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Glenn 911

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Posts posted by Glenn 911

  1. For the sake of closure and thanks for the advice I wanted to follow up, I intended to return the wheels to 18" but couldn't find what we wanted in a timely manner, a decent looking black 5 spoke. We were looking at the Victor Baden's but couldn't find a full set in 18" or 19" so we opted for staying with 19" rims and chose the Bridgestone Potenza S04 pole position 235/35 19Y tires up front and 305/30 19Y's in the back on Roderick 19" x 11" RW5 's in matte black (about as tight of a fit with this wheel as one could get without spacers). After a month on the car I have to say we are really pleased with the setup, the previous configuration was pretty bone jarring this is the perfect combination of looks, comfort, handling, road noise and performance. Wet weather handling exceeded my expectations.

    Thanks again for everyone's input !

  2. If the tire sizes are exactly equal, there is no shear at the VC coupling, hence minimal drag, or lock up.  If there is a front to rear bias in outer diameter of the tire, then the VC silicone fluid is shearing - and causing some low % of lock up.  Smaller rear diameter causes transfer of power to the front.  smaller front diameter causes drag on the engine at steady cruise speed.  Disclaimer, I was an engineer at a major silicone fluid manufacturer in Germany for 13 years of my career...

    I've never known an engineer to be so cavalier about precision, In the spirit of the forum it would have been helpful if you'd just answered the question .....

  3. If the tire sizes are exactly equal, there is no shear at the VC coupling, hence minimal drag, or lock up.  If there is a front to rear bias in outer diameter of the tire, then the VC silicone fluid is shearing - and causing some low % of lock up.  Smaller rear diameter causes transfer of power to the front.  smaller front diameter causes drag on the engine at steady cruise speed.  Disclaimer, I was an engineer at a major silicone fluid manufacturer in Germany for 13 years of my career...

     

    Hi guys thanks for all of the posts, my manual lists the summer tire sizes as 225/40 ZR 18 front and 295/30 ZR 18 rear, I found this website that was helpful   https://tiresize.com/calculator%C2'> (click on the tire size calculator for rev/mile info) /, Dave is your comment related to the difference in revolutions per mile ? From that web site the difference 804.3 rev/mile front to 808.2 rev/mile rear is that the impact that you are referencing for fluid shear ?  Is that the impact in % difference that xmaciek82x is referencing ?   Should I try to keep those front to back numbers as close to together as possible to eliminate the shear ? And as close to Porsche specs to keep the speedometer and odometer reading correctly ?

     

    xmaciek82x does that combination throw off the speedometer, based on that website the rev/mile is listed at 783.6 front & 777 rear ?

     

    Thanks

     

    Glenn

  4. What is your priority? Looks or performance? If looks, just try to find a tire size with similar outside dimensions to the stock tires. The rim size doesnt matter its the O.D. Of the tire that is important. The 19" wheel will use a shorter sidewall tire compared to the 18" wheel, but the o.d. Needs to be close to the same.

    If Performance is your goal, ditch the 19" wheels and go back to the 18". Thats what the car was designed for. 19" will work but because of the shorter sidewall the suspension characteristics will change a bit and the car will tend to tramline. There is no advantage to larger wheels unless you need larger brakes. In GT racing the only time they run 19" wheels is if the track is fast and they need to run more brake.

    But if you just want the look of the 19" just keep the o.d.s close to stock.

    Thanks for your response,

     

    Buying the car second hand, I don't know all the mods that have been done to the car as far a larger brakes etc, I'm satisfied with the overall performance and don't plan on racing.  So based on your note, I am correct that the 235/40 19" up front and 295/30 19" rear will work,  correct ? The 19" rim size is only referring to the rim size the tire will fit, I don't have to buy lower profile tires to compensate for larger rims. I just want to be certain before I put an order in for these tires.

     

    Thanks

    Glenn

  5. Hi,

     

    I have a 2004 996 TT.  I purchased the car with 19" rims on it and I'm not sure what to do about replacement tires.  The front tires that came on it are Michelin 235/35 ZR 19, the rear tires are Azenus 275/30/ ZR 19.

    With the difference between the stock recommended and the mismatch on the tires now, I'm not sure if any thought was given to the correct sizing.  I have to replace the fronts, the rears are new.  I'm

    more inclined to replace all four. Does anyone have any insight as to what the best size selection would be for this ?  It's a summer car that only sees rain when the unexpected shower shows up if we

    are out on the road. Does consideration have to be given to the 19" rim for height, i.e. do I have to keep a lower profile tire due to the 19" rim vs an 18" or 17" rim ?

    I would like to go a little wider even if I had to put some spacers on as I'd like to enhance the look of the wide hips of the car. Would 235/40 19" up front and 295/30 19" rear work and accomplish this ?

    Any thoughts would be appreciated !

     

    Thanks

     

    Glenn

  6. Yes there are two hydraulic Rams that are fed from the pump housed in the rear lid under the fan housing. The pump like any hydraulic system pumps the fluid through the bottom of the ram, to extend the piston and the top or reversing flow to retract it.

    Have you nticed any fluid leaking usually residing in the caps on the bottom of the rams. I would check to see if the Pistons are raising

    Uniformly, same speed same pace, any binding also when the pistons are extended are there any scratches or gunk on them that would impede free movement

    My system was almost bone dry with residue in the caps on the bottom of the rams, I pulled the system out added fluid and bench tested it, it works great except for the occasional warning light. I took the car to work the other day and got no warnings at all, Im still pretty certain I Need to tweak/replace the top switch though

  7. Does it function properly otherwise ? I.e. Go up on its own when you hit the proper speed and retract when you slow down?

    Raise and lower when you press the button? If that's the case it's likely that it's one of the micro switches found on the passenger side ram under the snap on plastic cover. My spoiler wouldn't function at all. The fluid was leaking and really low, i removed it and purged and refilled the fluids but I bunged up the top micro switch and now I get a warning when it raises at speed I just haven't had the time to replace it. They are very small a very easily bent so be careful if you are investigating. My spoiler functions fine otherwise,but the warning is a bit of a nuisance. My alarm triggers when it raises, if your triggers when it retracts it's probably the lower one. There are two one at the top side of the ram and one at the bottom.

  8. Sorry to revive this old thread but it explains the situation that I'm having with my '04 996 TT and it's going in the shop on Monday and I have been told the same story. My independent wrench feels that it is repairable even though Porsche stated there was no gasket for that part. Has anyone else had any updates on this issue ? Has a new gasket hit the market or is a fabricated gasket a solution to this.

    Any input would be appreciated !

    Thanks

    Glenn

  9. I think Dharm55 read your title literally "radio". You have PCM which is a NAV unit with the radio built in. Use this procedure to remove it. attachicon.gifpcm1.png

     

    Hi,

     

    I'm trying to remove my PCM 2 unit and have found posts that reference the hex wrench and detents that need to be pivoted and then I saw this diagram

    that Loren posted a while back.  I have pivoted the detents, actually pivoted them right out of the radio so I know they are not providing resistance.  This

    is the first time that I have seen reference to a spring clip that needs to be pressed and it seems more in line with what I am experiencing.  I have a 996 TT,

    am I at the stage now where I just need to squeeze the tabs (that I do see) and pull the unit out ?  Pressing in the tabs and pulling seems to exert force on the

    remainder of the surround,the top vents and cup holders etc ?  Maybe I'm not pushing in hard enough ?  I saw a post that discussed removal of the vents ?

    I saw other posts referencing those european radio removal tools/keys but I don't see any place that they could be inserted, defiantely no pales to insert from

    the front. 

     

    Any Thoughts would be appreciated !

     

    Thanks

    Glenn

  10. Hi ,  I have a PCM 2.0  is there a separate code for the radio and one for the nav ?  It's my understanding that with this radio I have to go to the dealer to get this code retrieved. When I bought the car  they had put in a new battery so I'm wondering if they only had the code for the radio as it works fine but the nav can't locate any satellites.

     

    Thanks

     

    Glenn

  11. Do you have the two battery option?  It sounds like one of them might be dead.  The car will start fine because the second battery is protected from full discharging, but it sounds like your house load battery is failing.  Having an incorrect time can mess with the gps because the gps signals are timed coded, so I think the nav system is a symptom of some other problem.

    Hi, sorry for the late response, I just saw this. I didn't know there was a two battery option ?  Would it be located near the main in the front compartment ?

  12. Thanks for your interest, We've only had the car for a month.  I worked through the typical issues that seem to happen with these cars first.

    Spoiler, fogged lights. AC,  etc, now focusing on the NAV.  The nav doesn't report current location, recognizes the nav disk, and has a previous owners

    destination address list intact so it worked at some point.  My assumption was that since it registers no satellites it precluded it from functioning

    Some people report the antenna located in the area of the pollen filter others under the security dome I haven't really dug into searching for the

    antenna yet.  A casual search around the pollen filter came up with nothing, may have to dig deeper removing the trim pieces around the wipers.

  13. Thanks Spence I did, I get a reset on 1-4-8 but no resolution to the issue.  One odd thing of note, I set the clock at 12:50 today, I was doing some other things on the car

    I checked back and the time went to 12:49 ....  scratched my head over that one, then the next time I looked at it was 12:56.  I shut the car off and restarted the clock flashed

    to 8:43 then went to 12:50 and stayed there ....  odd ...the stem adjust in the dash will affect the time setting in PCM, but neither will allow the clock to run, nor the date to set which I

    believe is a function of the NAV.  I have heard two opinions that the sat nav antenna comes loose and one location is passenger side next to the wipers and the other was in the security

    led housing I'm trying to pinpoint the location of the antenna as it apparently comes loose.  I'm planning on digging into this tomorrow.

  14. Hi,

     

    I'm having the same problem with my '04 996 TT.  I have a PCM 2.0 and have not had any success with this problem.  I'm thinking it may be an issue with the GPS antenna ?  That is where

    I plan on looking next as it reads that it has registered 0 satellites. I'm Hoping that since the date is not settable that it acquires the date from the GPS system.  Hope to

    hear that you got your issue resolved. 

  15. Problem Solved !

     

    What I learned along the way :

     

    With the cd changer out of the loop the MOST bus was interrupted.  I was getting a tv, cd changer amp fault.  I built a Digital audio loopback connector and was able

    able to restore audio.  Still getting the TV and cd changer fault.  I was testing the input leads and could not detect power coming to the cd changer.  I found a blown

    fuse in the E row 6 or 7 I believe a 7.5 amp fuse.  I replaced the fuse and connected the new changer power and MOST bus, started the car and everything worked. 

    I didn't have to get a recode on the swapped out cd changer it worked fine. 

    I still get the TV fault, I have no idea what that is indicating based on what I've learned and from everyone's input possibly a backup camera was coded into the system.

    I'm having issues with the NAV not finding satellites and Clocks not setting , which I've had since we bought the car but those issues are for another day.

     

    It's amazing how much fixing the radio cleared up the "static" generated when the passenger seat is occupied ....... ;)

     

    Thanks to JFP in PA, Loren and wross996TT for your assistance !

  16. Thanks for the responses guys I really appreciate the information !

     

    I'm still concerned that the replacement unit was DOA as I don't believe the PCM would cut power

    to this device and I am unable to feel/see/hear any indication of life when I hit the eject button.

     

    I'll have to verify that with an external power system test before I make the trip to the dealer.

     

    Thanks Again !

  17.  

    We have a 2004 996 TT.  Our CDC 4 changer died.  We started getting TV,  CD changer, AMP, errors on the PCM 2 headunit. Of course the MOST loop

    is not completed so we have no audio.  We purchased a replacment CDC 4 and assumed that when we installed the unit all would be restored.  The

    new unit appears to be dead on arrival. I'm hoping that's not the case, but afraid it may be. My questions are :

     

    There are three cables in the power connector  that attaches to the CDC 4, I believe I saw somewhere that ground is through the chassis which of the

    three cables provides power, I'd like to connect the suspect DOA unit to an external power source to see if it's functional. (note : I verified the CDC 4 internal glass fuse

    was intact)

     

    Is there a fuse on the back of the PCM 2 that could have blown.

     

    I do not have the Radio code for the PCM 2 if I remove the Radio is the only way to recover a PCM 2 code via the dealer ?

     

    Would a MOST fibre loopback restore audio to the car ?

     

    Any help would be appreciated !

     

    Thanks

     

    Welcome to RennTech :welcome:

     

    Unless mistaken, I think you need to have the system recoded (PIWIS) when you change this unit out.

     

    Thanks for the Welcome and the response, are you saying I may need a recode to have the new CDC4 unit accepted or

    that if I eliminate the CDC4 and do a loopback that I may need a recode ?

  18. We have a 2004 996 TT.  Our CDC 4 changer died.  We started getting TV,  CD changer, AMP, errors on the PCM 2 headunit. Of course the MOST loop

    is not completed so we have no audio.  We purchased a replacment CDC 4 and assumed that when we installed the unit all would be restored.  The

    new unit appears to be dead on arrival. I'm hoping that's not the case, but afraid it may be. My questions are :

     

    There are three cables in the power connector  that attaches to the CDC 4, I believe I saw somewhere that ground is through the chassis which of the

    three cables provides power, I'd like to connect the suspect DOA unit to an external power source to see if it's functional. (note : I verified the CDC 4 internal glass fuse

    was intact)

     

    Is there a fuse on the back of the PCM 2 that could have blown.

     

    I do not have the Radio code for the PCM 2 if I remove the Radio is the only way to recover a PCM 2 code via the dealer ?

     

    Would a MOST fibre loopback restore audio to the car ?

     

    Any help would be appreciated !

     

    Thanks

     

     

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