Porsche Engineering Magazine...because Porsche Engineering works wherethesetwoareasmeet. The joint knowledge of Porsche Engi-neering converges in Weissach – and yetitisgloballyavailable.Ofcourse,also

Edition 1/2008

Porsche Engineering Magazine

The Hardware LabThe highest standard for customers

Testing, measuring, analyzingOptimization of vehicle drivetrains

The 911 GT2Performance redefined

The engine of the Porsche 917A complete work of art with 1,100 bhp

80754_porsche_01_03_GB:80754_porsche_01_03_GB 15.04.2008 11:56 Uhr Seite 1

optimized to customer specificationsusing proven measurement and analysismethods. Whether you are steering yourPorsche through the urban jungle ofTokyo or cruising the frozen expansesof Alaska – no problem for your engineand transmission. Also, advanced com-puter technologies enable us to shortenengine development times significantly.We will present the development of theintake port as an example.

Qualified networks of technicians andengineers for the right ideas form thebasis for the development work ofPorsche Engineering. Take a peek behindthe scenes of a specialty department:our Hardware Lab.

Did you ever hear, by the way, about the“zero” hour of the 911? Wait and see.

Follow us on a journey through our de-velopment work and experience ouridea of performance close-up.

We wish you a pleasant read.

The Editorial Staff

Coming up with good ideas is one thing. But what is just

as important is finding new ways to implement them.

That’s what we do well. With innovative approaches and a

passion for our work, Porsche Engineering achieves peak

performance every day.

2

Dear Readers:

As times change, not only do the expec-tations of customer development change,but the demands on the vehicles in-crease as well. You know that these de-mands are coupled with performance.But you might not know the high-per-formance technology behind them. Lessfuel consumption, lighter-weight materi-als, fast implementation – the demandsare ever-growing.

In this issue, you can read all about ourwork on improving performance.

Enter the fascinating world of the GT2,the 911 series production vehicle withthe most powerful engine of its time.530 bhp – a mix of aerodynamic design,innovative technology, and incrediblepower. Let your mind travel in a PorscheCayenne S Transsyberia. And remem-ber last issue's cover photo? The leg-endary engine of the Porsche 917. In1973, its whopping 1,100 bhp providedenough thrust to leave the competitionin the dust.

Our computers have to be just as power-ful. Today, vehicle drivetrains can be

Editorial


Contents

3

Contents

NewsAbout Porsche Engineering

4

The new 911 GT2With new developments, now at 530 bhp

5

8

10

13

16

The engine of the Porsche 917A complete work of art with 1,100 bhp

Intake port developmentShorter development times thanks toadvanced computer technology

Optimization of vehicle drivetrainsAdvanced measurement and analysis methodsfor engine and transmission

Cayenne S TranssyberiaSpecial model for the most extremeoutdoor situations

20The Hardware LabTailored solutions for demanding customers

22911How the sports car got its name


At Porsche Engineering, engineers workfor you meticulously on new, unusualideas for vehicles and industrial products.Upon request from automotive manufac-turers and suppliers, we develop a varietyof solutions – ranging from the design ofindividual components, through the lay-out of complex modules, to the planningand implementation of complete vehicledevelopments including management ofthe run-up to production. What makes itspecial is that all this is done with theexpertise of a series manufacturer.

Does your company need an experiencedautomotive developer for your project?

News

4

About Porsche Engineering

Or would you prefer a specialized systemdeveloper? We offer our customers both –because Porsche Engineering workswhere these two areas meet.

The joint knowledge of Porsche Engi-neering converges in Weissach – andyet it is globally available. Of course, alsodirectly at your site. Regardless of wherewe work, we always bring a piece ofPorsche Engineering with us. If youwould like to learn more about us,please request our image brochure byemail:

[email protected]

Stuttgart

Dr. Ing. h.c. F. Porsche AG, Stuttgart, andCzech Technical University in Prague(CTU) have presented the “Porsche Engi-neering Award” for the third time. At theDevelopment Center in Weissach, Wolf-gang Dürheimer, Development Directorof Porsche, presented awards to threegraduates of CTU for their outstandingfinal theses. The first prize went toThomas Dynybyl (24), who investigatedthe subjects of cylinder cut-off systemsand downsizing in particular in his work“Reversible Engines”. In explaining itschoice, the jury, which was composed ofrepresentatives of Porsche and of CTU,referred to the special importance of in-novative engine concepts to the auto-mobile industry in order to be able to

meet future legal requirements. Otherprizewinners were Denis Waraus (25)and Lukas Sojka (25). All three winnersreceive a cash prize and an invitation tovisit the Development Center. In addi-tion, the winner of the first place is be-ing offered a doctorate position atPorsche Engineering Services s.r.o. inPrague.

Porsche and CTU have been working to-gether in the field of technical calcula-tion and simulation since 1996. ThePorsche Engineering Award has beenpresented each year since 2006 for thethree best final theses of the studentsof the Czech Technical University inPrague. The prize is intended to furthercement the relationship between CTUand Porsche AG.

Porsche honors graduates of Czech TechnicalUniversity, Prague.


5

Complete vehicle 911 GT2

With a power boost of 50 bhp comparedwith the engine of the 911 Turbo, the new911 GT2 is the most powerful 911 pro-duction vehicle of its time. Impressive pre-cision work quickens the heartbeat of anyengineer. Striving for efficient perfor-mance has always been the goal of thedevelopment work of Porsche. But howcan an almost perfect sports car be evenfurther optimized?

Resistance is futile. Highlights thatmake history.

The sophisticated aerodynamics in combi-nation with the extremely sporty suspen-sion and an engine output of 390 kW(530 bhp) give the 911 GT2 driving per-

Performance redefined – the new 911 GT2

formance that is second to none. With apower-to-weight ratio of 3.69 kilograms(8 lb) per kilowatt, the rear-drive GT2rockets from 0 to 100 km/h (63 mph)in 3.7 seconds.

The increase in power compared with thecurrent Porsche 911 Turbo is achievedmainly by a revised turbocharger withflow-optimized turbine and a larger com-pressor, as well as a complete redesignof the expansion intake system. The newlydesigned titanium rear silencer with re-duced flow resistance also adds to this.

Turn the page for our detailed descrip-tion of the special features of the expan-sion intake system.


The expansion intake system of thenew 911 GT2 is an enhancement of theexisting turbo engines. The unique andspecial feature is its operating principle,which has revolutionized existing pro-cesses. Like a traditional intake mani-fold for 6-cylinder Boxer engines, theexpansion intake system consists of adistributor pipe, two accumulators andsix individual intake ports. The decisiveand revolutionary approach is reflectedin the new geometric dimensions of thedistributor pipe and the individual intakeports. Compared to a conventional in-take manifold, the distributor pipe of theexpansion intake system is longer andhas a smaller diameter, while the individ-ual intake manifolds are shorter.

Existing intake manifolds, such as theresonance intake manifold, use the airvibrations in the intake system to fill thecylinders with as much fuel-air mixtureas possible. The compression effect(compression of air) achieved duringthe air vibrations is used for this pur-pose. The disadvantage of a resonanceintake manifold, especially in turbo en-gines, is that the air is heated up when itis compressed. This means that the fuel-air mixture in the combustion chambercannot be ignited with the best possibleefficiency.

For this reason, the current 911 Turbouses a resonance intake manifold that isdesigned so that, unlike naturally aspi-

rated engines, this effect only occurs inthe higher rpm range. This effect isneutralized at maximum power in thehighest rpm range. The expansion in-take system of the new 911 GT2 turnsthe resonance charge effect aroundcompletely at higher engine speeds: theprinciple of expansion (expansion of air)is used instead of compression.

During expansion, the air is cooledrather than heated as in compression.This effect results in a lower fuel-airmixture temperature in the combustionchamber, which means it can be ignitedin a more efficient manner. This im-proves engine efficiency and gives ahigher engine output with low fuel con-


6

The expansion intake system

For the first time, the Porsche expansion intake system has been installed in the GT2



7

Technical data

n 530 bhpn From zero to 100 km/h (63 mph)

in 3.7 secondsn Top speed 204mphn One-gallon (3.6-liter) six-

cylinder turbocharged engine

This effect may seem to be a disadvantage,but the raised temperature level meansthat more heat is discharged in the charge-air coolers, which in turn means that the airtemperature downstream of the charge-aircoolers is only slightly higher than with con-ventional charging.

This increase in thermal energy is accom-modated by using the expansion intakesystem which, through the expansion ofthe air in the subsequent intake system,causes noticeably lower temperatures of

sumption at high loads and enginespeeds. The name of the expansion in-take system is derived from the physicaleffect of expansion. The principle of theexpansion intake system can only be ap-plied in turbo engines. The cylinders arefilled with slightly less air during expan-sion than during compression. This ef-fect is compensated in the new 911 GT2by a slightly increased boost pressure.The increased boost pressure increasesthe temperature of the air downstreamof the compressor.

the fuel-air mixture in the cylinders at apractically equal air flow rate. As describedabove, these functional interactions, withthe help of more effective ignition, improveengine efficiency and give a higher engineoutput with low fuel consumption at highloads and engine speeds.

The environment has also been taken intoaccount. At maximum power output, fuelconsumption using this intake system isup to 15% lower than for turbochargingwith a conventional intake manifold.


In the spring of 1968, the FIA (FédérationInternationale de l’Automobile) imposeda new regulation for the World Champi-onship of Makes, which starting in 1969allowed both 0.8-gallon (3-liter) proto-type race cars and 1.3-gallon (5-liter)“production sports cars” (with the re-quirement to build at least 25 identicalvehicles) to participate in the long-dis-tance race. Porsche figured they hadgood chances of finally winning the world

championship title with a vehicle in the1.3-gallon production sports car catego-ry, as well as scoring the victory in theprestigious 24 Hours of Le Mans race. Inrecord time, the engineers developed anair-cooled, 12-cylinder naturally aspiratedengine, which impressively reached the setgoals. In 1969, 1970, and 1971, Porschewon the World Championship of Makes;in 1970 and 1971, the 917 vehicles tri-umphed with double wins in the 24 Hours

of Le Mans. But this dominance almostproved to be the brand’s undoing. For1972, FIA changed the rules again and1.3-gallon sports cars – and thus the 917– were no longer allowed to compete inthe Championship of Makes races. ButPorsche did not want to send the out-standing racecar to a museum just yet.The decision was made to compete in theCanAm series, which knew neither dis-placement nor weight limits. For Porscheto hold its own against the establishedCanAm competition, whose racecars wereequipped with large 1.8- to 2.1-gallon(seven- to eight-liter) V8 engines, thetwelve-cylinder engine of the 917 wouldhave to be turbocharged.

Pioneering work in development

Never before had turbocharged enginesbeen used in road races. The dynamiccharacteristics were so poor that the turboengines were not competitive, despite in-creased power output. But the engineerswere able to develop a new technology forcontrolling the boost pressure, thereby al-most completely eliminating the dreaded“turbo lag”. A valve in the exhaust pipe,which is controlled by the boost pressure,opens when the desired boost pressure isreached and, bypassing the turbine of theturbocharger, guides the exhaust gas thatis not needed to the outside. This new con-trol technology allowed significantly im-proved tuning of turbo engines, partly be-cause now smaller turbo units could be

Engine Engine of the 917

As the most powerful racecar in the world and with the “Greatest Sports Car in History”

award under its belt, the reputation of the Porsche 917 is legendary. This prestige is

largely thanks to the most powerful air-cooled engine of all time.

Bright prospects: the air-cooled, turbocharged Porsche 917/30 won hands down in 1973

8

1,100 bhp – the engine of the legendary Porsche 917


used. In addition, it resulted in a reductionof thermal engine loads.

Finally, the new technology paved theway for the triumph of turbocharging.Now it was no longer just motor sports –production car engines were also suc-cessfully turbocharged.

The most powerful automobileengine of all time

With 1,000 bhp under the hood of the1.3-gallon turbocharged engine, Porscheparticipated in its first CanAm season in1972, with the main intent of gaining ex-perience. But the Porsche 917 Turboimmediately won six of nine races, thussecuring the CanAm championship title.

The following season, 1973, Porscheshowed up with the most powerful auto-mobile engine of all time. The 1.4-gallon(5.4-liter) version of the twelve-cylindernow delivered 1,100 bhp at 7,800 rpm,and a maximum engine torque of 1,100Nm at 6,400 rpm. This guaranteedextravagant acceleration values (fromzero to 100 km/h – 63 mph – in a mere2.4 seconds). Porsche then went on towin the 1973 CanAm championship, witheight victories in eight races. After thisvictorious run, though, the rules werechanged again to the disadvantage of the917, so that Porsche had to retire fromCanAm racing. This ended factory-spon-sored racing of the 917 for good.

Outstanding performance is nothingwithout an engine that endures

The heart of the Porsche 917 is an air-cooled twelve-cylinder engine in 180-

Engine Engine of the 917

9

through axial feed on both ends of thecrankshaft. Thus the 12-cylinder engineowes its proverbial reliability andruggedness mostly to its center drivedesign.

A complete work of art in enginedevelopment

Almost 40 years after its first race, thePorsche 917 is now a legend. Thedevelopment experience of Porscheand the special construction providedimpressive proof that it was smart notto retire the 917 after such a short timein competing in the World Champion-ship of Makes.

degree V design with two overhead cam-shafts per cylinder bank. The centerdrive is the design highlight of this en-gine. In this design, the power take-offis through a set of gears in the centerrather than at the end of the crank-shaft; an intermediate shaft then trans-mits the power to the transmission. Thedrive gear in the center of the crank-shaft – where there is no torsionalvibration – also drives the camshaftsand all secondary power take-offs. Thisoffsets the torsional vibrations, makesthe engine more robust, thus consider-ably increasing its life. In addition, it en-sures the proper lubricating oil supplyfor the critical connecting rod bearings

Powerhouse: the twelve-cylinder engine achieves a stable 1,100 bhp at 7,800 rpm


The consistent use of state-of-the-arttechnology and methods can significant-ly shorten development times for newengines. The intake port geometry inthe cylinder head decisively affects theflow quality of the intake air in the cylin-der (see diagram, p. 10). Since the de-velopment of new combustion process-es, such as direct injection systems,called Direct Fuel Injection (DFI) at

Porsche, the development of the intakeports has become an even more de-manding task.

The right dosage is everything

Depending on the combustion process,intake port development pursues differ-ent sub-goals. Here, the large air flowrate that is often desired must be

weighed against the targeted tumble orswirl flow indication. In spark-ignition en-gines, especially in those with direct fuelinjection, the incoming air is swirledaround the lateral axis of the cylinder toimprove mixture formation. During thesubsequent compression and fuel injec-tion, this targeted air swirl achieves fastand direct homogenization of the fuel-air mixture. This optimized fuel burning

Engine Intake port development

Porsche Engineering masters the challenge of optimizing intake ports with flying colors.

This describes a method where a number of improvements are implemented during the

early stages of development.

10

It’s all in the right mix



11

the definition of a certain velocity of flowand the flow rate.

For intake port design, Porsche Engi-neering uses the CAD program CATIAV5, for which our own design methodhas been developed (see graphic, p. 11).In the CAD models, the designers rely ona highly parameterized geometry, whichthey control centrally through designspreadsheets in Microsoft Excel. Thesespreadsheets not only import parame-ters into a CAD model, but also exportmeasured data from cross-section curvesand represent them graphically. In pre-vious versions of CATIA, each cross-section had to be measured and entered“by hand” into a graph. As a whole, theparameters and measured data tell thedesign engineer whether the specifiedvelocity of flow was reached.

The faster control and evaluation of dif-ferent models in CATIA V5 is a definite

Design of an intake port using a CAD model thatwas created with CATIA V5

advantage in the designing of variants.A defined number of parameters allowsfaster and higher-quality design of in-take port variants, for example with adifferent cross-section curve. The use ofa CAD program makes the modelingprocess many times more efficient.

Parallel to the creation of the port mod-els in CAD, critical points, such as thewater cooling jacket or the valve springmounting, are examined for narrowing.In the past, this analysis was also doneby hand. Today, the experts at PorscheEngineering use the CATIA V5 DMU(Digital Mock-Up) Navigator for auto-mated narrowing studies, to examine allcritical areas more accurately, quickly,and reliably for compliance with the re-quired wall thicknesses and their opti-mization potential. The narrowing pointscan be shown in color in the complexcylinder head assembly, thus makingthem explicit.

process significantly reduces nitrogenoxide, particulate, and CO2 emissionswhile improving fuel economy. At thesame time, the flow rate can be im-proved by minimizing the flow resis-tance in the intake port. This in turn haspositive effects on the engine perfor-mance.

More powerful engines, buteco-friendly, please!

By optimizing the intake ports, PorscheEngineering not only achieves better en-gine output; with a targeted charge mo-tion in the direct injection processes,CO2 emissions are lowered at the sametime. The flow rate (called the alpha kvalue) is a general formulation whichtakes the losses occurring in the intakeport flow into consideration. These arecaused by friction and the inertia of airmasses. High engine power requires ahigh flow rate. Changing the cross-sec-tion of the intake port affects the veloci-ty of the flow, while the port geometrydetermines the direction of flow. Thefaster the air enters the cylinder, themore vigorous the swirl.

True, the development of intake ports isnot new. What is new, however, is thesimulation options Porsche Engineeringhas available thanks to computer-aidedcalculations. The geometric influenceparameters of intake ports are numer-ous, since any change in geometry af-fects the flow.

Intake port development today

Intake port development starts with thespecification of different goals, such as



12

Once a large number of intake port vari-ants has been generated in the designphase, the next step is to determine thebest variant for the combustion process.Even after the design phase PorscheEngineering relies on advanced, com-puter-aided analysis methods for deter-mining the flow properties of differentintake port variants. In the past, eachpart was built as an STL (stereolithogra-phy) part; that is, an accurate plastic(epoxy resin) prototype of an intakeport variant that was subsequently test-ed on a flow test stand to determinethe alpha-k value and the charge mo-tion it produces. Building these proto-types is very time-intensive. Today, apre-selection is made from all variants,and only the variant with the greatestpotential is tested on the flow teststand. The engineers at Porsche Engi-neering use a CFD (Computer Fluid Dy-namics) program that is fully integratedin CATIA V5, allowing more efficient cal-culations (no reformatting or data ex-

ports necessary) and objective evalua-tion within one day (see diagram, p. 12).

Unsuitable variants can be eliminatedbeforehand. The preferred variants,where the alpha-k value found in theCFD simulation proves promising, willthen be validated on the test stand us-ing stereolithography. With this step,Porsche Engineering can also save de-velopment time and costs.

Porsche Engineering sets a standardwith this new method for developing in-take ports. This achievement by the en-gineers not only saves resources, devel-opment time and costs, but also actuallyenhances quality and more clearly inter-meshes the processes. The develop-ment engineers at Porsche Engineeringsee future areas of application for cus-tomers in the layout and optimization ofexhaust manifolds, brake disc coolingand intake systems, as well as the flowcharacteristics of catalytic converters.

CFD simulation to evaluate air swirl, using the example of a port configuration for a diesel engine with direct fuel injection


Drivetrain Measuring methods

13

Making sure the engine and transmission are ready for action

More than ever before, the develop-ment process in the automotive sectoris characterized by increasingly shorterdevelopment cycles for a higher num-ber of vehicle variants. To reach the am-bitious goals of the automotive industryregarding CO2 reduction, coupled withrising demands on vehicle comfort anddynamics, the drivetrain needs to con-tinuously shed weight, despite increas-es in engine power. Of course, the relat-ed rise in weight-specific performanceof the vehicles must not compromise

component reliability, thereby increas-ing their failure risk.

The purpose of testing the componentseither on the test stand or in the vehicleas part of the development process isto show the failure risk of the vehicle incustomer use. A basic requirement ofrepresentative testing is that the testspecifications accurately describe whatthe components are to withstand lateron, taking into account the permissiblefailure rate in customer use. If the test

programs are too stringent, even slightdamage will not be permitted, resultingin reinforcement of components, whichmay lead to excess component weightand additional costs for measures toextend the life of the vehicle. Too littletesting bears the risk of weak spots go-ing unnoticed, resulting in componentdamage when the vehicle is used by thecustomer. The consequences can beunpleasant.

Besides the ultimate goal of testingwhat is important, this must also in-creasingly be done at minimal cost andtime expenditure. We have to test theright things (reasonable componentloads) in as little time as possible (hightime acceleration) and at minimum cost.

Through various measuring and testing methods, Porsche

Engineering makes sure that efficient layout and testing of

drivetrains is possible in the early stages of development.



14

lightweight commercial vehicles), trans-mission testing comprises statisticalvariables, such as the routes driven, theactual vehicle load, and the very differ-ent driving styles to which the vehiclemight be exposed in customer use. Theterm “customer” includes the tradition-al private person as a car buyer as wellas customer groups and commercialusers who operate vehicles under spe-cial conditions.

Vehicle measurement at PorscheEngineering

The objective of the vehicle measure-ments performed by Porsche Engineer-ing is to measure the characteristic op-erating loads on the drivetrain that areto be expected in day-to-day operationwith sufficient statistical certainty overdriving distances of up to 15,000 kilo-meters (9,321 miles) in a given timerange. The measuring conditions havebeen specified to consider all major in-fluential parameters, such as routecomposition, driving style, and vehicleload. In subsequent data preparation,load spectrums for precisely definedcustomer usage potentials are thenderived from the measurements. Themeasuring technology is designed tosurvive customary “day-to-day” opera-tion as well as extreme loads fromabusive maneuvers, such as so-called“idiot starts”, without damage.

To record measured data from a traveldistance of more than 15,000 kilome-ters over three weeks of vehicle opera-tion within the set time range, themeasuring system must be character-ized by a reliable system start, failure-

proof function, and memory capability.The system is started with a centralswitch that supplies all booster andmeasuring blocks through a centralpower supply. False measurements dueto system components that wereswitched on “accidentally” must beavoided. The same applies after con-clusion of the measurement: if individ-ual components are mistakenly notswitched off, the vehicle battery is dis-charged before the next round ofmeasurements. The signal scope of themeasurement series is usually up to150 signals, which are measured duringthe time range between 2,000 Hertz(torques) and one Hertz (temperatures).

Rugged and cost-saving newdevelopments

Special challenges for measuring oper-ating loads are posed by driving maneu-vers with extreme torque peaks, suchas highly dynamic friction value jumps,idiot starts, and traffic light starts. Sincetorque measurements are based on theelastic deformation of drive compo-nents, using conventional side shaftswith wire strain gauges applied (so-called measuring shafts) would notachieve the intended goal. After the firstabusive maneuver, such shafts areusually so deformed that they exceedthe measuring range of the shaft. In aneffort to circumvent this problem, PorscheEngineering, together with a systempartner, have developed innovativemeasuring flanges (see diagramm, p.13)that – while comparable with conventionalmeasuring shafts regarding precision andcosts – can withstand torque peaks of upto 8,000 Nm, undamaged.

Multi-level measuring system configuration in theluggage compartment of a sports car

Major goals in componenttesting:

n Reasonable component loadn High time accelerationn At minimal cost

To define the test specifications of adrivetrain component, its future world-wide area of application must thus bedetermined. In addition to the basic re-quirements of the technical specifica-tion, such as engine variants and vehi-cle segments (SUV, sedan, sports car,



15

Quantifying load spectrums

The measured data, which are aroundthree terabytes per vehicle and repre-sent around 240 hours of driving in thetime range, are used to quantify theloads on the drivetrain, the so-calledload spectrum. Its content is defined bymixed operation in cities, on interurbanroads, and freeways, dependent on driv-ing style and vehicle load.

In addition to the torque load, the loadspectrums also describe functional in-teractions or actions in the drivetrainthat are of special interest for compo-nent layout and testing. For example,how often does a hydraulic valve forvalve-lift adjustment switch over a dis-tance of 100,000 kilometers (62,140miles)? How often does the oxygensensor measure certain temperatureranges in onroad operation? What is thepower take-off of the secondary units ofthe engine (power-steering pump, air-

conditioning compressor, and alterna-tor) in real operation? How often do cer-tain gearshifts occur on a given roadsection? What are the resulting loads onthe gearwheel of the gear in question,and how significant is the influence ofdriving style on all these parameters?

On the left is an example of the diagramof a mid-sized car in mixed on-road op-eration comprising city, interurban, andfreeway driving. The right-hand area isdefined by the full-load characteristiccurve. The maximum engine outputrange is located in the front of the dia-gram.

Detailed analysis of testingdata sets

After measuring, the data sets areprocessed in raw data preparation. Dur-ing the subsequent detailed analysis,load spectrums for all major load pa-

Damage equivalent torque on the rear axle (all gear levels)

Gear levels 1 - 6

Damage equivalency curve1

Drive

torque

oftheax

letran

smission

Crown wheel contortions (log)

The diagram shows the load spectrum of a rear axle transmission with sub-spectrums from six drivinggears in traction and overrun.

Overrun

Traction

2

34

56

Engine dwell time diagram

Enginespeed [rpm]

0

rameters (including output, torque, andtemperatures) are analyzed. Theseanalyses are performed separately fordifferent customer types as far as theyare relevant to the vehicle layout, name-ly for a defined combination of roadtype, driving style, and vehicle load. Inorder to derive test programs, onemust either determine damage-equiva-lent test time/test torque data or sub-ject the data in the time range to vari-ous time acceleration methods. Afterthat, they can be represented on thetest stand in a time-accelerated simula-tion test.

This method shows that the subject ofload spectrum definition for the drive-train can be mastered systematicallywith the right special measuring tech-nology. The benefits that these dataprovide to development in defining thetechnical specification undoubtedly jus-tify the high expense.

Time [s]

Enginetorque [Nm]

Engine dwell time diagram for a mid-sized vehicle


Complete vehicle Cayenne S Transsyberia

16

Off-road dream: the Cayenne S Transsyberia

On the basis of the Cayenne S, Porsche has built a special

model for the most extreme outdoor situations. The

driver's safety is assured. Even on the most rugged terrain.

With its intelligent all-wheel drive, itspowerful and efficient V8 engine withdirect fuel injection and height-adjustableair suspension including Porsche ActiveSuspension Management (PASM), thePorsche Cayenne S is well equipped forany terrain. And to top its sportiness: acar based on the Cayenne S and tai-

forced, extra-large underbody paneling,as well as reinforced wishbones onthe front axle. Another highlight is thenew Porsche Dynamic Chassis Control(PDCC), whose two active stabilizers al-most completely offset lateral inclina-tion when negotiating curves. Even off-road the PDCC allows the maximumpossible wheel articulation, therebyincreasing the traction of the electroni-cally controlled all-wheel drive. TheCayenne S Transsyberia is Porsche inits purest form, tailored to the needs ofsporty and highly ambitious customers.

lored specifically to the requirements oflong-distance rally racing has been de-veloped in the Weissach DevelopmentCenter. Compared with its urban cousin,the “Cayenne S Transsyberia” featuresspecial off-road tires with rougher treadbars, a safety cage, a shorter final-driveratio, a rear-differential lock, and rein-



17

Rally properties with a proventrack record

The engine of the Porsche Cayenne STranssyberia was taken almost withoutmodification from the on-road versionof the Cayenne S. The 1.3-gallon (4.8-liter) V8 naturally aspirated engine withdirect fuel injection achieves 385 bhp(283 kW) at 6,200 revs per minute. Themaximum torque of 500 Nm is attainedat speeds as low as 3,500 rpm. Vario-Cam Plus valve management ensures asmooth and consistent surge of powerthroughout the entire speed range. De-pending on the engine speed, the elec-tronic engine management systemswitches the intake valve stroke from0.1 to 0.4 inches (3.6 to 10 millime-ters). The length of the intake manifoldcan also be varied, thus achieving ahigh torque curve at low rpm. A re-duced-weight sports exhaust system onthe Cayenne S Transsyberia produces aparticularly striking tone. Tiptronic-Stransmission, with shortened final driveratio and transmission control opti-mized for off-road use, provides in-creased acceleration power.

Offroad performance: for the things you have to do – and the things you just can’t leave alone

62% of the engine torque to the rearwheels and 38% to the front wheels.The distribution ratio can be varied inline with the current driving situationusing an electrically actuated and con-trolled multiple-disc clutch. But even100% of the engine power can betransmitted either to the front or therear as needed. The map-controlledcenter-differential lock and the rear-axle limited-slip differential do morethan simply respond to insufficienttraction at the rear or front axles. Sen-sors also measure the vehicle speed,the lateral acceleration, the steeringangle, and the accelerator pedal’s posi-tion. Thus the PTM is always able tocalculate the required degree of lockingfor both axles and properly split thedrive torque between them. A rear-dif-ferential lock has been installed in or-der to enhance off-road performance.

Off-road – yes, please!

One fundamental factor in the outstand-ing driving dynamics of the Cayenne STranssyberia is its power transmissionto all four wheels. In basic mode, thePorsche Traction Management (PTM)permanent all-wheel drive transmits



18

ble air filter snorkel, to ensure that the“bow waves” created when drivingthrough water cannot enter the intakeduct. Likewise, the wheels and suspen-sion of this ultimate sporting performerwere designed for extreme endurance.The double-arm front axle comes withreinforced wishbones and a track widththat is 1.3 inches (34 millimeters) wider.The standard high-speed tires havebeen replaced with rough-tread off-road tires.

On difficult terrain in particular, thePorsche Dynamic Chassis Control (PDCC)in conjunction with the air suspensionand the Porsche Active SuspensionManagement (PASM) increase traction.When driving in water, the maximumfording depth at High Level II of the airsuspension is approximately 30 inches(75 centimeters). In addition, the bodyand doors are sealed against water upto side window height. The air intake hasbeen moved to roof height using a flexi-

Maximum safety in a crash

When it comes to body rigidity and pas-sive safety, the Porsche Cayenne holds atop position among off-road vehicles.More than 60% of the body-in-white ismade of high-strength steel. A three-tierdeformation zone absorbs forces duringa collision and distributes them to therigid lower longitudinal members, doorsills, and tunnel area. The reinforcementsin the A- and B-pillars are manufacturedfrom high-strength steel to protectagainst roll-over. To protect both driverand passenger in competitive situationseven better against the consequences ofa collision or roll-over, the Cayenne STranssyberia has an additional safetycage, which is bolted to the passengercell and compliant with FIA design regu-lations.

The bare necessities

To offset the extra weight of the safetycage and rally equipment and to furtherlower the vehicle’s center of gravity, therear seats, standard interior body pan-els and soundproofing material have allbeen removed from the car. The centrallocking system has been replaced witha manual locking mechanism for thefront doors with orange loops. The rearwindow and the rear side windows aremade from lightweight polycarbonate.As in all Cayenne models, the front sidewindows have a hydrophobic coating.Water is repelled and runs off, whichmake the glass less prone to soilingthan conventional windows. Both thedriver and front passenger enjoy thebenefits of lightweight sports seats withAlcantara covers.

Solid safety cage in the interior


Equipped for any situation

City driving is not exactly a favorite ofthe Transsyberia. It is built for extremeoutdoor situations. To successfullymaster particularly difficult and de-

manding terrain, as well as to salvageother vehicles, the Cayenne S Transsy-beria comes with a winch that is easyto fit if necessary and is stored in theluggage compartment.

The luggage compartment also comeswith two 5.3-gallon (20-liter) reservecans, a hydraulic off-road car jack, twofire extinguishers, two sand panels,two full-sized spare wheels, and twotransport boxes for tools. Also onboard are two two-man tents, twosleeping mats, four tightening straps,a 29-foot (nine-meter) rescue belt witha chain joint, a folding spade, a foldingsaw, an axe, and a working headlamp,along with four towing lugs, and aHAZET tool set.


19

The ultimate sporting performerwith technical highlights

The Cayenne is equipped with a naviga-tion system as standard; it allows off-roadtrip planning and can be operated by thepassenger. The glove compartment hasbeen replaced with a Tripmaster comput-er, helping the copilot find routes betweenthe various navigation points. Most of thecontrol units are installed in the interiorand all electrics cables have been rerout-ed. The on-board electrics can be quicklyswitched on and off with a central switchon the lower right of the driver’s seat,making it possible to reset the electronicswhile driving.

Reinforced, extra-large underfloor panel-ing made of aluminum and an additionalcover made of stainless steel for the ex-haust tailpipes protect the Cayenne STranssyberia from damage caused by the

enormous stresses of a rally. The typicalfoot-operated brake on the Cayenne Shas been replaced with a handbrake,which can be used to oversteer the carin tight curves. Four auxiliary high-beamlights are mounted on the roof.

The Cayenne S Transsyberia always cuts a good figure

The large tailgate conceals complete rally equipment


Electronics as the key technology playan increasingly important role in the in-formation and communication age. Easeof operation, multi-functionality, high re-liability, and real-time responses are themajor requirements of contemporaryhardware. This trend applies increasing-ly to the automotive industry, as morecomplex and faster hardware finds itsway into modern cars.

The Hardware Lab basically followsthree trends: the linkage of multimediaand sound systems; the use of state-of-the-art electronics to reduce consump-tion; and finally, increasing passive and

active safety through intelligent integra-tion of assistance systems.

Diligent development process

In all hardware developments of PorscheEngineering, quality is at the top of thelist. For this reason, all developmentprocesses are aligned with the Porschestandards. Increasingly complex productscombined with shorter time-to-marketand more demanding quality expectationsmake it necessary to determine customerrequirements early on and to create arealistic test environment for the futureproduct. This is one of the specialty areas

of the Porsche developers. Often it takesthem only a few days to create an initialsample (A-sample) of complex controlunits that can be used in integrated sys-tems and that provide fast, real-timefeedback regarding the future feasibilityof the customer’s requirements. The ap-plications on the control units are firstmodeled, simulated, and then tested ex-tensively in executable code on the targethardware (Rapid Prototyping). This way,specification and development errors canbe discovered in a very early phase of aproject. If needed, we will support ourcustomers throughout further develop-ment with B-, C-, and D-samples, up to

Insights The Hardware Lab

20

Tailored solutions for demanding customers

Typical Porsche: the Hardware Lab of Porsche Engineering develops products that meet

the highest standards and customer requirements. Efficiency and intensive customer

support go hand in hand.


three months after the start of produc-tion. Veteran experts support the cus-tomer on the way to a successful prod-uct and help with all development steps,all the way up to approval testing andconsultation regarding electromagneticcompatibility (EMC).

Development examples – productportfolio

High-performance audio amplifiers andmusic player interfaces for vehicles areexamples of recent innovative develop-ments by the Hardware Lab. These proj-ects often involve easy-to-operate inter-faces between consumer electronics andthe audio system of a vehicle. Other proj-ects are in the areas of electric drives,electric drives for sports equipment, andinnovative solutions in combination withhybrid drives. Their extensive knowledgeof battery technologies, which increasinglycontributes to the success of future prod-

Insights The Hardware Lab

21

ucts, makes the Hardware Lab an attrac-tive partner. After all, the engineers in theHardware Lab have many years of expe-rience with the integration of vehicle assis-tance systems into complete vehicles.


Special 911

22

911 – a synonym for performance

When the new Porsche was presented atthe International Motor Show (IAA) inFrankfurt am Main in September 1963, itbore the identification plate “Type 901”.The development department had donediligent preparatory work to exclude pos-sible objections to the type designation,so they had every reason to feel safe. Atthe Motor Show, the new sports car re-ceived a great response and the successof the “Type 901” seemed predestined.

Imagine the development engineers’ sur-prise when an objection from a Frenchautomaker arrived at the end of 1964,

claiming that it – and it alone – had theexclusive right to use type designationswith a zero in the middle.

The new sports car from Porsche metwith a positive response all over theworld. Yet, after intensive internal legalinvestigation, renaming it was unavoid-able. Still, the elegance of the vehiclewas to be maintained for a new launch.After the Porsche had caused such afuror in such a short time with its 901number addition, just as the type 356had in its time, they were adamant aboutkeeping the nine and the one.

The obvious solution was to double theone: 911. This decision was made rela-tively fast. Without delay, the graphic de-signers at Porsche tackled the graphicimplementation of the change. And theirbrushstrokes demonstrated taste andconfident style. Over time and acrossmodel changes, the upright, angular 911logo morphed into the rounded, slightlyitalic lettering, the typical “Carrera logo”,as it is called internally.

This logo has long since become an op-tical distinguishing feature of this model.It is also legally protected – as a regis-tered trademark. The fact that thePorsche type 901 became the type 911only a year after its initial launch certainlyhas not harmed its career.

Historical deciphering of the Porsche success code

revealed surprising findings – about the “zero” hour

of the 911.


Complete Vehicle · Styling · Body & Safety · Engine · Drivetrain · Chassis · Electrics & Electronics · Testing · Industrial Engineering · Production Engineering

Power is work divided by time.

Plus passion.

For information about Porsche Customer Development visit the website or contact:

Phone +49 711 911-88888, Fax +49 711 911-88999

Internet: www.porsche-engineering.com, e-mail: [email protected]

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Publisher’s data

PublisherPorsche EngineeringGroup GmbH

AddressPorsche Engineering Group GmbHPorschestrasseD-71287 Weissach

Tel. +49 711 911 8 88 88Fax +49 711 911 8 89 99

Email:[email protected]:www.porsche-engineering.de

Editor-in-ChiefNicole Möller

Porsche Engineeringdriving identities

Porsche Engineering Magazine


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Porsche Engineering Magazine...because Porsche Engineering works wherethesetwoareasmeet. The joint knowledge of Porsche Engi-neering converges in Weissach – and yetitisgloballyavailable.Ofcourse,also