The 1,875-Horsepower Porsche SR-17: My #WanganCarChallenge Entry

He-hey, everybody! It’s me, Mickey Mouse! I’m glad to be posting here today, especially because I’m participating in a #BuildPost challenge that MR2Maniac started. In this challenge, the goal is to build a car that’s destined to race at speeds of 160 miles per hour and beyond as a member of the Mid Night Club.

Now, where did I start?

Starting Point: Porsche 917-032

The Porsche 917 is the ideal race car. With a lightweight chassis, twelve cylinders mounted midship, massive rear tires, state-of-the-art innovations, and sleek aerodynamics, it was revolutionary in a time when race cars were increasingly reliant on science’s solidifying principles. After struggling in 1969, it took root in the World Sportscar Championship of 1970, dominating it and allowing Porsche to win its first Le Mans race. Next year, the 917 continued dominating, bringing another Le Mans trophy back to Stuttgart-Zuffenhausen. With a regulation change that reduced the maximum displacement for sports cars to 3.0 L in 1972, the 917 transitioned to Can-Am, dominating that series first as the 917/10 and then as the 917/30.

In other words, finding a 917 almost always guarantees success. For this challenge, I found one, 917-032. There are people that say it was scrapped after it was tested, but I was able to find the car’s unscathed space frame. Every body panel and instrument were nowhere to be found, but the interior was still present. The only thing I did to it were converting the suspension to pushrods and adjusting the suspension; other than that and some cleaning, I left the chassis as it was.

It was at this point that I knew restoring it would be a challenge worth tackling.

Body: Porsche 917 Langheck

The primary goal of a race at Wangan is to make every other car look like its going backwards; since this freeway is primarily straight, the top speed is paramount for its success. To assist it, it needs the long-tailed 917’s body, which was built for greater top speeds at tracks with larger straights (such as Le Mans).

Since I couldn’t find an original body shell, I had to fabricate a new one from carbon fiber, making the fenders wider than before. As for the ventilation, I merged both the Kurzheck and Langheck’s designs together to get as much cooling as possible, including six NACA ducts, a roof scoop, and a rear hood scoop. To stay planted on the asphalt, I appended the front lip from a 919, the rear diffuser from a 911 RSR, and a double-decker rear wing from a 962. In total, it should weigh 1,946 pounds. Concerning its colors, I wouldn’t paint it in order to save weight, having the dark fibers exposed, but I would include subtle red accents that follow the car’s body lines.

Engine: Porsche-Derived Flat-12

The car may look fast, but with cars that are making upwards of 600 horsepower, it’s going to need a major force of propulsion in the form of a whistling, snarling, and howling flat-twelve like its Can-Am relatives. I tried to find an original Type 912, but I had no luck. Instead, I found the schematics for the 930’s 3.0 L engine.

The final result was virtually unrelated to its starting point. The bore and stroke were set to 92.0 millimeters and 75.2 millimeters respectively, with the block fashioned from magnesium and the dual overhead camshaft heads crafted from aluminum silicon. A billet crankshaft and billet connecting rods were implemented while the pistons were leightweight forged units. Once two of these engines were made, I combined them into one sixty-valve, water-cooled unit capable of revving to 8,500 RPM. With the fuel being injected directly, I continued with the six-liter unit by supplying it with two titanic turbochargers shoving 2.88 bars (41.77 PSI) of boost into the power plant.

With these, the engine spews 1,875 horsepower and 1,474 lb-ft of torque.

Wheels and Tires: Magnesium 917 Wheels and Michelin Experimental Compounds

Those are some large numbers for this car, having a power figure that is over three times that of other “warriors of the Wangan” like the Blackbird 911 and the Devil Z. However, they do not guarantee that the car will be able to break any records; the tires and wheels guarantee that. They are any car’s vital link to the road, and for a car like this, it needs sticky, strong, and solid tires to ensure it flies on the freeway.

There were a few people I knew that had direct connections to Bibendum, the Michelin Man himself. Fortunately, these people gave me a direct line of communication to him, and upon speaking to him about what I needed, he assembled a highly-specialized team of engineers to develop a set of tires specifically made for this car.

I cannot share many of the details about them, but the front tires are 345 millimeters wide while the rear tires are 435 millimeters wide. In both cases, they wrap black, sixteen-inch wheels fabricated from magnesium in the exact manner as the 917’s wheels. With these tires, the car can take off to sixty miles per hour in under 2.0 seconds, blast through the quarter mile in under 8.50 seconds, and soar past a standing kilometer in under 15.20 seconds; to bring the car in for a landing, Brembo carbon-ceramic brakes are used in tandem with Hawk track-approved brake pads and red brake calipers.

Transmission: Reinforced Tremec T56 Magnum Close-Ratio Six-Speed Manual

Another important component in these figures is the transmission. To make the car capable of reaching approximately 302 miles per hour in its lowest-downforce setup, a transmission that could withstand the immense torque while supplying lagless power was needed. Inside the car, the shifter would appear to the right of the right-mounted seat with a short throw, a balsa knob, and a gated shifter. Underneath that, it would need to be lightning-fast and rock-strong.

I was searching for a suitable transmission for a long time, having gone with Getrag for one certain Beetle, but this time, I chose the Tremec T56 Magnum. It needed tons of reinforcement because in its stock form, it can only handle 700 lb-ft of torque, less than half of what was needed. After reinforcing it, I decreased the six ratios in order to reach a higher top speed, requiring me to also adjust the final drive a bit. Upon finishing my work with it, I mounted the transmission and got the stick to sprout in its original position.

Interior: Stripped to the Bare Essentials

The shifter is light for good reason: any and all redundant weight must be removed in a purpose-built car like this. A lighter weight will, to paraphrase Colin Chapman, make one faster everywhere; while the freeway in question is predominantly straight, I’ll need the handling for where the road curves. At speeds well above 240 miles per hour, an accident would be catastrophic. To reduce the likelihood of this, the handling must be improved through a combination of proper suspension tuning, downforce, sticky tires, and light weight.

Why must one need a radio when there is a twelve-cylinder orchestra sitting right behind the driver? There is no radio, but there is one black Recaro Profi racing seat, a black tachometer, speedometer, oil pressure gauge, and boost gauge, a Momo FWM/02 racing wheel, a red Sparco racing harness, and an FIA-approved, titanium, hand-built roll cage. With these critical weight savings, the 917 can dominate public roads like the Wangan route like its brethren did in sportscar racing and Can-Am.

Thank you for reading my #BlogPost! What do you think of my build? If you want to submit your own Mid Night Club build for a car, please post it with the hashtag #WanganCarChallenge; I look forward to seeing everybody else’s cars!