sanjeev

Loren Thanks. This is great info. I wasn't aware that Porsche rotors could be machined, but it makes sense that as long as there is enough residual thickness above the minimum, then it should be OK. Makes it easier to replace pads and freshen the rotor surface to allow for a proper bed-in of the contact surfaces. Thanks, - Sanjeev

Hello, Wanted to check how far worn my front and rear brakes are. Car is a 2012 991 Carrera S. Does anyone have the specs for the minimum front and rear rotor thicknesses? Thanks, - Sanjeev

Thanks all. This is good info. Sounds like there are no issues once we stick to factory wheels (offsets). - sanjeev

Hi, Has anyone used 305 wide rear tires on the narrow body C2 cars without fitment or rubbing issues? I am looking to get a second set of wheels/tires, and find quite a variation in the aftermarket wheel specs. If so, could you share what tires/wheel combination works? I am especially interested in the wheel width and offset(s) used. Also, please state if any wheel spacers were used. Thanks Sanjeev

Yes, I agree that this adaptation logic is involved. I have confirmed that during driving (on open roads, with more ability to tip into the throttle) the PDK adapts its shift points to higher rpms. It is actually uncannily good at this! However, in city/slow-traffic driving, where one is invariably limited by the car right in front of you(!), I do think the shift logic adapts to shift points that are overly low. I suspect this is a trade-off made in the interest of eke-ing out as much fuel economy as possible. For someone who has driven for years with a habit of trying to keep the revs under driving load conditions above 1400~1500rpms, though, it is still a bit uncomfortable. I plan to drive an "S" to see how the Sport mode works under these conditions. If it avoids the "lugging" preference, I may install it anyway. If anyone has an "S" PDK, would you mind taking note of how the shifts occur under light throttle in Sport mode, and post your observations? Thanks all, - Sanjeev

MWS, thanks for your note. Interesting that you note the same sympton on an S model. Is this with the transmission in Normal, or in Sport mode? Reason I ask is that I was considering upgrading to the Sport Mode (available as an add on) if this would make the transmission shift logic less prone to lugging (or alternatively, more eager to downshift). Yes, I have somewhat adopted the manual override via the shift switches procedure too. However, i still think this should be a simple logic fix for the automatic mode. Sanjeev

Hi, I have a 2009 C2 w/PDK (non-S, therefore no Sport mode switch), and have observed that the normal shift strategy is to shift up to higher gears quickly under light throttle (such as regular in-town, in-traffic driving). Often, under these conditions, the engine will try to continue driving all the way down to ~1000 rpm in 2 and 3, resulting in a momentary lugging feel and sound on throttle tip-in. Dealer has checked and updated PDK s/w - no fault codes, and otherwise the car checks out and drives as normal. In other words, according to Porsche programming, this is operating as designed. Question - Has anyone else experienced this behavior, and if so, is there anything to be concerned about? In my previous Porsches (all manuals), I generally kept the revs above ~1500 rpm, even in light-throttle use. clearly this logic could just as easily be programmed in to the current PDK ECU. Does this mean that by design, the modern Porsche engines are OK with being driven (lightly) all the way down to ~1000 rpm? Related Question - Does anyone else feel like there is an excessive amount of engine idle vibration transmitted into the body (and felt through the seats) when sitting at a standstill in D or M? Thanks for any info - I'm trying to determine if this is considered normal, or should I be talking to the dealer. - Sanjeev

Usually the wiring looms are integrated across various functions throughout the car, so I would not expect that you could pull any single speaker pair through. Sounds like your easiest path would be to access and do continuity tests across the existing (ends of) speaker wires, to identify them. It is likely that you could then splice in your new speakers' pigtails to these, once identified. Generally, I've found the modern german cars to use acceptable spkr wiring (twisted copper, 16 and 18-ga). If you are serious about end-to-end quality, I would suggest running new 14-gauge, high-strand-count (audiophile?) twisted-pair wire for the Front Doors, Subwoofer, Front dash locations (first), powering those from your outboard amplifier(s). If you want to reuse the HU internal amp, using it to drive the rear speakers over existing spkr wiring is OK (low-level fill) . Locations - other than the HU in the dash, look for the factory amplifier in the trunk just behind the spare on the "firewall". All the existing in-car speaker wiring shold terminate in one or the other of these locations. Hope this helps.

I was referring to the CDR23 pinout diagram I posted earlier (primarily). You can also review a pinout diagram for the trunk-mounted M680 BOSE amplifier (attached). However once you gain access to the pins from the plug-in harness adapter, it is simple enough to inspect and test each pair to identify the connected speakers. Hope this helps. Good Luck. - Sanjeev PS: After reading multiple audio-installation DIYs, I decided to ground the HU directly to the chassis (instead of using the GND wire in the factory CDR23 plug A). Better to avoid ground loop induced noise, I'm told. (Curiously, I didn't experience any significant or noticeable noise either way, YMMV.)

I used Pins A4, A5 and A8 to connect the HU. You can get a compatible ISO-DIN harness adapter from most car stereo stores (I used a BEST KIT BHA1784). Hope this helps - Sanjeev CDR23-connectors.pdf

Hi all, I am almost thru the replacement of a CDR23 / BOSE amplifier (2003 MOST bus) , and wanted to share some of my install notes. I have gained a lot of insight by reviewing previous posts, and hopefully, can add some more to the collective wisdom on this topic! Briefly, I was able to successfully interface a Nakamichi CD400 HU and ARC Audio Mini 4-ch amplifier to the factory wiring harness using an Autoleads PC2-95-4 connector. NO CUTTING/SPLICING of factory wiring was needed, which was a key consideration for me. Result - It works, and sounds noticeably better than stock (w/ the factory spkrs). However, the factory spkrs' deficiencies have now been highlighted, so me-thinks a decent set of Focals, Morels, Dynaudio or the like is the next order of business! Anyway, if anyone is interested in details, please see attached PDF. Note, this is NOT a full DIY tutorial - if you are not familiar w/car stereo installations, I would recommend letting a shop handle this. I purchased this amp from Rod Birch (Car Audio Innovations) and his advise and help was indispensible for me to get thru this project. Thanks, - Sanjeev Amp-HU-install.pdf PS: I would highly recommend Rod Birch - he is extremely knowledgeable about these cars and their ins/outs relative to stereo installs.

OK, here's my $0.02 FWIW I'm used to oil changed regularly at 5k intervals (Mobil 1, factory filters) on my cars (M3, 996 C2, Audi). However, given that all the factory recommendations at 10k or above these days on European cars, I've been doing some research to find out if this is overkill. (LN Engineering, Charles Navarro has some good info.) Last oil change, I ran 7500 miles (incl. ~10 hrs track use) on Mobil 1, then sent the used oil in to LN for Oil Analysis (My 2003 996 has ~59k). The results came back that the oil was fine, and the oil quality was still significantly ABOVE the recommended thresholds for almost all of the indicators, with no indication of any lubrication-related/wear-related engine issue. Now that I've established a baseline for this motor, I'll continue to track it further. Again, I'm not prescribing anything, but I suspect the factory recommendations at 10k intervals are probably OK. Hope this helps. - Sanjeev

Jason, My advice for summer (performance) tires in winter season temps (less than 40 deg or so) is DEFINITELY DON'T!!! Even in the DRY, summer tires won't grip well if the temp is at freezing or below. I once purchased an M3 in Jan, and had to drive around for a few days with the Michelin Pilots (Z-rated summer hi-perf). It was around freezing (sometimes below at night, so the roadways get cold), and driving around (EVEN IN THE DRY) was scary! The car would lose grip under mild throttle (in 3rd gear) tiptoeing around on-ramps. I think the answer to whether you need dedicated winter tires depends on several things: 1) where do you live (ie. how much snow do you see); 2) even if you don't PLAN to drive in the snow, what is the likelihood that you could get caught needing to drive home in snow/freezing rain/icy conditions. If any of the above are true, then you should seriously consider winter tires. having said that, if you live in mid-latitudes (milder winters), it is certainly reasonable to me to use all-seasons. All-seasons are a compromise (by design), so don't expect race-car grip during the summer (or any time), but they won't go away quite as dramatically as summer tires do below 40 deg. Hope this helps. - Sanjeev PS: I've used all-seasons quite happily on my M3 and 911 (996 C2, currently Mich Pilot A/S Plus)) for winter driving in the Boston-area for several years, without any real issues. I do try to avoid driving it during storms, but the roads are generally well-cleared within hrs of a storm around here, and I'm OK for the occasional light snow. IF I needed to depend on this car for any-time use including regular snow driving, however, I would definitely get winter tires.

Why? might I ask... Short of going to a full weld-in roll-cage, with pickups at the suspension points, I'm not sure there is any real benefit to the typical "strut brace" here. The 911 monocoque chassis is pretty stiff, and rear multi-link suspension practically eliminates the need for such an add-on - rear shocks do connect vertical loads to the chassis, but lateral stresses are handled by the subframe and upper links. The typical performance upgrade is to replace the (rubber bushing) stock toe and upper links with spherical links ("dog bones"). However, I believe this is really only suitable for track use - Porsche designed in the mechanical compliance to provide a stabilizing rear toe-steer effect under lateral loading, and provide some compliance for ride comfort. So buyer beware, if you choose to go this route! If you still want to, check out GMG Racing, etc. They have the shiny racecar spherical-jointed links that so many find sexy. - Sanjeev

Hi, I don't know about the antenna wire, but here's a connection diagram for the CDR23. Do you have the (Pep Boys') part number for the speaker connector adapter you used? Thanks, - Sanjeev cdr23_connectors_1_.pdf

Hi, Assuming your suspension is in good order (this, I would say, is your first line to check), then yes, I would agree that 17" wheels with more sidewall will provide a slightly better ride. But, as the other posts have noted, ultimate handling response and grip will be lower. That said, I replaced the original F+R struts, and run 17" wheels on the streets, and am very pleased with the ride quality. Night and day difference with the original suspension (at ~40k miles, probably not worn out, just worn). Switching to 17" from 18" wheels had a lesser magnitude effect on ride, but still quite noticeable. I prefer to run the 17" wheels for daily driving, and now only use the 18" for summer occassional weekend drives (rarely!).

Lennie, Thanks for your feedback. I'm curious as to why you selected (or were advised) on the Torque Biasing vs the traditional LSD. What are the noticeable or functional characteristics that differ between these two types. Have you noticed any additional noise? Other issues? Greater understeer at the track? Thanks for your help. - Sanjeev

Hi all: I would like to have an LSD unit installed in my 6-sp C2 w/PSM (MY2003). What are the best options - here's the one's I think are potential - factory unit (from 2004 Anniv 911) - Guard Transmissions LSD (what type and specs?) - Quaife ATB Has anyone had experience with any of these? Retrofit costs? Potential hiccups, incompatibility w/PSM? Thanks, - Sanjeev

I have been experiencing a similar situation (2003 C2 with CDR-23 & Bose), although it usually occurs during th colder months (here in Boston area) say, Dec thru Apr. On startup in the morning, the radio will hang in it's startup process (display reads "PORSCHE") and go no further. At this point, nothing electronic works (buttons, etc.), no sound. BUT, the eject button works (if a CD is in), and sometimes by jogging a CD in & out, it eventually MAY start playing, maybe, if the car starts getting warm. This problem has been attacked by two dealers. They have replaced the Bose amp, CDR-23 radio (twice), and eventually replaced the MOST optical cabling. Problem is still there intermittently, and I've resigned myself to the fact that 2003 was the first year for the MOST system, and it has design flaws! The last speculation is that some combination of temp/humidity may be hampering the optical system, which needs to check out during the system initialization, before anything starts to work. Ultimately, I'll replace the whole kit+kaboodle witha decent HU, amp and spkrs, but for now I prefer just to not think about it (and how much $$$ I'll need to lay out!)

Hi all: I just had a KW Variant 3 suspension installed on my car (2003 996 C2), and felt I could share some first impressions. I had originally planned to go with the ubiqitious bilsteins, but I waited for months for the PSS10's, eventually getting p***ed off at Bilstein America for refusing to sell the PSS10s as long as retailers still had old PSS9 stock on hand. So my second choice... First off, the KW kit construction appears to be of good quality - stainless steel construction, and all parts bolted up with no issues. I set the ride height to the upper end of KW's recommended range, which appears to closely match the factory Euro M030 ride heights, which IMHO, is a good thing, to retain in the factory's bumpsteer characteristics. Also, since this is a daily driver, I wanted the clearance for speed bumps, driveways, etc. Had the car aligned to factory settings and corner balanced. So far, it passes muster on those. Street driving - this is a very compliant setup! After driving around my area (Boston roads - pretty bad surfaces!), I set the bump and rebound settings to favor ride quality, and I would say the ride is significantly better than stock! Softer over road imperfections, yet the car retains the firmness and better control of the upgraded spring rates (~200 lbs Front, ~515 lbs Rear, I believe). Cornering is flatter, and responsiveness is improved, at the same time as yielding a plush ride comfort. Hard to describe, but it's definitely there. That floaty front-end feel is gone, and the car feels more as one piece, rather than mostly the rear with a floaty front along for the ride :) Track driving - so I bit the bug and took it for a 3-day run at NHIS (New Hampshire Int'l Speedway, a 1.75 mile road course (superposed on the nascar oval), with some pretty technical elements and two heavy braking zones. I focused on the car's feel across transitions (and there are a couple of nasty pavement transitions mid-turn, which in a 911, you want to have really good transitional control of the rear (heavy) end. I used Turns 3 and 10 to focus the tuning. With the stock suspension, the rear end would bounce practically all the way thru 10 after the mid-turn pavement transition, which feels almost dangerous at times. Starting out with KW's recommendation for F+R bump/rebound settings, I would say it felt good almost everywhere, but not quite in 3&10 - like a pretty solid, sporty setup, but still a forgiving road car feel. Almost spot-on for the selected spring rates (which are really too low for a track car). But, the car was very enjoyable to drive "out of the box", and I was happily keeping pace with most of the other advanced (Group 1) drivers. This is a very good starting point, and entirely adequate for most tracks with smooth surfaces everywhere (say, Mt Tremblant, or Calabogie). For NHIS, however, I increased both bump+rebound beyond KW's initial setting, and immediately tightened up the transitional response across the focus turns and pavement transitions. At this point, the car is waayyyy better than I am, and I am very pleased with the setup. Despite attacking a couple of curbs at speed (including on the outside, loaded wheels at the track-out prior to the front straight), the suspension never bottommed out, and always felt tight to the track ("groundhook" damping). At the end of the day, it was pretty easy to reset the bump/rebound settings and drive home at the "comfort" settings. Given my mix of daily driving, with occassional sporting drives, I believe the KWV3 is really well setup and suited for street driving (& ride comfort is stellar). For those of you hesitant to consider coilovers for fear of a bone-rattling ride, I would easily recommend this kit, for it's versatility to be both sporty and comfortable. If you are more focused and lean to a dedicated track car, I would recommend considering a higher-spec kit - it needs more spring rate to really shine there, but the dampers are excellent, and have a large range to work with. (KW's clubsport version, w/ ~900lbs and solid mounts w/ camber plates, or maybe Cross, JRZ, Moton, etc.) Hope this is useful. - Sanjeev

Hi all, Ride quality is indeed a subjective term, but I believe the original poster may be referring to the relative harshness or smoothness of the car in running over typical less-than-perfect street surfaces under normal daily driving conditions. Many of the posters have commented on spring rates alone - I'd like to add that damper design, quality and characteristics have an even greater positive impact on BOTH ride quality (as defined above) and handling characteristics. This is why folks that have upgraded to high quality, matched spring/dampers (typically quality coilovers) find that ride quality & handling are simultaneously improved, EVEN with higher spring rates! Within reason, higher spring rates can also improve ride quality by helping to better control body/wheel motions, assuming that the dampers have enough rate to control the sprung/unsprung weight (especially bigger wheel/tires fitments) and higher suspension natural frequency. I personally have upgraded suspensions to more than double the original spring rates, and had comments on how smooth & comfortable the ride was. The damper curves, especially high-speed compression rates, have a significant effect on impact harshness. High-quality dampers (Moton, JRZ, Ohlins, etc.) do this so well, that frequently they can control triple+ the original spring rates, while still improving ride quality. From the Panorama article on factory 996 spring and damper characteristics, I believe the stock dampers are not the best for impact absorption (high-speed damping curve and/or blow-off characteristic?). For the 2003 C2 with USA stock suspension, I personally feel there is inadequate low-speed rebound control also, especially at the front (witness the light, floaty feeling as speeds approach or exceed 85mph). 996's respond well to a suspension upgrade. Even mid-priced units (PSS9/10s, KWs) should yield a better ride, with improved handling as well. Historically, twin-tube designs (KW, Koni, JRZ RS) have a more compliant ride quality than monotube designs (Bilstein, JIC, Porsche 996 stock rears), but this is also heavily influenced by other factors (valving design, matched springs/damper tuning, amount of lowering, etc.) No flames, please. I'm not commenting on the racetrack handling capability of either design - Monotube designs are likely indeed better suited to racing applications. Wheels and tires make a significant difference as well. For my taste, the 18" 225/285 wheel options are NOT well-matched to the USA stock 996 C2 suspension, even with 5-spoke wheels. It definitely feels undersprung/underdamped to me. Back-to-back drives in a similar 996 with M030 suspension revealed significantly better wheel control (less residual osscillations after bumps) with the 18" option, which equates to better ride quality IMHO - go figure. The stock 996 (02+) 17" ten-spokes (the ones pictured on the owners manual) feel better matched to the USA base suspension, and are a high-quality, relatively light assembly, but very few 996s were ordered this way, and used ones are hard to find (took me a while to do so). Aftermarket forged rims would be nice also, to lower unsprung weight even more. 996s with their massive (285+) rear tires, and relatively low sound-proofing transmit a lot of tire/road noise into the cabin. With proper tires in the 17" 255 sizing, it should help with ride compliance and minimizing tire noise (perhaps use high-perf sport-touring tires, rather than all-out max-performance tires). I've found Yoko Advan S4s to be a relatively quiet, comfortable tire for all-around daily driving (I use ten-spoke 17s). Hope this helps. - Sanjeev Previous to my 2004 C4S Cabriolet, I had a 2000 C4 Coupe with standard 17" Rims. The Cabriolet feels much more compliant and "softer" over bumps even with the 18" wheels. Maybe its me, but it certainly feels like the cabriolet spring rates are more flexible and lead to a smoother ride. I would check out cabriolet spring rates.

I have an 03 C2 with PSM as a daily driver, including winter. So far, it's been pretty good - however not quite as good as my previous car (a 97 M3). The main difference is that even with PSM, it's still an open diff, which is slightly less effective at getting you traction in the really slippery stuff. I'm considering installing an LSD soon, although I need to do some research first. Also, the ground clearance is not that great, so stay out of the deep snow (similar concern for any low-clearance car). As long as you drive carefully, you should be fine (winter tires go a long way!). - Sanjeev