wwest

Sorry, but your boost gage MUST be lying.

In order to make most efficient use of forced induction the base/native engine compression should (MUST..?) be reduced from what would otherwise be optimal, 10:1 (12:1 w/DFI)base 7-8:1 (9-10:1 w/DFI). That results in fairly serious reduction in FE the 98% of time you spend "off-boost", simply cruising along. It seems to me that the best way to add boost at the rare times of need, or desire, would be a small bottle/tank of LOX. Our atmosphere is only 20% oxygen so adding another 20% of CHILLED oxygen would DOUBLE your engine's HP output.

ABS pumpmotor fluid pressure accumulator not holding pressure...

Purchased used..?? The A/C can be made a LOT more efficient by blocking the engine coolant to the heater core. Check to make sure some previous owner hasn't done that.

The VC itsself is ALWAYS hermetically SEALED so it is entirely possible that the design Porsche uses has the entire VC "case" fully sealed. Some VC's even have an inert gas under pressure inside the case. Gas "bubble" is used to delay the onset of VC coupling. So there may not be a vent/bleeder. Motto: If it aen't BROKE then DON'T fix it.

"01 C4 with ~24,000 miles. I measure (static/COLD) about 42 Ft/lbs required to turn a lifted front wheel with all three others on the ground. Correct, in the ball park..?

These big tires tend to make a lot of noise at that mileage because the tread wears off and it is like having two big flat pieces of rubber rolling down the road. I do not think soundproofing the inner wheel aprons is going to have much impact on that....But maybe someone knows differently. I usually feel lucky if I even get 8-10K from a set of tires :) Good luck. DC Current Michelins have LOTS of tread left, as did have the previous sets when swapped out.

~24,000 miles on my '01 C4 and now on the third set of tires in an attempt to get "quietness". Tires seem fine until about 8,000, to 10,000 miles when the tire noise becomes too intrusive. Thinking of using those spray cans of undercoat in the wheelwells and liners to try and quiet things down. Anyone tried this..? Any thoughts otherwise...?

Sorry, that's just PURE BS. The object of true DRLs is to have a vehicle driver quite some distance down the road be able to recognize an oncoming vehicle, even a vehicle in shadow. That's why the high beam bulb/reflector aiming system is most often used but with a low wattage bulb, W5W, or at a subdued voltage. The wide and low pattern of turn signals is NOT DESIREABLE.

"..operates normally now..." Car starts, runs, radio operates normally, etc, etc........ In other words if you weren't now "watching" the charging rate/voltage you would have no idea of something being wrong....

Assuming the one you're taking out has failed in some manner disconnecting the battery will result allow a quicker ECU learning process starting from the factory default parameter.

The battery was less than 1 year old when the trouble began. Since it was still under warranty, I swapped it for a brand new one before making my original post. Needless to say, it wasn't the battery. I have a new regulator coming so I am going to try that next. if I follow this correctly everything now operates normally.... Are you certain you're not troubleshooting a non-existent problem? Using a DVM, Digital Volt Meter, with the engine idling, measure the voltage on the battery posts vs the jumper point in the engine compartment. A difference of more than 0.5 volts might indicate a poor wiring or ground connection front to rear. The alternator might be "generating" a proper battery charge voltage, ~13.5 volts, but only charging the battery to ~12 volts.

That's strange, my lawn tractor battery charging system acts the same way. Immediately after starting it the charge rate, current flow and voltage, goes up. Within a few minutes the charge rate declines as does the alternator output voltage.....Strange....? NOT...!! SOP....!! And a "cold" battery will accept/require/indicate a higher charge rate and voltage. You undoubtedly have a dead cell in your original battery. terminal

Parts to do this are <$2.00 at Radio Shack.

When it arrives jsut toss it into the trash bin and go to ebay and buy a donnelly rear view mirror with right and left map lights included.

Yes, you can...but why..??

The DEFINITIVE answer(s)... 12:1 compression ratio with DFI, higher compression results in more blow-by. Notice the complaints about higher oil consumption for new, non-broken-in engines...? Higher DFI compression over "normal", historical normal, results in more blow-by during the compression stroke. Rings must more fully seat before oil consumption declines. PCV passes the crankcase blow-by oil "mist" to the intake, some of the "mist" deposits on HOT intake valve backside and congeals there. Part of the mist enters the cylinder along with the "air" charge, no fuel yet for the mist to intermix/atomize with, so the mist simple deposits on the rising piston head. Increased compression with DFI requires improved pistion/ring/cylinder wall sealing or else you end up with congealed oil deposits on the intake valves and soot on the tail pipe. Porsche says oil consumption should decline substantionally once the engine is fully broken in, 3000, 4000 miles, my assumption is that means once the rings are more thoroughly seated.

Or... The evaporator will NOT freeze up if the control switch is working/installed correctly because it will interrupt the current to the compressor clutch before, ~35F, the evaporator cooling vanes reach a freezing temperature..

The only control point I can find, discern, on my '88 Carrera is the capillary thermostatic switch that is used to control the temperature setpoint of the evaporator/evaporator airflow. If the capillary tube/bulb is not installed correctly, buried, within the evaporator cooling vane area the evaporator could freeze up and that would result in a failed compressor due to slugging. Since the thermostatic switch seems to be so highly prone failure, failure in a way that results in the compressor running continuously, what provisions, if any, did Porsche make to prevent this type of escalating failure...?

In my opinion the early 911 A/C system design parallels the one in my MH, or even a typical window A/C. The only control point is the temperature of the evaporator vane surfaces or the airflow through those surfaces. So what happens if that control point fails in a manner wherein the compressor runs continuously...? In my MH or the typical window A/C the house circuit breaker might open, or is more typical the CB inside the compressor drive motor opens due to heating of the windings. Now the CB cycles every 5-7 minutes until the refrigerant pressure declines to the point that the motor will restart without tripping the CB. So, what happens when the control system in these early Porsche A/C fail in the same manner, how did the Porsche factory design prevent subsequence damage to the compressor due to "slugging", liquid refrigerant reaching, entering the compressor inlet. Or did they just ignore the issue..? Is the clutch designed to begin slipping with too much refrigerant pressure? Is the compressor itself of somehow a design that limits downstream pressure? A spring loaded relief valve, Pressure CB, that ports downstream pressure back into the inlet if pressure rises too high...? Or is the factory recommended refrigerant charge intentionally low enough that the compressor running continuously will not, will NEVER result in slugging? My advice to anyone is that BEFORE you begin upgrading your factory A/C you should either find a positive answer to one of the above questions or add a hi/lo pressure switch downstream of the compressor so the (old/ new) compressor doesn't inadvertently destroy itself.

Most states, like mine, WA, require in state registration within 30 days of purchase or "bringing" a car into the state of primary use/residence. Get caught = get FINDED.

wwest, Sounds like there may be some air-bubbles in the radiators in the front of your car?? Have you recently changed your coolant?? You might want to run for a day with the coolant bleeder valve open to help "burp" any air pockets in the cooling lines/radiators. Do a search in this forum for lots of info relative to purging air from cooling circuit. Good Luck!! demosan :cheers: Coolant bleeder valve...? And no, coolant hasn't been touched since the factory. Is it possible to have the coolant left in the engine boil shorty after shutdown..?? I had parked the C4 outside and went back later, 10-15 minutes, to move it into the garage. The gurgling noise happened as I shut the car down after moving into the garage. I could repeat at the time but now doesn't seem to happen. Air bubbles in the coolant temporarily due to boiling.....?

wwest, Sounds like there may be some air-bubbles in the radiators in the front of your car?? Have you recently changed your coolant?? You might want to run for a day with the coolant bleeder valve open to help "burp" any air pockets in the cooling lines/radiators. Do a search in this forum for lots of info relative to purging air from cooling circuit. Good Luck!! demosan :cheers: Coolant bleeder valve...? And no, coolant hasn't been touched since the factory.

2001 C4 yesterday evening after I shut the engine down I hear a "gurgling" sound coming from the very front of the car, coolant reservoir is full. Don't remember ever hearing that sound before. Anyone know the probable source..??

You can buy LED bulbs to replace the standard incandescent ones.