993 Cup & RSR
The new 993 Cup 3.8 was developed at Porsche’s race department using the platform of their new 993 Carrera 2.
|Model||Type||Engine Type||Engine Size||HP Rating||Trans Type||Gears|
|993 Cup||993-360||M64/70||3.8 Litre||315||G50/30||6 Man|
|993 RSR||993-360||M64/75||3.8 Litre||325 to 350||G50/34||6 Man|
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993 Cup 3.8
The new 993 Cup 3.8 was developed at Porsche’s race department using the platform of their new 993 Carrera 2. Roland Kusmaul was responsible for the engineering of the new car, which was a genuine ‘no compromise’ race car.
The engine capacity was now 3.8 liters. The power output is 310bhp at 6100 rpm, which was an increase of 40bhp over the previous generation 911 Cup car. The engine rev limiter is set at 6900rpm, but Porsche used similar parts to the RSR engine valve gear and it could cope with 7800, or 7900 without breaking. This meant that the engine was low stressed for a race engine and incredibly reliable. The new 6-speed gearbox has very short shifts and was also enhanced for more reliability with steel synchromesh rings. The 3.8 Cup engine type number is M64/70 and gearbox type number is G50/30.
Porsche even managed to reduce the overall weight of their new 993 Cup car compared to the previous 964 Cup, with a further 20kg reduction. The 993 Cup weighs a mere 1100kg. The rear quarter side windows were now made from plexi-glass. With the exception of the windscreen the remaining glass was all thin lightweight glass. The body work is lighter with no side impact beams in the doors and aluminium bonnet. Inside the car there is no sound insulation, no carpets, no headlining, no power steering, no hand brake, no passenger seat, not even any heating system. The FIA approved Matter supplied roll cage not only makes the car meet the required safety standards, but makes the car very stiff for better chassis response.
The brakes for the 993 Cup car were also improved with large front and rear brake calipers and disks, the latest 5 channel ABS system with motorsport control unit tuned specifically for the slick tyres fitted to the car.
The new springs and dampers are much stiffer than the 964 Cup version, and the ride height of the 993 Cup car is set at 70mm lower than the 993 Carrera 2 it is based on.
993 Cup 3.8 RSR
The RSR 3.8 was developed by the Porsche motorsport department specifically to support Porsche customer race team entries in to International Endurance events like the American IMSA GT series and European GT series. Out of the box the RSR was intended to compete in 24hr endurance events like Daytona, Spa and Le Mans. Like the Cup car it is based the standard RSR equipment included full welded Matter rollcage, an alloy bonnet, a front strut brace, fully ball-jointed suspension, special front spoiler and adjustable rear wing, a single racing seat with harness belt, battery switch, and a fire extinguishing system.
The RSR specification was a set of further developments fitted to the RSR cars as standard. This included 2 way adjustable Bilstein suspension adjustable for bump and rebound settings, bolt on fender flares like the GT2 to allow much wider wheels, larger 380mm endurance front brakes as fitted to the GT2, driver adjustable front roll bar and the all important M64/75 RSR engine and G50/34 gearbox. As an optional extra a 100 liter Premier safety fuel cell was available.
The M64/75 type 3.8 RSR engine was an extensively reworked race bread engine with stronger lighter valve gear, rockers, high lift cams and special pistons & barrels. To maximize the performance the inlet plenum and exhaust manifolds were also thoroughly revised and mated to 6 individual throttle bodies. Power was delivered through a single-mass flywheel to a unique RSR six-speed Type G50/34 manual box.
There is some confusion as to which cars are actually RSR cars. This is because during 1996 Porsche started supplying Cup cars with an RSR engine for customers who wanted to race their cars in the various series running GT3 classes. However they were just standard Cup cars with an RSR engine. Some people refer to these cars, because they have an RSR engine. However for model year 1997 Porsche developed a complete RSR vehicle specification which had a ‘Z’ order option code of ‘20631 RSR Package Vehicle’. Only these cars are full correct 993 RSR’s. Porsche produced 30 for 1997 and 15 for 1998.
Strangely Porsche’s own records for some RSR’s state an engine type of M64/70, which is only a standard Cup engine. However this is not the case in reality. When the actual engine numbers are checked ‘ALL’ RSR’s were supplied with RSR engines, which are M64/75.
All 993 RSR engine numbers are of the following format 62P85nnn. The 6th digit denotes the year 7 or 8 for 1997 or 1998 respectively. The final 2 digits are the unique number for that engine. The RSR engines were supplied in 3 basic specification options, which can only be determined from checking which number range it falls between, as detailed below for 1997. We also have the information for 1998 on file.
62P85701 to 62P85715 Exhaust manifolds 40mm, Twin intake trumpet, No restrictor.
62P85716 to 62P85726 Exhaust manifolds 45mm, Restrictor 48.2mm.
62P85727 to 62P85730 Exhaust system with catalytic converters and muffler.
|993 Cup with RSR engine||20||20|