Porsche model overview

[st-anger]

Originally Posted by lakatu Originally Posted by st-anger i mean the viscous coupling is really a helpfull thing, and if one is quite skilled the AWD is nearly a perfect solution, of course weight remains an issue... So with a skilled driver like WR would the cornering speed be slower, the same or higher with a: 1. 996 Turbo compared to 2. 996 Turbo with the 4 wheel drive system removed and thereby weighing less?

hard to say again, the whole AWD system is ~50-60kg more weight, but i tend to say that the AWD car should be faster, BUT on the other hand, when we´re speaking of true performance, pro racers´d like to have a car that has a tendency to oversteer, and no understeering at all, so AWD even with the whole viscous coupling system isn´t an option mainly because of weight and it´ll understeer a bit when you through it into the corner hard, but as i said, we lift the throttle when entering to force some opp lock and the car´ll oversteer a bit, and then hit the accl again, sure, this takes time too, but you won´t be happy if you´re pushing it pedal to the metal into a corner...
it´s really hard to answer that question, on the one hand there´re quite some benefits but to tell which one is significantly faster....well i think we can´t really answer that question.... but nevertheless IMO it´s at least quite as good as the lighter RWD, probably slightely better, depends on the driver as well, driving a RWD Porsche, e.g. GT2, at the limit is quite challenging, with a e.g. TT X50 everything is much more smoother and you´ve a better feeling for the car...what´ll it do next and stuff like that...

[Toronto]

wow i loved the GT and GT2 write ups thanx for spreading your knowledge

[Toronto]

ps have you ever met walter rohrl when he was testing and help building the CGT?

[lakatu]

Originally Posted by st-anger pro racers´d like to have a car that has a tendency to oversteer, and no understeering at all

Thanks st-anger your comments are insightful. I have heard that experienced drivers prefer oversteer to understeer, why is that?

[st-anger]

Originally Posted by lakatu Originally Posted by st-anger pro racers´d like to have a car that has a tendency to oversteer, and no understeering at all Thanks st-anger your comments are insightful. I have heard that experienced drivers prefer oversteer to understeer, why is that?

first the answer to your question toronto, yes, i´ve met WR hundreds of times, he´s present at the EZW quite some times, and also at the NS during testing mainly at industry pool sessions, you know, he´s an official Porsche test driver, so, he work´s for PAG...
when you meet him and even work with him it´s beyond anything you could imagine, this guy is just supercool and extremely professional, he´s the most passionate Porsche employee i know...

so, why oversteering better that understeering....???
the one and only reason: a car with oversteering characteristics is simply faster, even when it´s quite tricky at the limit you´re still faster than with a car that has a understeering tendency.
as you know, understeering "happens" quite fast, you approach a corner at high speed and enter it hard, with a badly balanced car, the first thing what´ll happen is understeering and you´ll loose the line immediately, the car "runs wide", you´ll have to go off the accl, then stabilize the car, in the meantime you´re righ in front of the curbs and you even have to brake a bit not to end in the grass, at that time somewhere at the apex you´ll have to arrange the car again for the line with the better grip, again some time loss and you have to accelerate again, but the car has understeering so it run´s wide again at the exit and one can´t properly accelerate for the next straight...
so i think it´s obvious that it´s really bad to have understeering...
but as i said b4 there´re some tricks to force the car to oversteering...
and that´s the point, forcing a understeering car to oversteering, so oversteering must be the best way...
even with a badly balanced car you won´t have oversteering that fast like understeering, and when you finally have oversteering it´s very easy to stop it, just lift the accl a bit and the car has full grip again, of course, to say so you´ve to be a quite skilled driver. to understand better, just look at some F1 drivers, some of them want a car that oversteers a bit, you´re simply faster, it´s very controlable, when you know the car you also know when it´s enough, i´ve to say that i exactely know when e.g. a 996TT is at its limit, i can push it very very hard some spectators might think now he´ll loose it but it´s all under control...
so, understeering is and just costs a lot of time, oversteering can be corrected within seconds and allows you to significantly go faster...

[Fleischmann]

THX for the info St-Anger, thx for taking your time to shed us some light on the wonderful world of Porsche automobiles. And the pics uploaded to imagestation.com are fabulous!! The 911 Turbo is already on my desktop as I am writing this

[st-anger]

starting a short new topic:

:arrow: MY 2004 Technical Features



Ceramic Clutch and Brake Discs

PCCC and PCCB Available only from Porsche

Over two years ago Dr. Ing. h.c. F. Porsche AG became the first car maker in the world to develop the ceramic composite brake disc with involvent cooling ducts presented in the 911 GT2. And today, introducing the ceramic clutch in the Carrera GT, Porsche is again becoming the first car maker to unveil the second innovation using this trendsetting material, the Carrera GT indeed featuring both of these breakthrough components. Called the Porsche Ceramic Composite Brake (PCCB), this innovative brake technology is a huge step forward, setting entirely new standards in the world of motoring, particularly when it comes to crucial criteria such as brake response, resistance to fading, weight, and service life. The unique benefits of the PCCC Porsche Ceramic Composite Clutch, in turn, lie in the compact exterior diameter and the low weight of the clutch plates.

PCCB: weight down by 50 per cent

Like Porsche's conventional metal brake discs, the ceramic composite brake discs are crossdrilled and vented from inside. In their dimensions they also differ only slightly from greycast iron discs. But comparing their weight, you will see right away that we are looking at two different worlds, with ceramic brake discs more than 50 per cent lighter. This reduces the weight of the 911 GT2, for example, by approximately 18 kg or almost 40 lb. Apart from saving fuel, this also means a reduction in unsprung masses with a further improvement of suspension response and behaviour. On the road the new brake system ensures absolutely exemplary results. In conjunction with the all-new brake pads, the ceramic brake disc ensures very high and, in particular, consistent frictional values throughout the entire deceleration process. This spares the driver unpleasant surprises whenever having to apply the brakes, say, from a high speed. Brakes which initially appear to offer good grip but are not designed especially for high speeds like the brakes on a Porsche, lose their frictional coefficient in hot temperatures, requiring the driver to press down the brake pedal even harder. Porsche's trendsetting brake system also offers obvious advantages in emergencies at low speeds: In such a case emergency application of the brakes with PCCB technology does not require substantial pedal forces or any technical assistance serving to build up maximum brake forces within fractions of a second. Instead, the Porsche Ceramic Composite Brake ensures maximum deceleration from the start without requiring any particular pressure on the brake pedal. And PCCB brakes are just as superior in their response under wet conditions, since the new brake pads, in conjunction with the cross-drilled brake discs, help to optimise brake response and behaviour also in wet weather. Ceramic brake discs do not have the slightest problem with high loads occurring particularly under sporting, dynamic driving conditions. Compared with metal brake discs, surface abrasion is very low indeed thanks to the extremely hard surface of the ceramic discs. Working life, in turn, is increased accordingly. A further factor contributing to this very long working life is the total avoidance of corrosion: The ceramic brake discs are absolutely immune to salt scattered or sprayed on to the roads, for example by automatic spraying systems on motorway bridges.

Another world-first achievement: the ceramic clutch

The Carrera GT is the first car in the world fitted with the PCCC Porsche Ceramic Composite Clutch. A special feature of this world-first achievement is the compact exterior diameter of the clutch plates, allowing Porsche’s engineers to give the entire drive unit a very low centre of gravity. Another decisive factor is the low mass weight of the clutch, with a positive effect on the engine’s dynamic performance. So far only a carbon-fibre clutch has been able to meet these requirements, but with a much shorter service life not meeting the requirements imposed in this case in terms of everyday use. Exceeding the service life of even conventional clutch plates, the PCCC clutch is an all-new design and structure, Porsche’s engineers using their excellent experience with PCCB ceramic brakes and at the same time developing the qualities of this special material to an even higher standard for use as a double-plate dry clutch. The principal fortes of this material are its enormous hardness, low weight and, in particular, its outstanding service life. The two ceramic clutch discs made up basically of carbon-fibre and silicon carbide measure just 169 millimetres or 6.6 inches in their outer diameter, versus an exterior diameter of 380 millimetres or 15.0 inches in the case of a conventional clutch.


more to follow....

[lakatu]

Originally Posted by st-anger even with a badly balanced car you won´t have oversteering that fast like understeering, and when you finally have oversteering it´s very easy to stop it, just lift the accl a bit and the car has full grip again, of course, to say so you´ve to be a quite skilled driver.

Thanks again st-anger or should we say Professor st-anger with all the schooling we get.
Your answer raises a question I have been puzzled over for some time. I've read when entering a corner if the rear end begins to lose grip and oversteer, you should apply power to transfer weight to the rear and regain traction as opposed to lifting off the gas. This comment is usually associated with rear weight biased 911's. However, I have also read comments that suggest the same thing that you indicated in your post which is that if you back of the gas the rear end will hook up again.

I have never understood the first suggestion because it seems to me if the rear tires are sliding and have begun to lose traction, applying more power should further reduce the traction and increase the oversteer and not result in a transfer of weight to the rear tires. Whereas lifting off the gas it seems should slow the rotating tires allowing them extra grip and thereby decreasing oversteer.

I'm sure the conflicting advice pertains to different oversteer situations or the cars weight distribution. Do you know the answer?

[st-anger]

Originally Posted by lakatu Originally Posted by st-anger even with a badly balanced car you won´t have oversteering that fast like understeering, and when you finally have oversteering it´s very easy to stop it, just lift the accl a bit and the car has full grip again, of course, to say so you´ve to be a quite skilled driver. Thanks again st-anger or should we say Professor st-anger with all the schooling we get. Your answer raises a question I have been puzzled over for some time. I've read when entering a corner if the rear end begins to lose grip and oversteer, you should apply power to transfer weight to the rear and regain traction as opposed to lifting off the gas. This comment is usually associated with rear weight biased 911's. However, I have also read comments that suggest the same thing that you indicated in your post which is that if you back of the gas the rear end will hook up again. I have never understood the first suggestion because it seems to me if the rear tires are sliding and have begun to lose traction, applying more power should further reduce the traction and increase the oversteer and not result in a transfer of weight to the rear tires. Whereas lifting off the gas it seems should slow the rotating tires allowing them extra grip and thereby decreasing oversteer. I'm sure the conflicting advice pertains to different oversteer situations or the cars weight distribution. Do you know the answer?

lol, no thank´s, i´ve enough of the whole title thing, every day at work, every time you answer the phone, i can´t hear it any more
i´ve a first and last name and that´s it...no "doctor", no "Dipl.Ing.FH" and definitely no "Professor"...

well, the first statement is IMO completely nonsense, i´ve never heared of anything like that in such a combination, i think i could say i´ve tons of race track practice and i can say you´ll definitely loose it when you´re at the limit or slightly beyond, already drifting and you should floor it...??? hopefully there´s enough space, otherwise it´ll get expensive...
second comment is better, but not precise enough, completely lifting the accl isn´t that advisable, one´d completely lift it when you want to force the car to oversteering, like we discussed b4, but e.g. with a RWD car, you´ll lift the accl only so much it´s necessary to prevent a spin, a bit oversteering isn´t that bad, so you mustn´t "wait" until the car is completely balanced... it´s hard to describe you´d have to feel it yourself to completely understand, but the main point is, that you should only slightly lift the accl, definitely not completely because you´ll get into serious trouble because of load-cycle change, so keep it under load, but definitely don´t floor it, that´d end up in serious problems...
well, hope this helps again, i think you understand the main points

[lakatu]

Originally Posted by st-anger Originally Posted by lakatu Originally Posted by st-anger even with a badly balanced car you won´t have oversteering that fast like understeering, and when you finally have oversteering it´s very easy to stop it, just lift the accl a bit and the car has full grip again, of course, to say so you´ve to be a quite skilled driver. Thanks again st-anger or should we say Professor st-anger with all the schooling we get. Your answer raises a question I have been puzzled over for some time. I've read when entering a corner if the rear end begins to lose grip and oversteer, you should apply power to transfer weight to the rear and regain traction as opposed to lifting off the gas. This comment is usually associated with rear weight biased 911's. However, I have also read comments that suggest the same thing that you indicated in your post which is that if you back of the gas the rear end will hook up again. I have never understood the first suggestion because it seems to me if the rear tires are sliding and have begun to lose traction, applying more power should further reduce the traction and increase the oversteer and not result in a transfer of weight to the rear tires. Whereas lifting off the gas it seems should slow the rotating tires allowing them extra grip and thereby decreasing oversteer. I'm sure the conflicting advice pertains to different oversteer situations or the cars weight distribution. Do you know the answer? lol, no thank´s, i´ve enough of the whole title thing, every day at work, every time you answer the phone, i can´t hear it any more i´ve a first and last name and that´s it...no "doctor", no "Dipl.Ing.FH" and definitely no "Professor"... well, the first statement is IMO completely nonsense, i´ve never heared of anything like that in such a combination, i think i could say i´ve tons of race track practice and i can say you´ll definitely loose it when you´re at the limit or slightly beyond, already drifting and you should floor it...??? hopefully there´s enough space, otherwise it´ll get expensive... second comment is better, but not precise enough, completely lifting the accl isn´t that advisable, one´d completely lift it when you want to force the car to oversteering, like we discussed b4, but e.g. with a RWD car, you´ll lift the accl only so much it´s necessary to prevent a spin, a bit oversteering isn´t that bad, so you mustn´t "wait" until the car is completely balanced... it´s hard to describe you´d have to feel it yourself to completely understand, but the main point is, that you should only slightly lift the accl, definitely not completely because you´ll get into serious trouble because of load-cycle change, so keep it under load, but definitely don´t floor it, that´d end up in serious problems... well, hope this helps again, i think you understand the main points

Thanks, someday I'll feel it myself but until then your explanation creates a vivid image. I hope within the next couple years to get a 911 3.2L. Have you ever driven one?

Everything that I've read about them indicates that they are tricky handlers at best and at worst unruly beasts unable to be exploited to anything other than 85% of their capability.

I do have some hope for them though. I have read that in the 80’s Porsche had product liability suits over the 911’s handling that caused Porsche to limit the handling by introducing loads of understeer to prevent high cornering speeds.

I’m hoping that handling characteristics can be improved by lowering the car, corner balancing and wider tires and rims.

Does anyone have experience driving a 3.2L or know where I can get information as to how to improve their handling and what’s their ultimate handling potential?

[st-anger]

VarioCam Plus

Two Engine Concepts in One

Porsche offers VarioCam Plus on all models throughout the range. Camshaft adjustment on the intake side (VarioCam) is supplemented in this case by valve lift control also on the intake side (Plus). Featured for the first time on the 911 Turbo, this soophisticated system is able to optimise output and performance, on the one hand, while at the same time reducing fuel consumption and exhaust emissions, and improving running smoothness and refinement, on the other. The valve adjustment system is made up of switching cup tappets on the intake side of the engine operated by an electrohydraulic 3/2-way switching valve. With two different cam contours on the intake camshaft, the engine always runs on the appropriate lift curve, with the cams switching from one to the other. To be specific, the cup tappets are made up of two interacting tappet elements locked one against the other with the help of a bolt. This creates a direct link, first, between the inner tappet and the small cam, and, second, between the outer tappet and the large cam. A hydraulic compensation unit for valve play is integrated in all cases in the tappet’s force flow line.

Variable valve lift

For all practical purposes VarioCam Plus means two engine concepts in one. As long as the engine is idling, valve lift is controlled by the small cams to a maximum limit of 3.6 millimetres and valve timing is optimised to keep any valve overlap on the engine to a minimum. The small valve lift serves to reduce friction, significantly increases the charge motion thanks to the very short opening times, and reduces emissions from any previous combustion within the combustion chambers. A further advantage is the considerable reduction in fuel consumption and emissions by up to 10 per cent, together with a much higher standard of idling quality. Under part load, in turn, the engine should preferably run with internal recirculation of exhaust gases in order to minimise any throttle effect and to reduce fuel consumption accordingly. To achieve this goal, valve lift is shifted to a large overlap area, that is a long period for drawing in exhaust gases. Under full load, finally, superior torque and output are ensured by a highly efficient gas charge cycle with minimum losses, on the one hand, and an uncompromising cam contour, on the other, with 11 millimetres maximum valve lift and suitably adjusted opening and closing times during the valve cycle. VarioCam Plus also helps before you set out, for example, by considerably improving the engine’s starting characteristics when cool and by reducing emissions through the suitable adjustment of VarioCam Plus while the engine is warming up Both of the two VarioCam Plus systems (camshaft adjustment and valve lift control) are masterminded by Motronic ME7.8 designed especially for these particular requirements and offering a high standard of operating and computing capacity. This is indeed important, since the factors required for controlling VarioCam Plus are, in particular, engine speed, gas pedal position, engine oil and coolant temperature, as well as recognition of the gear currently in mesh. The driver’s commands in terms of engine power or torque are compared with controlmaps within the system, the Motronic control unit then deciding within milliseconds how VarioCam Plus should respond.

[st-anger]

Tiptronic S with Five and Six Gears

Sporting Comfort Porsche-Style

In addition to five-speed Tiptronic S on the 911 and Boxster, Porsche offers six-speed Tiptronic transmission in the Cayenne. This is a brand-new development tailored specifically to the high torque and power level of the Cayenne Turbo. Featuring appropriately modified shift units and a special torque converter, the new Tiptronic transmission is also ideal, of course, for the two other Cayennes. Apart from the additional gear allowing even more precise and individual gear increments, the option to shift gears manually simply by briefly touching the selector lever fitted in addition to the existing paddles on the steering wheel ensures maximum flexibility. All the driver has to do is press his thumb forward slightly to shift up and pull it back to shift down. The particular advantage of this enhanced control option is the safer gearshift in rough terrain. To avoid possible gearshift errors when driving offroad, the paddles on the steering wheel are deactivated when the offroad reduction gearbox is in mesh. In that case the driver can only shift gears by moving the shift lever, Tiptronic using gearshift control maps to ensure optimum dosage of power on rough terrain. A further feature of Tiptronic S in the Cayenne is the hill-holder function preventing the car from rolling back when setting off in a forward gear even on a 100 per cent gradient.

Manual short-term transmission in the automatic mode

A major feature of Tiptronic S is the option to briefly intervene in the transmission while in the automatic mode. This means that the driver, moving a toggle switch on the steering wheel, can shift gears manually even though the selector lever remains in automatic. The manual mode is thus activated for at least 8 seconds, this minimum period being extended when the car is in overrun – for example on a downhill gradient – in order to capitalise on the braking effect of the engine, or under lateral acceleration in bends whenever the driver shifts down in advance for a particularly sporting style of motoring. As long as this mode is active, the letter “M� comes on in the right-hand instrument dial and the gear currently in mesh is displayed. At the same time the transmission retains its kickdown function enabling the driver to shift down spontaneously whenever required: Road and engine speed allowing, the automatic transmission will shift down by a maximum of three gears as soon as the driver steps hard and quickly on to the gas pedal.

What counts is your foot on the gas pedal

In the automatic mode Tiptronic S offers various programs with different control maps readily available in the control unit and activated automatically as an infinite function of the driver's style of motoring on the route he is taking. The range of shift points extends from a particularly economic variant activated whenever the driver prefers a calmer and more reserved style of motoring (with the gears shifting up at an earlier point and engine speeds being reduced accordingly) all the way to a very dynamic, active mode (with the gears remaining in mesh for as long as possible when accelerating, using the engine's free-revving driving characteristics). The crucial factor in all cases is the driver's foot on the accelerator: Moving the gas pedal quickly and dynamically, for example on a winding road, and accelerating frequently with full power, the gearshift points will change accordingly, switching if necessary to the most dynamic variant and vice versa. Over and above its ability to recognise the driver's style of motoring, Porsche Tiptronic S also features the following particular highlights:

• Warm-up program preventing the transmission from shifting up at an early point in order to increase the temperature of the catalytic converter as quickly as possible, at the same time allowing the engine to warm up smoothly and without any strain

• Active gearshift immediately moving the shift points to the most sporting and dynamic gearshift program whenever the driver presses the gas pedal quickly and dynamically

• Suppression of upward gearshift in overrun when the driver suddenly takes his foot off the accelerator, for example before entering a bend

• Downward gearshift to the next lower gear when applying the brakes, in the interest of an optimum engine braking effect

• Increment upshift from the lower gears, the transmission not shifting immediately to the highest gear in particular after an active downward shift

• Hill recognition retaining the lower gears as long as possible in uphill or downhill gradients

• Retention of gears in a bend in order to prevent any upward shift

[SPEEDKILLAR]

All that technology, I bet alot of ppl who own such cars, aren't even aware of it

Thanks for the info.

[SPEEDKILLAR]

Isn't vario cam originally from bmw or ferrari, can't remeber it?

[st-anger]

Originally Posted by SPEEDKILLAR Isn't vario cam originally from bmw or ferrari, can't remeber it?

i´m afraid no, the system you´re talking about is VANOS from BMW...
"Vario Cam" is a Porsche invention...