1800lbs i qualy trim... nuts! Can't remember who said this recently but a current test drive from a professional said it was the fastest way to get to the next corner. Anyone know the times of the qualies in 73 just to compare to last year lmp1 for schnitz and gargoyles?
Hmm, Goodyears or Hoosiers, made me do a double-take.
Red/Yellow-capped braided hoses are turbo oil drains. Someone needs to school me on the brass hex plugs on the intake plentums. There's something else there in the in-period photo. I had a 1:24th scale RC car with the L&M livery in the mid-late 70's. What an icon!
Its a shame this era of racing had to end. I will most likely never get to see these things get properly thashed around a track. Is todays equivalent the Audi R18 e-tron? And what where the red & yellow flexi hose's hanging off the back for?
@SuzyWallace If memory serves me correctly in the late 60's and early 70's Audi wasn't that big a company so they shared importers and distributors in the states such as Vasek Polak who bought and raced 917-10's after Penske moved to the 917-30
According to the times I could find on the Nurburgring in 1972 the 917/10 was timed at a 7min 36sec lap time on the rebuilt course. How different that is to now and whether or not it included the Grand Prix track I have no idea so it's hard to make a comparison.
A modern 997 GT3 will lap the ring minus the GP track in I think low 7min 30sec range so if the 71 course included the GP track and the 917 is clocking a 7min 36sec that is impressive to say the least.
My guess is the modern LMP1 car would destroy the 917 both in lap time and in an all out 24h race though. Bet the 917 is way more terrifying to drive :D
@Waxhaw Brad The plugs are likely for getting a look at the carbs without taking the intakes off. Some of the older photos look like the had some over-pressure knockouts, hard to see, but without intercoolers, if a wastegate hung, the first thing to go boom would be those manifolds.
@roeby There is no equivalent. Calling a modern LMP jokemobile a modern equivalent of a Can Am car is like calling a cafeteria the modern equivalent of a Roman orgy feast.
@roeby I'm guessing those are the oil feed lines (or drain lines) for the removed turbos. Just a guess though