wwest

Hey wwest - when I put the led bulbs in for my brake lights, my center led brake light no longer worked. Switched it with my stock one and it works. Is this a resistance issue I've heard about with turn signal bulbs?

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I like the look of LEDs. Not sure if LED tail lights exist for the 996.

Complete LED bulb set in my 2001 C4 from V-leds, velocity leds on ebay.com, even markers.

No, I had no problem as you describe.

I originally used individual LED lamps in the factory center mount brake light assembly and discovered that the cruise control did not work because LEDs always drop 0.5 to 1.2 volts. I added a small "dip" relay and a 50 watt 12 volt halogen bulb. The bulb is in the circuit, dropping the brake circuit "keep-alive" voltage to virtually zero, only when the relay is not energized. When the factory LED high mount became available I simply snapped it in.

The turn signal flasher relay is yet another story.

It has a solid state controller built in. A current sensing link is used to detect a turn signal bulb failure so you get the FAST flash you would expect. You have to open the flasher relay assembly and replace the current sensing link with a low ohm resistor of the correct valve.

The only difference I can think of is that I have 4 LED brake lamps that come on with braking. I added the "backup" light fixtures, both sides, to the brake circuit to give better "notice" that I am on the brakes.

I like the look of LEDs. Not sure if LED tail lights exist for the 996.

Complete LED bulb set in my 2001 C4 from V-leds, velocity leds on ebay.com, even markers.

2001 C4 110k km Canadian car

The car should have daytime running lights because it is a Canadian car but all the lights are on with the headlamp switch in the off position. Headlights tail lights etc. When I move it clockwise to parking lamp position the interior gauge lights come on, in the night time position there is no change all lights remain on. The headlamp switch doesn't turn anti-clockwise to the rear park position. Any suggestions on what to check?

P.S. update on the "dead" radio issue I had, the is a 10 amp fuse on the backside of the radio where the harness plugs in that had failed, the radio works now, which is a good thing because I can't hear the front end rattle anymore !!!

That's SOP, absolutely normal, for Canadian DRL specifications.

After owning a 99 of Canadian origin I modified my 2001 C4 to operate the street/parking/tail/DRL lamps the same way. Except the '01 has specialty european 5 watt halogen DRLs instead of using the HID headlamps. I replaced the 5 watt halogens with 3 watt Luxeon LEDs with a collimator lens.

There are fairly common instances wherein a non-vented battery can be EXTREMELY DANGEROUS, especially where this one is located.

It is not altogether unusual for the voltage regulator to fail in a way that results in SEVERE over-charging of the battery, so much so that the battery electrolyte begins to boil and vent gas. Gasses not only hazardous if you breath them but also EXPLOSIVE. Even more common might be a shorted cell within the battery in which case the regulator tries to charge the 5 remaining 2.25 volt cells to a full ~13 volts.

So...

Be sure, absolutely SURE, your battery is vented.

Are you talking about the center tail light above the spoiler? If so use a small screw driver to gently pry the cover on the right side of 3rd brake light then use that screw driver to turn the twist lock 90 degrees. Once removed unplug the wire. Cool?

the whole tail light

The only incandescent lamps left in the back of my 2001 C4 are the backup lights and even that was upgraded to 50 watt bi-pin halogen landscape bulb on the driver side. Front street/parking lights are LEDs, green LED normally flashes amber with front amber LED turn signal. DRL "bulbs" are also LEDs, 3 watt Luxeons with collimator lens.

Cruise control will not work with all LEDs at the rear unless it sees a high current load when the brake lights are off. Minature (dip) 12 volt relay normally closed contacts supplying "power" to halogen bulb only with brake light off solved that problem.

i have a ? my reaer passager side fog lights don't for some reason i check the fuse and the light bult and it fine any idea

Rewired both of mine so that they come on with brake application. Like high mount brake light this draws more attention to the fact that I'm on the brakes.

Does anyone know if traction control on a 1999 C2 works at all speeds? For instance, if you mash the throttle at the apex of a sharp corner, will TC prevent the tail end from breaking loose? How does TC compare to the PSM system?

Just FYI, in case you were unaware, if you have the traction control option on a 1999 model C2 your car is also equipped with a mechanical LSD (Limited Slip Differential). The '99 C2 was the last normal (not GT3) version of the 996 with this feature. My '99 996 was so equipped. It was great for autocrossing; I could turn off the electronic traction control which tended to cut the power at inoportune moments, yet I still got the benefit of enhanced traction with the LSD.

This is great info. My early 99 has TC as I see a button to turn it off. I never knew I had LSD until now!

BTW, I should have mentioned one additional fact; the info on the mechanical LSD applies only to 6 speed manual equipped cars. If you have a 6 speed and TC you and your LSD are good to go!

Are you really sure of that '99 TC/6-speed LSD issue?

I had one but I don't think it had an LSD, mechanical or virtual.

If you change to a K&N air filter, or swap out your factory air box for one of those cold air intake kits with the cone-type air filter, be sure to DISCONNECT THE BATTERY before you start the car again. Doing this can help prevent your CEL (Check Engine Light) from coming on.

Why? Because disconnecting the battery "resets" the engine computer. When the battery is reconnected, the engine computer will start learning from scratch, with the new, higher-flow air intake. If you do not purge the computer's memory, it will detect a sudden change in the intake air, and this can trigger the CEL.

You can disconnect the battery for up to 20 seconds and not have to re-input your radio codes. But for this type of change, be sure to leave the battery disconnected for at least 50 seconds. This will purge the machine.

Be careful how much oil you put on the filter. You may want to oil the filter, and then leave it standing on end for 2-3 days. Wipe up any excess that collects under the filter, and blot the part of the filter closer to the ground to be sure you won't be dripping any filter oil into your intake. (If you stand the filter on end for a couple of days and you get some drips, you're using too much oil...)

I've had a factory K&N installed in my '99 C4 for 15k miles so far. There may be a couple of HP there, but for me, I like the reduced cost and environmentally friendliness of a re-useable filter.

Dan

"..., it will detect a sudden change in the intake air....."

Really...??!!

If you completely removed ALL intake filtering it would only be effective, make a difference, at WOT and at or near the RPM and engine "loading" wherein peak intake airflow occurs. Otherwise the throttle butterfly valve itself is the MAJOR restriction to intake airflow.

And even should you immediately do so, at WOT and maximum intake airflow, do you really think the engine ECU will see the slight difference in airflow restriction?

NOT...!!!

So, just what do you get with a K&N vs an OEM filter.

1. NOISE....!

2. Possible MAF/IAT sensor module failures.

3. Possible premature engine failure.

May I suggest a simple test that could also be used as a "burn-in" procedure for those of you who still insist on using a K&N or the like?

Use a home vacuum cleaner to provide a means of wicking the inadvertent over oiling off of the K&N.

After you CAREFULLY oil the K&N put it in the vacuum path with a new vacuum filter and after an hour look to see how much oil has been wicked from the K&N and onto the vacuum filter.

Go to TeamSeattle.com and fill out a lap pledge to benefit Seattle Childrens Hospital. Then watch, with "interest", two beautifull and well race prepared Porsche GT3's compete in the 24 hours of daytona.

Something inside the tire itself..??

What kind of tires are you using? That plays a much bigger part than any electronic nanny or awesome drive train you have. If you don't have snow tires on, your not going anywhere.

I am running Pirelli P-zero tires.

If there was torque to the front wheels, they weren't moving/spinning.

The rear wheels were constantly spinning.

Sounds like the car responded as it was designed and that the AWD is really for cornering, not for traction on a slippery road. I have a 2nd vehicle that is good in snow, so the C4 may stay garaged when the storms roll through. This last blizzard was the worst we've had in years.

Thanks for the information.

I may try BLIZZAK tires when the Pirelli's wear out.

Tacky question, but from the driver's seat how do you know the front tires weren't turning...??

And don't forget that since there is no "virtual" LSD for/at the front (open diff'l) the right front tire might have been spinning wildly while the driver's side was stationary.

Also,with the rears spinning, LOTS of noise, you may not have been able to discern the much lesser noise from the front with so little torque/traction.

Sorry, it was my wording in response that resulted in confusion. The "flasher" that I have seen and was comparing yours to blinks the light rapidly for two seconds and then comes on solid. When I installed LED lamps in all of the rear light fixtures my cruise control stopped working so I had to simulate an incandescent filament load when the brake lights were off. I did that with the NC contacts of a small 12 volt "dip" relay and a 12 volt 50 watt halogen bulb.

The viscous coupling is just as it sounds. It uses fluid to transfer power to the front. Kind of like a torque converter. The only difference is that the fluid would thicken as temperature increases when there is slipping between the two turbines. In cold weather, this almost doesn't thicken. 5% of the torque is only about 15 ft lbs at peak. Even at the full 40%, your talking 100 ft lbs.

What kind of tires are you using? That plays a much bigger part than any electronic nanny or awesome drive train you have. If you don't have snow tires on, your not going anywhere.

Subaru AWD uses a transfer case. Very much like a normal differential. It's actually very backwards like a truck. With that said, it's a lot more "useful" in getting you going in the snow. WRX and EVO just added clutch packs to the diffs and use electronics to control the engagement. The 4WD in the P-cars are not designed for this purpose. It's to assist in cornering. That's why they drive like a RWD car. The 997 C4S is actually quicker around the track than a CS. They do share the same AWD system with the 996.

The 997 turbos does change this to a system similar to the WRX and EVO which allows the engineers to control things electronically.

There is nothing wrong with your system. Get some good snow tires. Narrower the better. You'll be able to get around.

IMMHO cold weather, climate, will have little effect on the rate at which the viscous fluid heats and "thickens" (actually becomes compressed due to the inability for the HEATED volume to expand in the fixed volume hermetically sealed VC case) to increase the coefficient of coupling to the front.

There is NO snow tire of any type that would have helped you move forward on an incline on a surface as slippery as you describe.

If you MUST drive your C4 in those conditions then tire studs or tire chains will be the only reasonable solution.

My 2001 AWD RX300 runs on nice quiet and comfortable summer tires, Bridgestone Turanzas, all year around. There is ALWAYS one set of easily installed tire chains in the spare tire "well" and durng the winter months I always have a second set on board. If I had a need or a good reason to have the C4 out in that kind of weather I would keep my standard tires and rely on tire chains if/when the need arises.

Need easy access to wiring of 3rd brake light for installation of this brake light flasher:

http://www.thompson-automotive.com/catalog...157/2549509.htm

Tried to reach wiring by removing the 3rd brake light from its enclosure at the rear wing, but the fit is too tight to reach any of the wiring. Can I reach the power wire anywhere else in the car, where this flasher can be tucked away neatly? If this is possible, I can have the 3rd brake lights (one seen with wing down, and the other one which is visible with the wing up) flash 3 times, then come on steady. Maybe prevent a soccer mom w/cell phone from ramming my car.

TIA for opinions/comments.

Alex

1999 996

The relay and halogen bulb I needed to install to keep my cruise control working with all LED brake lamps is mounted right to the back of , and wired within, the 3rd brake light assembly itself. An equivelent flasher can be purchased at autolumination.com for ~$5.

While you're in there you might consider also wiring the otherwise useless rear fog light(s) into the brake light circuit to give an even more pronounced indication that the brakes are being used.

If I am stopped on a hill on ice & the rear wheels spin constantly without the front wheels pulling, is something broken on my car or is this a normal response?

I think it is a "normal" responce. As I understand the 4S system is not anywhere as advanced as AWD on either WRX or EVO. It is also not designed for "heavy" slippery driving. It is good in the rain and adds some perfomance, but it doesn't make a car a good ice driver.

Once the ABS pumpmotor is timed out that would be a normal response only if the VC is non-functional for some reason. In the alternative how sure or you that the front wheels weren't "driving" (also "slipping" on the same slippery surface) and torque limited due to the continuous slipping of the rear tires?

We got a HUGE snow storm today & I got stuck several times in the C4 today on the way home...so I need to bring this thread back to life:

1. After continual slipping up a 1/2 mile incline (I kept going 2-3 mph, but with wheel slippage) using PSM & the warning light on most of the way, with me keeping on it with a steady throttle to keep the momentum up a snowy/icy hill, the PSM turned itself OFF, the ABS light came on. I got stuck a few seconds later. Is this normal? Is there a way to keep PSM on during a prolonged duration of slipping/sliding to get grip to climb a hill?

2. Shortly after the ABS/PSM OFF lights came on, I got stuck & the engine died. After I started it back up, I got stuck (on another genlte incline) & I got passed by a subaru with all wheel drive. When I was stuck (not with snow, but mostly slipping on ice), I seemed to only have rear wheel drive - the rears would spin, but the fronts wouldn't spin. I am wondering if I need to "reset" the viscous clutch so I have all wheel drive again? With the subaru passing me, it seemed pretty clear I didn't have all wheel drive or I wouldn't have been stuck. The subaru stopped & was able to start moving again on the same slippery road I was on, so I'm pretty sure there was no power to my front wheels.

Any advice/technical data is appreciated. Thanks in advance.

1. All of the PSM auxiliary functions that apply the brakes use pressurized brake fluid supplied by the ABS pumpmotor assembly. This pumpmotor is a relative small fractional HP 12 volt DC motor and typically cannot be operated continuously or semi-continuously without overheating. So most of these systems have a timeout for the ABS pumpmotor to prevent its failure due to overheating while reserving some level of operating capacity for actual ABS. The one in my 2001 AWD RX300 will come back online about a mile or so down the road if I recycle by restarting the engine.

2. There is no "reset" of the VC. The VC will not come into "play", dramatically increase the coupling coefficient, typically, absent an extended period of rear wheelspin. Which, by the way, the traction control system will act to prevent.

Sorry, that's just the nature of the "beast". In my experience driving a Porsche in the snow, C4 or not, is a matter of mastering the art. Starting off in 2nd or 3rd gear, carefully feathering the throttle to prevent wheel slippage, etc.

My 2001 AWD RX300 runs on nice quiet and comfortable riding summer tires, Bridgestone Turanzas, all year around. When winter approaches the tire chains are always onboard and are quickly installed, all four, at the first indication of need. My C4 stays at home in a nice warm garage where it belongs.

As you have just discovered the Porsche C4 is not an adequate (not even close , actually) AWD setup for severe winter roadbed conditions.

PS: You don't say if your C4 is a manual transmission or not, if it isn't it should always, most definitely, IMO, stay in the garage in those conditions.

Thought this would be simple but...

My cruise control would not engage since the sensor indicated the brakes were always applied. Cruise control is always disabled when you even touch the brakes lightly. LED stop lamps/bulbs do not draw enough electrical current to satisfy the cruise control "brake not applied" sensing current. Solution was to use a 12 volt relay to connect a 50 watt halogen bulb as a load on the brake light circuit when the brake light are off.

Turn signal LEDs turned out to be a horse of a different color.

Although the 2001 996 turn signal flasher is solid state the turn signals went into a FAST FLASH mode indicating a failed turn signal lamp. I had to open the turn signal flasher relay and change the electrical current flow sensing resistor, actually a nichrome wire link, such that it still dropped ~0.20 volts with both low(er) current LED lamps operational. So now it will still "fast flash" if one lamp fails.

The 996 C4 uses a VC, Viscous clutch, in "series" with the driveline to the front diff'l. It is my understanding that the VC is always "stiff" enough to couple about 15% of the engine drive torque to the front diff'l but the coupling level will increase to as much as 45% if the rear tires slip/spin for an extended period. The VC does not react instantaneously to rear wheel slippage.

Additionally you have a "virtual" rear LSD, Limited Slip Differential in that the rear brakes will be applied, differentially, to the wheel/tire with the most slip/spin.

On top of all that you have traction control which will apply braking to BOTH rear wheels if they both slip/spin. I haven't encountered such a condition but I would imagine that the engine would be dethrottled within a few hundred milliseconds if the rear wheelspin does not abate or the driver does not react and lift the throttle on his/her own.

I did this. my post on rennlist. The pictures are gone, I can send them to you if you like.

This information is based on my '01, I did this in late '02/early '03. Some things may have changed.

The pictures are gone, if you are interested, I can hook you up. The basic gist of it is:

If you want to use the stock controllers, you should use the sock elements.

The elements are not embedded in the foam. The heating element for the lower seat is sold as a stick on. It has to be cut in half for the two lower GT3 seat cushions. This is not hard. The upper element is sold attached to the seat cushion. It can be liberated with a hair dryer.

Contact me if you want more details.

BTW, these are GREAT on a late fall or early spring track day, when the windows must be down!

A friend of mine wanted to add seat heating to his 1998 Lexus LS400 to save his marriage. His previous LS had heating but he traded up....

I purchased at least three heated cushion sets off of Ebay before coming to the conclusion that the heating elements could not be removed from the cushions without damaging them. So I purchased add-in heating elements off of Ebay, installed them in the existing cushions, and saved his marriage.

What might be my chance of success in transplanting the hybrid drive system, ICE, MG1/MG2, etc, from a wrecked FWD Prius to a RWD Cayman, keeping the Cayman's RWD aspects?

Then recover some of the Cayman's "GO" by adding a SuperCharger driven by an A/C motor using a variable frequency drive powered by the 270 hybrid battery.

What do yawl think...?

Some of them ARE boy-racers, LITTLE BOY-racers.

what is the best prevention method?

IMHO two things.

One - always turn the air off a couple miles from home so that the moisture that has condensed on the coils can evaporate off.

Two- make sure that your drain tube from the evaporator is not plugged and the moisture flows to the ground.

One...During A/C operation the evaporator surface temperature is kept as close to 32F as is possible, typically <35F. So it can take up to an hour, depending on climatic conditions, after the A/C is shut down before the evaporator surface area rises above the dewpoint of the "local" atmosphere. Additionally if some method is not provided for at least some level of convection airflow once the moisture begins to evaporate it will still remain within the A/C plenum.

Two...Agreed, absolutely! But a plugged drain tube usually results in a wet carpet on the US passenger side.

First, go to airsept.com and read the material regarding their EED, Electronic Evaporator Dryer.

The best way to avoid this problem, and occassional fogging of the winshield the next morning after having used the A/C the previous day, is to lower the windows and open the skylight during the night in the garage.

Presonally I installed a switch in line with the A/C compressor clutch circuit so I could prevent the A/C from activating unless I actually needed cooling.

996 C2 1998 Silver

I have just seen that bird crap on my spoiler lid has actually caused the paint to blister and peel off, it is about 1cm across and then a smaller patch next to it. The picture does not really show the detail, but the paint underneath has curled up and will come off when I clean this. Is there an easy repair? I have a silver touch up pencil, but the area is quite large.

Thank you for any advice.

Porsche repainted my GT3 style spoiler three times because the paint kept bubbling, finally replaced it with a new one and I'm awaiting results. I suspect the underlying fiberglas was not properly cured.

I have 4 cars (2 porsches) and my 996 aero is a street only creature. Brake dust on my nice 3 piece wheels is becoming increasingly bothersome with the stock pads. Does anyone have any suggestions for pads that provide OEM-like friction coefficients but are extremely low dust? I don't need track or autocross performance and fade is not an issue on the street, so OEM grip and low dust are the primary factors. I have been considering the Axxis Deluxe (organic) and Axxis metal master and the Hawk Performance Ceramic. I'm upgrading to cross drilled AND slotted Brembo rotors, so initial bite will be enhanced slightly.

I agree, dust on 3-pc wheels is a huge pain!! I have been using the Hawk Ceramic pads for low dust and been pretty happy with them.

Good Luck.

-SD

Thanks guys. I was considering the Hawk Ceramics anyway and it's cool to get some validation. Note: When I mentioned I am upgrading rotors, I meant that the new Brembos will be crossdrilled AND slotted. Slotting is supposed to burnish the bad continuously and create a more aggressive friction surface, not just help vent gasses.

Personally I want brake pads that EAT rotors for lunch. One NEVER knows when quick stopping might mean the difference between being able to next remove and clean those BBS mesh wheels or not.