Bruce Anderson
Flat 6A few years ago my wife and I had a really great trip to Europe. We rented an Audi 80 and flogged it for over 7500 km all around Europe. Fortunately for part of the trip we got to drive a couple of Alois Ruf's cars, he even loaned us a car to use in a Ruf Club drivers school at the Hockenheimring. I have known Alois Ruf for several years and consider him to be a really good friend. Some time ago he extended an invitation for us to visit him when we were in Europe, so we were looking forward to visiting Ruf while we were in Europe earlier in 1984. The way our schedule worked out the time that we had originally planned to visit Ruf was at a time when there was a religious holiday, Corpus Christi, which just wouldn't work. Instead Ruf suggested a different time schedule and invited us to a Ruf Club driving school at Hockenheimring and arranged for us to participate in the school with one of his Ruf RCT (Ruf Carrera Turbo) 911s.
Normally the Ruf Club runs their drivers schools on the short course at Hockenheim and this was their first time to use the full long Grand Prix course at Hockenheim for one of the clubs driving schools. In the morning of the one day school we were broken up into groups based on our experience at Hockenheim and then taken to each corner and instructed on the proper line through the turn. The instructor would stand at the entrance, apex and then exit of each corner and watch every one of us take the turn and then call us all in and offer corrections to our lines or approaches to the turn. After lunch the groups were turned loose on the track for sessions of about twenty minutes each. There was enough track time to wear out all of the drivers, but not the cars and many people quit early and went home. At the end of the day they gave awards for performance in each of the groups based on the improvement during the day compared to where they started in the morning.
Stefan Roser who is a long time friend of Alois Ruf's and worked for Ruf at that time was giving the Ruf Club members and friends rides around the Hockenheim track in "Yellow Bird," the original CTR (Group C Turbo Ruf). Both the car and Stefan are spectacular. Alois Ruf calls Stefan Roser "sideways Stefan," and if you have ever seen the Ruf video "Faszination" which shows Stefan Roser driving "Yellow Bird" at Nürburgring you have an idea why Ruf calls him that and what the experience of riding with him might be like. I rode around Hockenheim with Stefan for several laps and had a great time and I will have a lot more respect for races that I see at the Hockenheim circuit now.
"Yellow Bird" was built in 1987 and is the car that we have all read about in Road & Track that won the shoot-out and beat all of the worlds fastest super cars, including the Porsche 959S. "Yellow Bird" ran 211.5 mph in this top speed shoot-out at the VW proving ground. This same car went even faster, 212.5 mph, at a subsequent event held on the Nardo Racetrack. In addition to the speed records "Yellow Bird" clocked 0-60 mph in 4 second and turned the quarter mile at 133.5 mph in 11.7 seconds.
"Yellow Bird" is a light weight construction 911 with a 469 horsepower twin turbo 911 based 3.4 liter engine. For the CTR Ruf uses his own intake manifold similar in design to the Carrera manifold, but larger in capacity with the special Digital Motronic Electronic (DME) fuel injection and ignition system that was originally developed for the Porsche 962 race cars used to control the fuel mixture and ignition timing. Instead of measuring the air flow like most electronic engine management systems do this system is a pressure sensing type system which uses throttle position, rpm, engine temperature and manifold pressure as input signals. This was the first of these high powered 911 turbo engines that really ran right and made a lot of horsepower. Since "Yellow Bird" was built many of the aftermarket tuners have been utilizing various different electronic engine management systems to greatly enhance the engine performance of the turbo and now that Porsche is finally abandoning the CIS fuel systems for their next generation 911 Turbo, which will be introduced next March, the engine management situation for these engines has come full circle.
Ruf Automobile GmbH has been certified by the German government as an original automobile manufacture 1981. In 1987 Ruf Automobile GmbH also became an approved manufacturer with the US authorities for safety and emissions (NHTSA and EPA). Five years ago Ruf GmbH employed 70 people in the various areas of the company, but the combination of improved efficiencies and the depressed world economy of the past few years have reduced their staff to 42 highly trained and skilled employees. Because of the soft world economy and unfavorable DM to Dollar exchange rates Ruf has not sold many of his cars in the US over the past few years, but he did have his RCT certified in 1994 and he plans to have his 993 BTR certified by next Spring.
Ruf said that he has built 28 CTR's from new bare chassis with no chassis numbers purchased from Porsche and that he has also built about the same number of CTR's by converting them from existing 3.2 Carreras. The cars built from new chassis have Ruf chassis numbers and the modified cars still have their original Porsche VIN number. It is still possible to have a CTR built by Ruf as a conversion, but there are no new chassis left.
A great number of the Ruf CTR owners use them primarily for track events and there were several at the Ruf Club driving school at Hockenheim. There was also one Ruf's customers yellow CTRs at the Ruf facility for service that I looked over very closely. The Yellow CTR at Ruf's had a built in roll cage that was probably the best roll cage installation that I have ever seen in a Porsche 911. The roll cage was very unobtrusive and did not protrude into the passenger compartment hardly at all. They had upholstered over the roll cage so that it blended into the interior, the carpeting and upholstery went over the bars of the roll cage as did the cars headliner. This car also had a larger 105 liter (27.7 gallon) fuel tank that Ruf Gmbh had made for them by the original equipment manufacture who makes them for Porsche. Because the wheels and tires used on the CTR are of run flat technology no spare tire is required, so the fuel tank is made larger by omitting the indentation that would normally accept the 911 collapsible spare tire. The run flat technology wheels are either the Dunlop Denloc system or the Asymmetrical Hump system, Ruf uses both. The yellow Ruf CTR at Ruf's facility also utilized a number of Kevlar parts to help reduce the weight of the car. The doors, front trunk lid, front fender and front and rear bumper were all made of Kevlar composite. The fit and finish of the body and Kevlar panels was exemplary, it was impossible to tell by looking that the car didn't have the standard Porsche steel panels. Ruf also offers aluminum doors hood and front fenders as an options to the standard steel and the more expensive Kevlar composite parts.
One of Ruf's US customers, Steve Beddor from Minnesota, has been competing in some of the US hill climbs for years with a four wheel drive version of the CTR and he had the fastest time at the Virginia City Hill Climb in Nevada, and then ran the July fourth Pikes Peak Hill climb in Colorado and placed second behind Jeff Zwart in another Porsche 911 in what they call the Open Class. Beddor also won several stages in One Lap of America and probably only failed to win the event overall because of an electrical problem in 1994. Ruf is not used to his cars being entered in open competition events and came over to the US himself to personally oversee the running of the Virginia City Hill Climb.
Ruf has worked closely with Bosch for a number of years refining their application of the Bosch Motronic system on the Ruf turbocharged engines until they have come up with these superbly powerful and wonderful running turbocharged engines. The problem has been to develop a system that would work with their high flow turbo engines with their high power outputs and catalytic converter systems. They have achieved their goals by modifying the same Bosch Motronic system that is used on the 964. They use the big Porsche intake manifold and remove the tuned crossover pipe and the second throttle butterfly. For the 964 version of the engine they replaced the air flow flapper box with the hot film mass air flow sensor, but now the 993 comes with a hot film mass flow sensor so this change is no longer necessary.
Ruf uses KKK turbochargers that they have made specifically for their engine applications. They also use the largest intercoolers that Porsche uses for cool air charge temperatures to improve both reliability and engine performance. They have developed their own camshafts for their engines which provide good power throughout the rpm range. They backdate the 993 version of the engine to use the older style non-hydraulic rocker arms and their camshafts. They use their own pistons to lower the compression ration to 8.0:1 to work with turbocharging. For improved oil cooling both the 964 and the 993 utilize a second x in the front on the same side as the air conditioner condenser on the cars equipped with air conditioner units.
The performance of these cars are wonderful and they still exceed the world emissions laws. The difference between the performance of the Ruf engines and the Porsche turbo engines using the truly old-fashioned CIS fuel injection system is staggering, these are without a doubt the best driving turbocharged cars that I have ever driven. The performance and throttle responses are almost comparable to normally aspirated cars, you will have to drive one to believe it. Based on my experience with these Ruf cars makes me sure that It will be nice when the new Porsche 911 turbo finally comes out next March and they replace their archaic CIS fuel injection system with a contemporary DME type system like Ruf has been using.
The Ruf engines utilize catalytic converters to meet or exceed all of the European emission requirements and the BTR (Group B Turbo Ruf) engine has also been approved in the US for the strict US emissions standards and they plan to certify their other models in the future so that all of the Ruf cars, conversions and engines will be legal and available in the US.
The Ruf RCT that I drove in the school was a modified 911RS with a Ruf turbocharged 3.6 liter RCT engine. This is a wonderful car, all that you would expect a real RS model from Porsche to be, but more with the additional power of the Ruf 370 hp emissions legal turbocharged engine. With the Motronic injection system the engine was amazingly flexible with a lot of low end power and very little turbo lag. The engine would pull really well from 1800 rpm. Ruf suggested that I try just driving in sixth gear only for one stint on the autobahn to judge the flexibility of the engine. I did what he suggested and found that the RCT had tremendous flexibility pulling well from 80 km (50 mph) to 300 km (186 mph) in sixth gear. There was still more at 300 km, but there just wasn't room to use it because of traffic.
A friend of mine in the Porsche Club of America, Professor Bob White, took this same car out with Helmuth Bott last fall and they ran this car against Bott's personal 959 and at the top end this car was actually faster than the 959 and both would exceed 200 mph. White based his technical presentations at the Porsche Club Tech Sessions this year on this and I think it was called something like "Performance! Perception, Fact and a Little Friction." His presentation pointed out that power isn't everything and that the better aerodynamics, or less drag, of the Ruf RCT was what made it faster than the more powerful Porsche 959. Ruf prefers to make his cars out of the narrow bodied cars over the Turbo bodied cars both because he prefers their looks and because they are easier to push through the air at these high speeds. The "Yellow Bird" while not really a narrow bodied car had Ruf's own rear fender flares which were really only about 2 inches wider then the narrow bodied cars and not the really big ugly rear flares of the Turbo Look cars.
When we drove back to Pfaffenhausen, the home of Ruf GmbH, from Hockenheim, with Alois Ruf, we took turns with him driving both the 911 RCT that I had driven in the school and a prototype for his new 993 BTR. The 993 has not yet been introduced to the world motor press, so my experience with this car was a preview of coming attractions. We drove at 250 to 280 km (155 to 174 mph) when traffic permitted with an occasional burst up to 300 km (186 mph) just so we could say that we had done it. The engine in the 993 BTR is actually more powerful than the RCT at a Ruf rated 400 hp. They use the same basic layout as they did with the RCT engines but because of the new heat exchangers that Porsche has used on the 993 engine they were able to increase the power to a Ruf rated 400 plus horsepower. After driving both the Ruf RCT and 993 BTR I am convinced that the Ruf horsepower ratings are very conservative compared to what we have grown used to in the US.
Because of the traffic conditions, we weren't able to go as fast with the 993 as we did with the RCT, but we did cruise for quite awhile at 250 to 280 km. (155 to 174 mph). This prototype is based on one of the Porsche factories first production cars and has all of the standard trim so it is quite a bit heavier than the RCT, yet the two cars seemed to have comparable autobahn performance. Ruf and I took turns driving both cars and we chased Ruf in both instances and were able to keep up with him in either car so they are comparable. They have made some changes to the suspension for the 993, but while I was there they were not done with their development work so additional refinements will be made before the cars is introduced to the press. They change the springs, to spring rates of their own design, they use larger sway bars and Bilstein shock absorbers tuned to match their other suspension changes. Ruf cars are typically lowered about 40 mm (1.6") and use larger stabilizers which reduce the body role angle and provide optimum handling without sacrificing the ride comfort by using really significantly stiffer spring rates to stiffen up the roll rates.
If it is possible to say that it is safe to drive at these speeds then these are certainly the cars to do it in. Both cars were incredibly stable and safe feeling at these speeds with a slight edge going to the 933 with its quieter and slightly softer ride. The trip to Pfaffenhausen was probably more fun for us than participating in the driving school at Hockenheim because we had never been able to drive this quickly on public roads and we have driven at a number of different tracks around the world.
In the past when we were in Europe and we would often ask people how far it was to somewhere that we were all going and they would answer not how far, but how long that it would take to get there, and then almost as if it were an after thought they would say in a "fast car." Until this trip I never really knew what they meant by a "fast car," but it always took me quite a bit longer to get to our destination than the suggested time. Well now I know what they meant by a "fast car."
All of Ruf's cars use their own six-speed transmission which use different gearing than Porsche does even in their new 993 with its six-speed transmission. The Ruf cars are geared for the increased power output and so that the engine can be kept on the boost in all driving conditions and so that they can achieve their top speed of over 200 mph. The Ruf six-speed transmissions also use the big Porsche Turbo ring and pinion.
Ruf uses lightweight construction options on all of his models to reduce the total vehicle weight In addition to the doors, hoods and fenders he reduces much of the superfluous interior and offers a choice of lightweight manually adjustable racing seats, or the RS bucket seats, light weight interior panels and manual window mechanisms. Lightweight structural bumper parts and thin glass windows may also be used to further reduce body weight. You may also order your Ruf without any undercoating or sound proofing materials for even more weight savings.
You can also go the other way with your Ruf as he allows luxury items as options as well. Examples of the Ruf luxury items include optional luxury sports seats, leather, on the seats, door panels, steering wheel, sun visor, headliner and safety roll cage and some of the normally carpeted surfaces. Electronic luxury items include a CD-Stereo system, a telephone and a mobile Fax machine. He will install air conditioners for hot climates, but he discourages the sun roof option, because he feel that they detract from the integrity of the car and just add squeaks and rattles to the otherwise solid car. I agree with him on the sun roof, I wish that Porsche would make it easier to buy cars with a delete sun roof option. In addition to Alois Ruf's complaints about the sun roof it ruins one of the best places on the car to polish for those who like to polish and admire there cars. Also if you use them they tend to screw up the headliners in the car.
Some of the features of the Ruf cars are not negotiable, for example the Ruf upgraded brake system is standard on all of his cars. The brake system uses larger vented rotors and calipers that have been increased in size to maintain their relationship with the performance potential of his cars. His new cars such as the RCT and the 993 BTR use the same large calipers as the red calipers that Porsche uses on their 3.6 turbo, these are the largest Brembo calipers for the Porsche cars. Ruf's calipers are still black in color even though they are the same large calipers used on the 3.6 Turbo, because he feels the red calipers are too obvious and pretentious. The six-speed transmissions are also standard equipment, but you may choose a five-speed as an option if you prefer. One of my favorite options on these cars proved to be Ruf's semi-automatic shift system, the optional electronic clutch system.(EKS) which provides the convenience of clutchless driving with out the loss of power normally associated with any of the other clutchless systems which utilize a torque converter.
When we were at Ruf's we drove their second 993 BTR prototype, which has his EKS (Electronische Kupplung System) or in plain English an Electronic Clutch System. Alois Ruf had told me about this system almost two years ago in January 1993 when we met at the Porsche clubs Thunder Tech in Tampa Florida. At the time he was very enthusiastic about the system and I must admit I was not overly impressed with the concept, because I found myself lumping it together with the Sportomatic and Tiptronic transmission of Porsche.
The Ruf cars with the EKS have no clutch pedal and are similar in operation to the transmissions used in the modern Formula 1 cars. The clutch operation is controlled by electronic signals from a computer controlling hydraulic control circuits. The system responds to several different sensors: a gas pedal sensor for throttle position, a torque sensor in the gearshift lever so that it knows when you want to shift, and engine and car speed sensors. From the signals from these different sensors the EKS computer decides when and how to engage or disengage the rather conventional single plate clutch through a hydraulic actuator that moves the clutch throw out bearing. The EKS system is manufactured by the Sachs company and Ruf was their first customer and has helped Sachs to develop the system. Sachs wanted a small manufacture to work with so that they could gain practical experience with the system before they went after a mass market. Saab will be the first large volume manufacture to use the EKS type system in a volume production car in the 1995 model year. Saab will use the system in the Saab 900SE turbo and they will call their version of the clutchless EKS car the Sensonic. I guess they are calling their version the Sensonic because it senses when you want to shift, and the systems do indeed do just that. I am not sure about the sonic part.
I had not really expected to be impressed with this system or this car using the system because I have already had some clutchless Porsche experience with both the Porsche Sportomatic and the Porsche Tiptronic. My wife had a 911 Sportomatic for about ten years in the seventies and early eighties and I really expected this to be more of the same. I have always felt that these clutchless transmissions like the Sportomatic and the Tiptronic serve a purpose and are nice to drive, but are usually difficult to defend in a macho conversation. Incidentally speaking of the Porsche Tiptronic the newest version is called Tiptronic S and has the shift controls on the steering wheel like some of the Formula 1 cars do, but it is still an automatic transmission with a torque converter. The new Porsche Tiptronic S has two rocker switches for shifting, one on each side of the top spokes on the steering wheel. To shift up you push upwards on either of the switches (labeled "+") to engage the next higher gear and to shift down you push downwards on the button (labeled "-") for downshifts. All of this is aimed at adding to the enjoyment of driving a Porsche. These steering wheel controls are supplemental to the Tiptronic's standard dual-range console. And Porsche says that this update can be retrofitted to the 1994 version of the 993 as well.
After I drove the Ruf 993 prototype with the EKS I was so impressed with the operation of this combination of an automatic clutch and a manual six-speed transmission that I would now be willing to try to defend it in one of those macho conversations. You can bet that if I can afford it that I will try one in the "Project 911" that I am building. You loose absolutely no performance, yet you don't have to bother with a clutch. Its operation is computer controlled and it is definitely more consistent than most drivers and I would guess a lot smarter than some, including me. I honestly didn't miss the clutch pedal at all and only poked at the clutchless floor once and that was one time when I pulled to a stop to photograph one of the cars.
The Ruf EKS clutch system has been available since the Spring of 1992. Sixty EKS cars have been built and sold already and most of the cars that Ruf is building now are delivered with this option. Porsche also offers the EKS clutch system and has already built 20 3.6 911 Turbos with the EKS clutch system using their own five-speed transmissions. Porsche says that unfortunately this system will not be available for cars in the US because it has not been approved and they are concerned about product liability in the US market. Ruf will make his cars available here in the US with the EKS clutch and don't count this option out.
Most people who try any of the Porches which don't have a clutch pedal will say things like "I would consider one if I was going to do any serious city driving in a Porsche on a daily basis" But it seems even the drivers who do have to drive in heavy traffic on a daily basis never do opt for the clutchless driving, I think that it must just be that macho thing. The car that Stephan Roser, who works for Ruf, drives to work is a red Ruf RCT with the EKS clutch system and the Ruf six-speed transmission. Stefan Roser says that he loves it and he can make it talk. He commutes From his home in Stuttgart to Pfaffenhausen each day which is about 170 km (105 miles) each way and makes the trip in a little over an hour from door to door. He said that he has let a lot of race drivers drive the cars with EKS and they have all said that they like them and would like a car with that system for their own street use.
There are no losses through a torque converter like there was with the Sportomatic and with the more contemporary Tiptronic automatic transmission because the EKS uses a clutch and does not have a torque converter. Even with the Tiptronic S's new trick steering wheel shift mechanism, I would still rather have Ruf's EKS system than the Tiptronic. The performance is improved because there is no clutch lag time. With the EKS you have both the performance and the fuel economy of the manual transmission. But you have the advantage of being able to shift as fast as you can move your hand and you don't have to worry about coordinating that with the movement of your left foot.
One thing that I particularly like about Ruf's EKS installation was the vertically reading indicator in the lower part of the speedometer which tells you which gear you are in. I still have a little trouble in cars with six speed transmissions when I am just cruising along talking with my passenger I forget what gear I am in and this shift indicator is a great help for this.
The EKS system is sophisticated and there are a number of potential advantages over a conventional clutch. The clutch engagement is more precise than we can do by ourselves, so we will have less clutch wear. You cannot abuse the clutch as a lazy driver might with a normal foot activated clutch. If you miss a shift the computer will protect the engine by not engaging the clutch. The EKS system provides all of the advantages of being able to enjoy shifting gears without a clutch pedal in stop-and-go traffic or in high speed conditions. It is sporty yet comfortable, with flawless clutch engagement.
You can start out in first or second gear, but the computer wont let you start out in third. If you miss a shift on a down shift the will not engage, so the EKS will save you and your engine from yourself.
Ruf was building their first production version of the 993 BTR from a bare 993 tub purchased from Porsche while we were there. The car is painted Ruf green, which I don't think was the greatest choice of colors, I would have rather seen it be a brighter color. The green Ruf car utilized a lot of light weight considerations and still ended up weighing 1360 kilograms (2998 lbs.) with a full tank of fuel. The 993s are quite a bit heavier than the 964s even though Porsche claims that they are not.
The 993 prototypes are really pretty, one is a dark metallic blue and the other is silver metallic. When we were there he had two additional cars that he was going to convert after he finished the first production car and they are the both bright colors, one was speed yellow and the other the new bright Riviera blue, both of these cars are right hand drive for Singapore customers. The Ruf 993 BTRs will also be available in the US as US legal cars in the Spring of 1995. The Ruf body changes on the 993 are limited to the addition of the large rear spoiler from the 3.6 Turbo and light weight doors for now, but surely other light weight panels will be developed. And Ruf said that they may have to develop a front spoiler in the future to achieve the balance at high speed that they want. They also use 18" wheels on both their RCT and the 993 BTR. The 964 RCT uses 8.5 x 18" front wheels with 345/40 ZR tires and 9.5 x 18" rear wheels with 265/35 ZR tires. The Turbo bodied cars that Ruf builds use 8.5 x 18" front wheels with 245/40 ZR tires and 10 x 18" rear wheels with 285/35 ZR tires. The 993 BTR uses wheels with a different offset that are 8.5 x 18" in the front with 245/40 ZR tires and 10 x 18" rear wheels with either 285/35 ZR tires or 275/35 ZR tires depending upon their tire maker.
We really enjoyed visiting Alois Ruf in Pfaffenhausen, he shared the Pfaffenhausen experience with us. The town of Pfaffenhausen is a tightly nit community with a population of about 2000 people. Ruf gave us the Pfaffenhausen equivalent of wining and dining us, he took us to a German Beer Tent where we had some of the wonderful local Storkenbrau beer, great music and beer tent food. There is probably no American equivalent to this experience, most of the town's people turn out for the Beer Tent at least one of the three or four nights that the tent is open. I asked Ruf what the occasion was and he said that it was to raise some money for the town's soccer team, but he said that they use any excuse to have a beer tent. The beer, music and food were great and it was a good experience for us, we had so much fun that we went back a second night.
For a little diversification from cars Ruf is building a hydroelectric plant in Turkheim, a neighboring town, to Pfaffenhausen. He jokingly says that if Alpina, the BMW tuner, can diversify into fine wines that he should be able to diversify into hydroelectric power plants. The motivation for this project is that it was something that has farther had tried to do before he passed away twenty years ago. At that time it was not politically correct to use hydroelectric power plants as they were building nuclear power plants all over Europe as the way of the future. Since that time the pendulum has swung the other direction and particularly since the Cherenoble (SP?) accident and the Nuclear power plants have been out of vogue. In fact now it is very popular to use natural means of power generation and the German government will subsidize part of the cost of developing natural power sources.
Ruf makes cars with single turbos and dual turbo and cars with both all-wheel-drive or rear-wheel-drive only and both Turbo look and narrow bodied cars. I still haven't driven a Ruf all wheel drive nor the Turbo look. I think that I would have to visit Alois Ruf once a month to experience all of the wonderful cars that he builds, but I was very pleased with the cars that I was able to experience in my all too short visit with the man who truly makes Porsches better. I loved the RCT, but make mine a 993 BTR with the EKS clutch system.
My wife and I just had a really great trip in Europe. We rented an Audi 80 and flogged it for over 7500 km all around Europe. Fortunately for part of the trip we got to drive a couple of Alois Ruf's cars, he even loaned us a car to use in a Ruf Club drivers school at the Hockenheimring. I have known Alois Ruf for several years and consider him to be a really good friend. Some time ago he extended an invitation for us to visit him when we were in Europe, so we were looking forward to visiting Ruf while we were in Europe earlier this summer. The way our schedule worked out the time that we had originally planned to visit Ruf was at a time when there was a religious holiday, Corpus Christi, which just wouldn't work. Instead Ruf suggested a different time schedule and invited us to a Ruf Club driving school at Hockenheimring and arranged for us to participate in the school with one of his Ruf RCT (Ruf Carrera Turbo) 911s.
Normally the Ruf Club runs their drivers schools on the short course at Hockenheim and this was their first time to use the full long Grand Prix course at Hockenheim for one of the clubs driving schools. In the morning of the one day school we were broken up into groups based on our experience at Hockenheim and then taken to each corner and instructed on the proper line through the turn. The instructor would stand at the entrance, apex and then exit of each corner and watch every one of us take the turn and then call us all in and offer corrections to our lines or approaches to the turn. After lunch the groups were turned loose on the track for sessions of about twenty minutes each. There was enough track time to wear out all of the drivers, but not the cars and many people quit early and went home. At the end of the day they gave awards for performance in each of the groups based on the improvement during the day compared to where they started in the morning.
Stefan Roser who is a long time friend of Alois Ruf's and now works for Ruf was giving the Ruf Club members and friends rides around the Hockenheim track in "Yellow Bird," the original CTR (Group C Turbo Ruf). Both the car and Stefan are spectacular. Alois Ruf calls Stefan Roser "sideways Stefan," and if you have ever seen the Ruf video "Faszination" which shows Stefan Roser driving "Yellow Bird" at Nürburgring you have an idea why Ruf calls him that and what the experience of riding with him might be like. I rode around Hockenheim with Stefan for several laps and had a great time and I will have a lot more respect for races that I see at Hockenheim now.
"Yellow Bird" was built in 1987 and is the car that we have all read about in Road & Track that won the shoot-out and beat all of the worlds fastest super cars, including the Porsche 959S. "Yellow Bird" ran 211.5 mph in this top speed shoot-out at the VW proving ground. This same car went even faster, 212.5 mph, at a subsequent event held on the Nardo Racetrack. In addition to the speed records "Yellow Bird" clocked 0-60 mph in 4 second and turned the quarter mile at 133.5 mph in 11.7 seconds.
"Yellow Bird" is a light weight construction 911 with a 469 horsepower twin turbo 911 based 3.4 liter engine. For the CTR Ruf uses his own intake manifold similar in design to the Carrera manifold, but larger in capacity with the special Digital Motronic Electronic (DME) fuel injection and ignition system that was originally developed for the Porsche 962 race cars used to control the fuel mixture and ignition timing. Instead of measuring the air flow like most electronic engine management systems do this system is a pressure sensing type system which uses throttle position, rpm, engine temperature and manifold pressure as input signals. This was the first of these high powered 911 turbo engines that really ran right and made a lot of horsepower. Since "Yellow Bird" was built many of the aftermarket tuners have been utilizing various different electronic engine management systems to greatly enhance the engine performance of the turbo and now that Porsche is finally abandoning the CIS fuel systems for their next generation 911 Turbo, which will be introduced next March, the engine management situation for these engines has come full circle.
Ruf Automobile GmbH has been certified by the German government as an original automobile manufacture 1981. In 1987 Ruf Automibile GmbH also became an approved manufacturer with the US authorities for safety and emissions (NHTSA and EPA). Five years ago Ruf GmbH employed 70 people in the various areas of the company, but the combination of improved efficiencies and the depressed world economy of the past few years have reduced their staff to 42 highly trained and skilled employees. Because of the soft world economy and unfavorable DM to Dollar exchange rates Ruf has not sold many of his cars in the US over the past few years, but he did have his RCT certified in 1994 and he plans to have his 993 BTR certified by next Spring.
Ruf said that he has built 28 CTR's from new bare chassis with no chassis numbers purchased from Porsche and that he has also built about the same number of CTR's by converting them from existing 3.2 Carreras. The cars built from new chassis have Ruf chassis numbers and the modified cars still have their original Porsche VIN number. It is still possible to have a CTR built by Ruf as a conversion, but there are no new chassis left.
A great number of the Ruf CTR owners use them primarily for track events and there were several at the Ruf Club driving school at Hockenheim. There was also one Ruf's customers yellow CTRs at the Ruf facility for service that I looked over very closely (See Photographs). The Yellow CTR at Ruf's had a built in roll cage that was probably the best roll cage installation that I have ever seen in a Porsche 911. The roll cage was very unobtrusive and did not protrude into the passenger compartment hardly at all. They had upholstered over the roll cage so that it blended into the interior (see photos), the carpeting and upholstery went over the bars of the roll cage as did the cars headliner. This car also had a larger 105 liter (27.7 gallon) fuel tank that Ruf had made for them by the original equipment manufacture who makes them for Porsche. Because the wheels and tires used on the CTR are of run flat technology no spare tire is required, so the fuel tank is made larger by omitting the indentation that would normally accept the 911 collapsible spare tire. The run flat technology wheels are either the Dunlop Denloc system or the Asymmetrical Hump system, Ruf uses both. The yellow Ruf CTR at Ruf's facility also utilized a number of Kevlar parts to help reduce the weight of the car. The doors, front trunk lid, front fender and front and rear bumper were all made of Kevlar composite. The fit and finish of the body and Kevlar panels was exemplary, it was impossible to tell by looking that the car didn't have the standard Porsche steel panels. Ruf also offers aluminum doors hood and front fenders as an options to the standard steel and the more expensive Kevlar composite parts.
One of Ruf's US customers, Steve Beddor from Minnesota, has been competing in some of the US hill climbs this year with a four wheel drive version of the CTR and he had the fastest time at the Virginia City Hill Climb in Nevada, and then ran the July fourth Pikes Peak Hill climb in Colorado and placed second behind Jeff Zwart in another Porsche 911 in what they call the Open Class. Beddor also won several stages in this years One Lap of America and probably only failed to win the event overall because of an electrical problem. Ruf is not used to his cars being entered in open competition events and came over to the US himself to personally oversee the running of the Virginia City Hill Climb.
Ruf has worked closely with Bosch for a number of years refining their application of the Bosch Motronic system on the Ruf turbocharged engines until they have come up with these superbly powerful and wonderful running turbocharged engines. The problem has been to develop a system that would work with their high flow turbo engines with their high power outputs and catalytic converter systems. They have achieved their goals by modifying the same Bosch Motronic system that is used on the 964. They use the big Porsche intake manifold and remove the tuned crossover pipe and the second throttle butterfly. For the 964 version of the engine they replaced the air flow flapper box with the hot film mass air flow sensor, but now the 993 comes with a hot film mass flow sensor so this change is no longer necessary.
Ruf uses KKK turbochargers that they have made specifically for their engine applications. They also use the largest intercoolers that Porsche uses for cool air charge temperatures to improve both reliability and engine performance. They have developed their own camshafts for their engines which provide good power throughout the rpm range. They backdate the 993 version of the engine to use the older style non-hydraulic rocker arms and their camshafts. They use their own pistons to lower the compression ration to 8.0:1 to work with turbocharging. For improved oil cooling both the 964 and the 993 utilize a second x in the front on the same side as the air conditioner condenser on the cars equipped with air conditioner units.
The performance of these cars are wonderful and they still exceed the world emissions laws. The difference between the performance of the Ruf engines and the Porsche turbo engines using the truly old-fashioned CIS fuel injection system is staggering, these are without a doubt the best driving turbocharged cars that I have ever driven. The performance and throttle responses are almost comparable to normally aspirated cars, you will have to drive one to believe it. Based on my experience with these Ruf cars makes me sure that It will be nice when the new Porsche 911 turbo finally comes out next March and they replace their archaic CIS fuel injection system with a contemporary DME type system like Ruf has been using.
The Ruf engines utilize catalytic converters to meet or exceed all of the European emission requirements and the BTR (Group B Turbo Ruf) engine has also been approved in the US for the strict US emissions standards and they plan to certify their other models in the future so that all of the Ruf cars, conversions and engines will be legal and available in the US.
The Ruf RCT that I drove in the school was a modified 911RS with a Ruf turbocharged 3.6 liter RCT engine. This is a wonderful car, all that you would expect a real RS model from Porsche to be, but more with the additional power of the Ruf 370 hp emissions legal turbocharged engine. With the Motronic injection system the engine was amazingly flexible with a lot of low end power and very little turbo lag. The engine would pull really well from 1800 rpm. Ruf suggested that I try just driving in sixth gear only for one stint on the autobahn to judge the flexibility of the engine. I did what he suggested and found that the RCT had tremendous flexibility pulling well from 80 km (50 mph) to 300 km (186 mph) in sixth gear. There was still more at 300 km, but there just wasn't room to use it because of traffic.
A friend of mine in the Porsche Club of America, Professor Bob White, took this same car out with Helmuth Bott last fall and they ran this car against Bott's personal 959 and at the top end this car was actually faster than the 959 and both would exceed 200 mph. White based his technical presentations at the Porsche Club Tech Sessions this year on this and I think it was called something like "Performance! Perception, Fact and a Little Friction." His presentation pointed out that power isn't everything and that the better aerodynamics, or less drag, of the Ruf RCT was what made it faster than the more powerful Porsche 959. Ruf prefers to make his cars out of the narrow bodied cars over the Turbo bodied cars both because he prefers their looks and because they are easier to push through the air at these high speeds. The "Yellow Bird" while not really a narrow bodied car had Ruf's own rear fender flares which were really only about 2 inches wider then the narrow bodied cars and not the really big ugly rear flares of the Turbo Look cars.
When we drove back to Pfaffenhausen, the home of Ruf GmbH, from Hockenheim, with Alois Ruf, we took turns with him driving both the 911 RCT that I had driven in the school and a prototype for his new 993 BTR. The 993 has not yet been introduced to the world motor press, so my experience with this car was a preview of coming attractions. We drove at 250 to 280 km (155 to 174 mph) when traffic permitted with an occasional burst up to 300 km (186 mph) just so we could say that we had done it. The engine in the 993 BTR is actually more powerful than the RCT at a Ruf rated 400 hp. They use the same basic layout as they did with the RCT engines but because of the new heat exchangers that Porsche has used on the 993 engine they were able to increase the power to a Ruf rated 400 plus horsepower. After driving both the Ruf RCT and 993 BTR I am convinced that the Ruf horsepower ratings are very conservative compared to what we have grown used to in the US.
Because of the traffic conditions, we weren't able to go as fast with the 993 as we did with the RCT, but we did cruise for quite awhile at 250 to 280 km. (155 to 174 mph). This prototype is based on one of the Porsche factories first production cars and has all of the standard trim so it is quite a bit heavier than the RCT, yet the two cars seemed to have comparable autobahn performance. Ruf and I took turns driving both cars and we chased Ruf in both instances and were able to keep up with him in either car so they are comparable. They have made some changes to the suspension for the 993, but while I was there they were not done with their development work so additional refinements will be made before the cars is introduced to the press. They change the springs, to spring rates of their own design, they use larger sway bars and Bilstein shock absorbers tuned to match their other suspension changes. Ruf cars are typically lowered about 40 mm (1.6") and use larger stabilizers which reduce the body role angle and provide optimum handling without sacrificing the ride comfort by using really significantly stiffer spring rates to stiffen up the roll rates.
If it is possible to say that it is safe to drive at these speeds then these are certainly the cars to do it in. Both cars were incredibly stable and safe feeling at these speeds with a slight edge going to the 933 with its quieter and slightly softer ride. The trip to Pfaffenhausen was probably more fun for us than participating in the driving school at Hockenheim because we had never been able to drive this quickly on public roads and we have driven at a number of different tracks around the world.
In the past when we were in Europe and we would often ask people how far it was to somewhere that we were all going and they would answer not how far, but how long that it would take to get there, and then almost as if it were an after thought they would say in a "fast car." Until this trip I never really knew what they meant by a "fast car," but it always took me quite a bit longer to get to our destination than the suggested time. Well now I know what they meant by a "fast car."
All of Ruf's cars use their own six-speed transmission which use different gearing than Porsche does even in their new 993 with its six-speed transmission. The Ruf cars are geared for the increased power output and so that the engine can be kept on the boost in all driving conditions and so that they can achieve their top speed of over 200 mph. The Ruf six-speed transmissions also use the big Porsche Turbo ring and pinion.
Ruf uses lightweight construction options on all of his models to reduce the total vehicle weight In addition to the doors, hoods and fenders he reduces much of the superfluous interior and offers a choice of lightweight manually adjustable racing seats, or the RS bucket seats, light weight interior panels and manual window mechanisms. Lightweight structural bumper parts and thin glass windows may also be used to further reduce body weight. You may also order your Ruf without any undercoating or sound proofing materials for even more weight savings.
You can also go the other way with your Ruf as he allows luxury items as options as well. Examples of the Ruf luxury items include optional luxury sports seats, leather, on the seats, door panels, steering wheel, sun visor, headliner and safety roll cage and some of the normally carpeted surfaces. Electronic luxury items include a CD-Stereo system, a telephone and a mobile Fax machine. He will install air conditioners for hot climates, but he discourages the sun roof option, because he feel that they detract from the integrity of the car and just add squeaks and rattles to the otherwise solid car. I agree with him on the sun roof, I wish that Porsche would make it easier to buy cars with a delete sun roof option. In addition to Alois Ruf's complaints about the sun roof it ruins one of the best places on the car to polish for those who like to polish and admire there cars. Also if you use them they tend to screw up the headliners in the car.
Some of the features of the Ruf cars are not negotiable, for example the Ruf upgraded brake system is standard on all of his cars. The brake system uses larger vented rotors and calipers that have been increased in size to maintain their relationship with the performance potential of his cars. His new cars such as the RCT and the 993 BTR use the same large calipers as the red calipers that Porsche uses on their 3.6 turbo, these are the largest Brembo calipers for the Porsche cars. Ruf's calipers are still black in color even though they are the same large calipers used on the 3.6 Turbo, because he feels the red calipers are too obvious and pretentious. The six-speed transmissions are also standard equipment, but you may choose a five-speed as an option if you prefer. One of my favorite options on these cars proved to be Ruf's semi-automatic shift system, the optional electronic clutch system.(EKS) which provides the convenience of clutchless driving with out the loss of power normally associated with any of the other clutchless systems which utilize a torque converter.
When we were at Ruf's we drove their second 993 BTR prototype, which has his EKS (Electronische Kupplung System) or in plain English an Electronic Clutch System. Alois Ruf had told me about this system almost two years ago in January 1993 when we met at the Porsche clubs Thunder Tech in Tampa Florida. At the time he was very enthusiastic about the system and I must admit I was not overly impressed with the concept, because I found myself lumping it together with the Sportomatic and Tiptronic transmission of Porsche.
The Ruf cars with the EKS have no clutch pedal and are similar in operation to the transmissions used in the modern Formula 1 cars. The clutch operation is controlled by electronic signals from a computer controlling hydraulic control circuits. The system responds to several different sensors: a gas pedal sensor for throttle position, a torque sensor in the gearshift lever so that it knows when you want to shift, and engine and car speed sensors. From the signals from these different sensors the EKS computer decides when and how to engage or disengage the rather conventional single plate clutch through a hydraulic actuator that moves the clutch throw out bearing. The EKS system is manufactured by the Sachs company and Ruf was their first customer and has helped Sachs to develop the system. Sachs wanted a small manufacture to work with so that they could gain practical experience with the system before they went after a mass market. Saab will be the first large volume manufacture to use the EKS type system in a volume production car in the 1995 model year. Saab will use the system in the Saab 900SE turbo and they will call their version of the clutchless EKS car the Sensonic. I guess they are calling their version the Sensonic because it senses when you want to shift, and the systems do indeed do just that. I am not sure about the sonic part.
I had not really expected to be impressed with this system or this car using the system because I have already had some clutchless Porsche experience with both the Porsche Sportomatic and the Porsche Tiptronic. My wife had a 911 Sportomatic for about ten years in the seventies and early eighties and I really expected this to be more of the same. I have always felt that these clutchless transmissions like the Sportomatic and the Tiptronic serve a purpose and are nice to drive, but are usually difficult to defend in a macho conversation. Incidentally speaking of the Porsche Tiptronic the newest version is called Tiptronic S and has the shift controls on the steering wheel like some of the Formula 1 cars do, but it is still an automatic transmission with a torque converter. The new Porsche Tiptronic S has two rocker switches for shifting, one on each side of the top spokes on the steering wheel. To shift up you push upwards on either of the switches (labeled "+") to engage the next higher gear and to shift down you push downwards on the button (labeled "-") for downshifts. All of this is aimed at adding to the enjoyment of driving a Porsche. These steering wheel controls are supplemental to the Tiptronic's standard dual-range console. And Porsche says that this update can be retrofitted to the 1994 version of the 993 as well.
After I drove the Ruf 993 prototype with the EKS I was so impressed with the operation of this combination of an automatic clutch and a manual six-speed transmission that I would now be willing to try to defend it in one of those macho conversations. You can bet that if I can afford it that I will try one in the "Project 911" that I am building. You loose absolutely no performance, yet you don't have to bother with a clutch. Its operation is computer controlled and it is definitely more consistent than most drivers and I would guess a lot smarter than some, including me. I honestly didn't miss the clutch pedal at all and only poked at the clutchless floor once and that was one time when I pulled to a stop to photograph one of the cars.
The Ruf EKS clutch system has been available since the Spring of 1992. Sixty EKS cars have been built and sold already and most of the cars that Ruf is building now are delivered with this option. Porsche also offers the EKS clutch system and has already built 20 3.6 911 Turbos with the EKS clutch system using their own five-speed transmissions. Porsche says that unfortunately this system will not be available for cars in the US because it has not been approved and they are concerned about product liability in the US market. Ruf will make his cars available here in the US with the EKS clutch and don't count this option out.
Most people who try any of the Porches which don't have a clutch pedal will say things like "I would consider one if I was going to do any serious city driving in a Porsche on a daily basis" But it seems even the drivers who do have to drive in heavy traffic on a daily basis never do opt for the clutchless driving, I think that it must just be that macho thing. The car that Stephan Roser, who works for Ruf, drives to work is a red Ruf RCT with the EKS clutch system and the Ruf six-speed transmission. Stefan Roser says that he loves it and he can make it talk. He commutes From his home in Stuttgart to Pfaffenhausen each day which is about 170 km (105 miles) each way and makes the trip in a little over an hour from door to door. He said that he has let a lot of race drivers drive the cars with EKS and they have all said that they like them and would like a car with that system for their own street use.
There are no losses through a torque converter like there was with the Sportomatic and with the more contemporary Tiptronic automatic transmission because the EKS uses a clutch and does not have a torque converter. Even with the Tiptronic S's new trick steering wheel shift mechanism, I would still rather have Ruf's EKS system than the Tiptronic. The performance is improved because there is no clutch lag time. With the EKS you have both the performance and the fuel economy of the manual transmission. But you have the advantage of being able to shift as fast as you can move your hand and you don't have to worry about coordinating that with the movement of your left foot.
One thing that I particularly like about Ruf's EKS installation was the vertically reading indicator in the lower part of the speedometer which tells you which gear you are in. I still have a little trouble in cars with six speed transmissions when I am just cruising along talking with my passenger I forget what gear I am in and this shift indicator is a great help for this.
The EKS system is sophisticated and there are a number of potential advantages over a conventional clutch. The clutch engagement is more precise than we can do by ourselves, so we will have less clutch wear. You cannot abuse the clutch as a lazy driver might with a normal foot activated clutch. If you miss a shift the computer will protect the engine by not engaging the clutch. The EKS system provides all of the advantages of being able to enjoy shifting gears without a clutch pedal in stop-and-go traffic or in high speed conditions. It is sporty yet comfortable, with flawless clutch engagement.
You can start out in first or second gear, but the computer wont let you start out in third. If you miss a shift on a down shift the will not engage, so the EKS will save you and your engine from yourself.
Ruf was building their first production version of the 993 BTR from a bare 993 tub purchased from Porsche while we were there. The car is painted Ruf green, which I don't think was the greatest choice of colors, I would have rather seen it be a brighter color. The green Ruf car utilized a lot of light weight considerations and still ended up weighing 1360 kilograms (2998 lbs.) with a full tank of fuel. The 993s are quite a bit heavier than the 964s even though Porsche claims that they are not.
The 993 prototypes are really pretty, one is a dark metallic blue and the other is silver metallic. When we were there he had two additional cars that he was going to convert after he finished the first production car and they are the both bright colors, one was speed yellow and the other the new bright Riviera blue, both of these cars are right hand drive for Singapore customers. The Ruf 993 BTRs will also be available in the US as US legal cars in the Spring of 1995.
The Ruf body changes on the 993 are limited to the addition of the large rear spoiler from the 3.6 Turbo and light weight doors for now, but surely other light weight panels will be developed. And Ruf said that they may have to develop a front spoiler in the future to achieve the balance at high speed that they want. They also use 18" wheels on both their RCT and the 993 BTR. The 964 RCT uses 8.5 x 18" front wheels with 345/40 ZR tires and 9.5 x 18" rear wheels with 265/35 ZR tires. The Turbo bodied cars that Ruf builds use 8.5 x 18" front wheels with 245/40 ZR tires and 10 x 18" rear wheels with 285/35 ZR tires. The 993 BTR uses wheels with a different offset that are 8.5 x 18" in the front with 245/40 ZR tires and 10 x 18" rear wheels with either 285/35 ZR tires or 275/35 ZR tires depending upon their tire maker.
We really enjoyed visiting Alois Ruf in Pfaffenhausen, he shared the Pfaffenhausen experience with us. The town of Pfaffenhausen is a tightly nit community with a population of about 2000 people. Ruf gave us the Pfaffenhausen equivalent of wining and dining us, he took us to a German Beer Tent where we had some of the wonderful local Storkenbrau beer, great music and beer tent food. There is probably no American equivalent to this experience, most of the town's people turn out for the Beer Tent at least one of the three or four nights that the tent is open. I asked Ruf what the occasion was and he said that it was to raise some money for the town's soccer team, but he said that they use any excuse to have a beer tent. The beer, music and food were great and it was a good experience for us, we had so much fun that we went back a second night.
For a little diversification from cars Ruf is building a hydroelectric plant in Turkheim, a neighboring town, to Pfaffenhausen. He jokingly says that if Alpina, the BMW tuner, can diversify into fine wines that he should be able to diversify into hydroelectric power plants. The motivation for this project is that it was something that has farther had tried to do before he passed away twenty years ago. At that time it was not politically correct to use hydroelectric power plants as they were building nuclear power plants all over Europe as the way of the future. Since that time the pendulum has swung the other direction and particularly since the Cherenoble accident and the Nuclear power plants have been out of vogue. In fact now it is very popular to use natural means of power generation and the German government will subsidize part of the cost of developing natural power sources.
Ruf makes cars with single turbos and dual turbo and cars with both all-wheel-drive or rear-wheel-drive only and both Turbo look and narrow bodied cars. I still haven't driven a Ruf all wheel drive nor the Turbo look. I think that I would have to visit Alois Ruf once a month to experience all of the wonderful cars that he builds, but I was very pleased with the cars that I was able to experience in my all too short visit with the man who truly makes Porsches better. I loved the RCT, but make mine a 993 BTR with the EKS clutch system.
