tomnash

Porsche literature seems to suggest that the dynamic cornering lights option only moves the low beam. Is this correct? Driving my 2007 C4Cab tonight on a narrow twisty dark road, I was really wanting the bright line to swivel. If in fact the new option only applies to the low beam, why was this done?

If you can establish "a reasonable doubt" that you were not in the school speed zone when radar-measured, you should not be found guilty of violating the school zone limit. How fast you might have slowed down before actually entering the zone should not be the issue. However, I would not count on a traffic court applying the law appropriately.

I hope so -- as the whole point is you are downshifting and trying to match engine speeds. But it's engaged once inbetween, if you're double-clutching. Double clutching is more than I am capable of... and I don't think necessary with a modern Porsche gearbox.

I hope so -- as the whole point is you are downshifting and trying to match engine speeds.

I don't get this. A heel and toe works just fine -- first press the brake with the left side of the foot then roll right side of foot onto throttle. According to this thread as I read it, the throttle blip should not work. What am I missing?

I am very curious whether anyone knows if there is over-rev protection for downshifts with the PDK transmission in the new Porsches. Specifically, what will the PDK do if you manually request a downshift that would result in a mechanical over-rev? Does it ignore the request? and flash a dashboard warning? hold the request until the RPMs are low enough (I hope not)? or go ahead and execute the downshift and over-rev the engine? If if ignores the request, this would be a huge selling point for PDK, and it does appear to me to be technically fairly straight forward so I am guessing Porsche would have done it.

Seems like the aerodynamics of my Carrera likes to carry little rocks right into the windshield... There are 2 or 3 little craters and 1 with a 1/2 cm crack coming out of it. I bought a Permatex Windshield Repair kit and think I ought to fix the crack so it doesn't grow. Does anyone have any advice for me on doing this? Do these kits work? Any special issue with Porsche windshields? Better to have a specialist place do it? The damage with the crack is right at the bottom center of the windshield, an inch above the blacked strip. Thanks.

You don't say where you live ... Summer tires are dangerous in snow. Having said that, the question is how cold does it get where you will be driving? Below about 35 degrees F the soft rubber in summer tires has significantly reduced traction. This is not like snow, which is just plain dangerous on summer tires, with some care you can get away with driving occasionally at around or a bit below freezing on summer tires. If you don't do much snow but have frequent sub freezing driving days, go for the all weathers. For what it's worth, I live in the San Francisco Bay area and stick with summers all year around. I got very worried when I needed to drive back from LA through the Grapevine on I5 just after it had been opened after some winter storms. Although it was cold and there was some snow left on the side of the road, the road was clear and the driving was just fine on the summer tires.

~18 is typical except on interstates where I can exceed 20-22. Watch your rear tires carefully at around 10,000 miles or less. Check the *inside* wear as the camber is set up for racing and my tires, at least, wore unevenly after dominantly cross-country driving. Unless you have the car up on a lift it is hard to see the inside treads -- so reach your hand in and feel the treads!

It would be very difficult to get a speedometer/odometer based on wheel rotations to be as precise as you want -- tire circumference variability and tire slip cause too much uncertainty. And the manufacturers build in a bias addressing some maybe legal liability concern. However, what you want and what would give us real precision would be to use the GPS built into the navi system to optionally provide speed and mileage information. The usually quoted error on GPS speed (see Garmin site) is a tenth of a MPH. That would translate into road mileage errors of a tenth of a per cent at 100 MPH. Straight line distances from stop to stop could be measured with precision at the less than a meter level easily. Why this option is not available, at least on the Navi status display, never mind on the dashboard readout, is beyond me.

It was (and is) checked and I still see no evidence of any traffic info and I live in the middle of traffic jams. Haven't tried to change stations, but that shouldn't be the issue...

As I noted in an earlier post, there is no indication of any option or configuration screen that I can find for traffic information.

Navteq provides the data. I don't believe Navteq did this software. I suspect it is unique to Porsche, though perhaps based on a third party common framework used by other car companies. Porsche probably contracted it out, probably in Germany, where little roads don't run for hundreds of miles with only a few other roads around. The issue is how the "anti-clutter" parameters are set and whether these can be manually adjusted by the user. The anti-clutter algorithms keep the screen from getting filled up with too many little streets. For example, if you looked at San Francisco on a 4 mile scale and every little street showed, the screen would be black. However, streets encoded at the same level of significance (or whatever they call it) when you are down on the coast below Big Sur, or out in the desert, or in the Central Valley, or ..., are very interesting to a Porsche driver and should be shown. It is possible to write algorithms that simply count the total length of streets on a screen and on that basis dynamically adjust which ones are shown. This seems to be too sophisticated for most mapping routines I have seen (except maybe Google and MapQuest which seem to handle this more sensibly and automagically). However, even if you can't have this level of automatic anti-clutter adjustment, at least there could be a manual adjustment available under the Map/Set menu. For example, it could be called "Show More Streets" and you could adjust it by spinning the knob, just like you adjust the magnification. Or one of the useless (in the US) buttons could be reprogrammed, or ... Tom

I received the Nav upgrade from Sunset this afternoon. As I noted in an earlier post in this thread, my 2007 997 C4Cab is already at PCM software level C. So... I did not need to use any of the three upgrade disks and only needed to swap out the map disk in the trunk. Did that. After a few moments of reading the disk the system came up with what looks like the old maps possibly with some features I don't remember (like a dotted line at the Pacific Ocean indicating the boundary of the USA on the San Francisco beach??) and are presumably updated with new road and POI info. No problems with the install. Don't quite know why this has to cost over $300 given that the upgrade disks are not necessary... Trying out the system in my garage (in San Francisco), I see no evidence that Real-time traffic is supported, in these parts anyway. I took a look at the roads showing down around Big Sur. Coastal Route 1 still will not show up at any scale larger than 1.5 miles and many other interesting roads don't show at any scale larger than 0.3 miles. I had a small hope, now gone, that the upgrade might fix this glaring problem. It sure makes it hard to use the Navi system on many great roads in the west where one wants to see what is going on (intersections, etc.) further than 5 miles down the road! Does anyone have any idea who one might contact at Porsche of USA who might be interested in hearing about this issue? It is the only deficiency that really bugs me about this otherwise phenomenal car. Tom I should add that a map included with the new disk indicates that it now includes Mexico and Brazil, should anyone be planning to drive a Porsche down through Central America and Columbia into the Amazon regions...

I just read the navi update TSB (after contributing to RennTech...) and then checked the software release in my 2007 C4Cab. My car was at software Model Level C (and I am sure yours must have been also since it is also a 2007. According to the TSB, at this model level, all that is necessary is to swap out the maps DVD in the trunk. No navi software upgrade is required. I can't see that any Porsche dealer equipment would be required, despite the warning in the TSB that this upgrade should be done by a dealer. Can anyone tell me if I am making a wrong assumption on this. I am a pretty savy computer geek and this looks trivial, but I don't want to blow it... On the question of Traffic updates in the US, I don't see anything in the TSB that would indicate that this release would make that more enabled than before. The TSB indicates that upgrading to Model Level B (pre 2006), never mind Model Level C, would enable the traffic layer, if it is available. My reading is that this is just not available over the air in a format that the Porsche navi system can cope with in the US -- and the latest upgrade will not change that situation. I am hot to do this upgrade in the long shot hope that the new maps disk will fix an egregious problem with Porsche navigation now in the US, where many Porsche class roads are not displayed at scales larger than 3 mi and in some cases not at scales larger than 0.3 miles! A glaring example is Pacific coastal route US 1 past Big Sur, a Porsche road if there ever was one. This means you can't see towns or possible turns more than about 15 miles down the road (or 1.5 miles for some lovely even smaller roads). There are numerous other examples here in California and out in the deserts and plains. I think the parameters are set for European roads and there is no way to adjust them that I can see. I am not optimistic that the new disk will fix this, but I want to give it a try before hollering at Porsche on the subject.

On page 8 of the Christophorous magazine that just came out is a full page ad from Porsche showing a color picture of a German regional map on the PCM. Below are the words "Guiding you every step of the way. The navigation update from Porsche Tequipment." In little letters it says to call a German phone number for info or check the porsche.com site. Does anyone know more about this? Is there an update coming? I sure hope so and that it fixes some nasty things like the inability to see some great Porsche back roads on anything bigger than a 3 mi scale, in some cases only on even smaller scales. A classic example of this problem is CA route 25 south of Hollister...

The odometer bias is favorable to the car owner in a warranty dispute -- if the odometer says 50,001, you probably are at least 1000 miles over that. That avoids arguments and could be a key reason manufacturers do this. What I wonder is why Porsche does not display the GPS velocity on the status page of the navigation system. I am sure this is available in the software and is just not being displayed for some legal reason (?). It would also be easy to give the driver the option of displaying the GPS determined velocity on the dashboard instead of the wheel rotation based velocity. That would be really nice. It would also be nice to have a record of your GPS velocity over the last few minutes stored in the navi module in case of a traffic stop, but that probably never would be in my favor ...

A red line limiter and a velocity governor are different things. The BMW limits velocity probably because of safety considerations (lawyers?), maybe because even Z rated tires are not speced at higher speeds. Possibly that's a US only legal issue for BMW. I am pretty sure that the Carrera red line is the same in cars sold in Germany as in the US. It is meant to protect the engine from blowing up, not to limit your speed. The 6th gear limit corresponds to about 178 MPH (depending on model) and I doubt the cars have the horsepower to push air at much higher speeds. The power required goes as the cube of the velocity to move through the air. It takes 15% more HP (around 50 HP more) to push the car at 178 than at 170 MPH! (See http://en.wikipedia.org/wiki/Drag_(physics)) So you would need lots of time on a very flat, windless, road to have a prayer of getting close to the red line in 6th gear.

Was the mechanic at Family Porsche in Bakersfield? That's where I got towed to and they told me almost exactly what you said. I was looking to get some independent confirmation of this from my RennTech post. It's a plausible explanation, but it is puzzling that a factory set up car would wear so unevenly in the first 10-12,000 miles. If so, all new Porsche owners should get the same warning you got! Tom

Now they are set where the dealer set them on the new tires, 37 front/ 43 rear, essentially at the Porsche recommended full load setting: 36 front/44 rear. Usually I have them at the partial load recommended setting as I noted in the original post, which is 33/39. I use the numbers on the dashboard display of TPS readings that indicate temperature corrected differences from nominal, displayed only when car is stopped, and these agree within reading accuracy when the tires are at ~ 20°C with a manual digital gauge I got from TireRack a few years ago. I do not use the absolute numbers displayed when the car is moving.

Sorry ... They were the original Michelin Pilot Sport PS2 N3 on 18" wheels (295/35ZR18(99Y)). I replaced with the same. The dealer pulled in the camber to -1°18' and -1°22' when doing the realignment. I could feel a small difference on corners but much of that could have been because of the new tires.

I've owned a number of sports cars over many years, but nothing as great to drive as my 2007 997 C4Cab (manual, PASM), which I picked up last May and now has 11,700 miles on it. Based on experience with soft high performance tires on an S2000 (which were gone at 10,000 miles), I have been watching the tire wear carefully. But it never dawned on me that a factory aligned car would wear the the rears very unevenly. And I never checked the inside edges of the tires, which requires getting down on the floor and shining a flashlight on them. So ... over 100 miles each from four (!) Porsche dealers on a beautiful Porsche back road north of Paso Robles, out of cell phone range, I heard a bang and stopped before the tire flat warning turned on. Turned out that the inside edges of both rears had worn down to the steel belt, though the outsides were well above the tire wear indicator and looked like they had a few more thousand miles easily. Could the factory set alignment have gotten badly out of spec? No. Four days later, with the new tires on, alignment showed the rears to be within range, but with camber close to the negative max. The camber was at -1°42' left and -1°41' right, with the spec range for these cars with PASM -1°45' to -1°15' . The fronts did have the toe angle out of range (identically -10' and -11' for a spec range of 0' to +5'), but there was no sign of uneven front tire wear. A single tire hitting a pot hole would not have done this or pushed both the rears the same amount from where they had been set. So either it was some kind of common bump I hit (don't remember any), or the weight of the car changed the factory setup, or this is the way the factory set it. I would be interested in expert opinion on what happened here. I had all the tires at within 0-1 lb of specified pressure for half load when I was driving alone with little cargo, and full load spec when driving cross country with my wife and luggage. I would guess about 7500 mile was on cross country straight roads or interstates at 80 MPH or more, and the rest on winding Northern California coastal mountain roads. Does the factory routinely set up cars at maximum camber? Should one expect a new car to wear so unevenly in this kind of mix of driving? Was some of the cause of this keeping the tires at the half load pressure? Does alignment settle in significantly in the first 10,000 miles? Should I fuss at Porsche, even though the warranty explicitly excludes alignment issues? Should Porsche call this possibility out more clearly (along with the gazillion other warnings about tires in their manuals)? Any other suggestions or comments welcome (except snide remarks that I should have checked the inside wear).

I think this is correct -- for dry roads, the tire will heat up enough to be safe for occasional use as you describe. I started this thread and perhaps wasn't clear enough. If I were going up to Tahoe every weekend I would certainly get all weathers (and maybe even the $700 chains!). I asked the question because I may need to drive up to eastern Washington state for a week or so, a desert area with little or no snow, and 30-ish temperatures. On the way, one may go through some passes which are usually not snowy or icy. Similarly, I may want to head out to Utah, across Nevada, avoiding any snowy roads (taking the southern route if necessary). So I really was asking about cold but dry roads -- and only very incidental and occasional travel on them. It hardly seemed spending $4000 or so for this was warranted. Tire Rack will provide a full set of recommended all weathers on the low end wheels, mounted, for $3700, BUT they do not have the tire pressure sensors for 997s -- so even that option doesn't work. The Porsche manual is rather vague on this. Just a Maintenance Note "We recommend fitting winter tires on the vehicle at temperatures below 45°F (7°C)". I think this is meant to apply to places where you will be continuously driving at real winter temperatures. And the Michelin website says nothing about low temperature use on these tires. This is strange since they have all kinds of warnings about tire pressures and even tables of recommended minimum pressures at various maximum speeds. I sent Michelin a question about this last week, which has been acknowledged, but not answered yet - probably delayed because of Thanksgiving. I will post any answer I get. And, oh yes, I used to live in Illinois with a Honda S-2000. Driving on snow wasn't a problem, because I couldn't even get the car out of my flat driveway if there was anything white visible on it. So, I suspected that the summer 997 tires would be like this -- and I appreciate the confirmation from messages on this thread. I will certainly avoid snow! Tom

You might try to pull the fuses on the circuits for both the PCM and the amp. Then reinstall the fuses. This would be an attempt to force the PCM processors, etc., to reset themselves. Actually, I stole this reply from a suggestion by Peter Smith today on the PCA.org Technical Q&A in response to a 997 owner with an unresponsive radio. If this doesn't work, you might post a question to Peter -- he has lots of experience with bizarre behavior of PCM and related systems. I am also very skeptical that you should have to replace the amp. Tom

I live in the SF Bay region with a 2007 C4Cab and still with the factory Michelins. I understand that Porsche advises winter tires for driving below freezing even on snow cleared roads. Since I rarely get into these conditions, I am not thrilled about spending several K$ on a set of wheels and tires just to get across the Sierra or drive across Nevada in winter for a week or two. And less thrilled about putting tires on that won't perform well in normal driving here in paradise. I understand that the soft summer tires will harden up at winter temperatures. What are the exact issues with using them? Safety at normal freeway speeds (say under 100 mph)? Extra wear? Damage to the tires? Extreme bad handling? Or are they usable with some care on dry roads? What about a little snow (1 inch say)? etc.? Thanks for any input. Tom