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wwest

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About wwest

  • Rank
    Member
  • Birthday 07/31/1940

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Profile Information

  • Gender
    Male
  • Interests
    All things electronic, especially automotive electronic.

Profile Fields

  • From
    Redmond WA
  • Porsche Club
    PCA (Porsche Club of America)
  • Present cars
    1978 911 SC Targa, Seafoam/metalic Green, BBS-RS.
    1988 911 Carrera, SE (Special Edition)
    2001 996 C4, Wimbledon Green, Natural Brown Leather, BBS
  • Future cars
    Porsche Cayman with Toyota Prius HSD and SuperCharged.

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  1. If the lock solenoid does not fully extend then the controller will immediately unlock. Common problem, fix the solenoid or purchase a replacement.
  2. "Legacy" non-barrier A/C hoses DO NOT leak absent extreme high side pressures.
  3. No such thing as refrigerant leaks (strickly) due to "non-barrier" hoses....... My '92 R/awd Ford Arrestor, front + rear A/C, was just in the shop being converted to R134a refrigerant. Normal charge has been ~$160, this time ~$200.00. Difference was due to having to replace leaking o-rings on the rear of the Sanden compressor, something having to do with the refrigerant OVER-pressure relief valve. Say WHAT..?? According to the Ford factory manual if the refrigerant pressure rises to high then the valve opens to atmosphere to bleed off refrigerant, but then "resets", closes, to preserve the system integrity. But with the A/C compressor clutch controlled by a binary pressure switch why would the system ever go over-pressure? The answer would be an inadvertently overheated engine, cooling system, radiator, heating up the nearby A/C condensor and thereby raising the internal liquid refrigerant pressure. While I am by no means stating this as a definite answer for the reason our air-cooled Porsche's consistently lose refrigerant, it most certainly has a ring of truth to it. Drive our Porsche's HARD on a HOT day, making full use of the A/C, and now shut down the engine. How high would the pressure go in the rear lid condensor, overall high side, with all that engine heat rising up through the rear lid condensor. From what I could find on the INTERNET most automotive A/C compressors included an over-pressure relief valve, at least up until venting R12 to atmosphere was outlawed. Could this be the real, actual reason, our refrigerant charge only last 2 years? The stage is certainly correctly set.
  4. PSM is not simply stability control, it also includes traction control and "virtual" LSD functionality. Trac detects rear wheelspin/slip and INSTANTLY dethrottles the engine and will moderately apply brakes, ABS like brake modulation, if the condition persists. Winter tires often have a higher level of siping thus have less CSA for roadbed contact, additionally you mention they are narrower tires. All that adds up, for me, that Trac is activating.
  5. Why bother? What do you expect to gain? In any case the VC mostly remains flaccid, non-functional, due to Trac activation/intervention so you wouldn't be accomplishing much.
  6. Like most everyone else each spring I have to "top off" the refrigerant, now R134, in my '88 Carrera. A/C specialists have checked over for leaks many times in the past 16 years of ownership, and most recently when it was converted to R134 about 2 years ago. First, my theory, and then an explanation. When the car is parked with the engine and EXHAUST still HOT, convection airflow will HEAT the rear lid mounted condenser, likely very seriously so. How high might the resulting refrigerant pressure reach on a really hot, BRIGHT, day thrown in..? My pressure was at 65PSI this evening simply setting in a nice cool, ~55F, garage. Suppose, at the instant the ignition is switched off, part of the condenser, and all of the line to the recvr/dryer, and the dryer itself are FULL of liquid refrigerant, just as should be the case. The evaporator blower has also just been switched off reducing the heat exchanging capability of the evaporator significantly...AND...no compressor VACUUM. The high side pressure, LIQUID pressure, will now leak down VERY slowly. Might the high side pressure in that circumstance, BOILING whatever liquid might remain in the rear lid condenser, get high enough to begin leaking around the o-ring couplings...?? System leaks slightly, pressure subsides, until the next time. Anyone ever taken system pressure measurements in a situation as above. I'm thinking of revising my engine lid condenser fan system so it runs at half power with the engine switched off but with the high pressure compressor disable pressure switch open. Note: There is a REASON why my '01 C4 has an engine compartment cooling fan.
  7. The flasher relay in your 996 is already electronic. It uses a nichrome link to sense the current flow to the bulbs. If the current flow is low, indicating bulb failure, it goes into fast flash mode. Open up the relay and replace the sensing link with a 1 ohm resistor of 2 watts.
  8. Your priorities are seriously MISPLACED. Buy the best pads for BRAKING and spend the extra time cleaning the wheels.
  9. You should be aware that this is an extremely typical SCAM... You may be replacing two perfectly good parts. What tire shop..? Oh, your lifetime alignment package probably doesn't apply since you will be "intentionally" mis-aligning the car.
  10. No. The compressor shuts off if: The high side refrigerant pressure becomes too high or too low. WOT. The engine coolant "threatens" to rise too high. The cabin atmosphere reaches or is below the setpoint. OAT is below ~35F Evaporator surface temperature, close downstream airflow, is below 33F for more than 2 minutes.
  11. If you want more than 5-10% of the engine torque routed to the front wheels of a 996 or early 997 then the procedure is to drive agressively in a tight circle about 10 revolutions. With that much sustained disparaty between the F/R driveline rotation speed the VC will "stiffen" long enough for the average road course. The newest 997 now has an actual functional R/awd system using the same electromechanical clutch setup Ford has used, pretty much UNSUCCESSFULLY, in the Escape and Mariner. Now in use in the new FWD or F/awd 2011 Ford Explorer (yes, that says FWD & Explorer) but with water cooling of the PTO. With the C4S being R/awd the problems Ford has had are unlikely to affect the reliability of the Porsche version. Ford...STUPID...!!
  12. Thanks. It seems counter-intuitive at first glance, but now it makes sense. Anyway, I would think that the brightest combination would be a Red LED with clear lens, but would be more costly. You don't need diodes if you install LEDs in every socket in a given ciruit.
  13. Early Porsche C4 models using a VC, Viscous Clutch(coupling) have VERY little engine torque at the front wheel absent a SUSTAINED period of wheelspin/slip rear vs front. That level of sustained wheelspin/slip generally can only be attained with TC (PSM) off. The C4's additional traction capability is more often the result of rear engine weight bias rather than any significant level of VC coupling. That, of course, has changed now with the newer C4's making use of the Ford Escape electromagnetic clutch control technique.
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