Early 964 owners. I have a ?

[toddh]

I appreciate the perspectives on this thread. My '91 C4 has been great. Given everything I have heard, any suggestions on how to make it better?

If you had this car and a blank checkbook - what would you do?

[budge96]

Sell it and get a twin turbo! Oh sorry just joking, maybe look into a secondary bypass pipe
and or a cat bypass and a chip.
It could help emmensly, better tires and larger wheels can inhance turn in and feel, and a
few suspension upgrades never hurt anybody.
Likely it depends on what you want to do with the car and how long you plan on owning it.
DE/Auto XX and other events may require more disassembly and dismantling of originality
than you care to repair when you want to sell ,some of that stuff ends up being irreversible,
but usually as long as original parts are kept ..modifications can ba reversed.
Bert

[davisriley]

Want to make it better? Make the driver better. Go to some de's, autocross's, just get it on some sort of track. You will be amazed at what the car can do stock. And then decide what direction you want go. Good luck.

[toddh]

you would run this stock on the track? i guess i have been reluctant to push it but that is probably exactly what i should do.

i like the idea of the bypass pipe.

so i understand, you suggest that with any changes i make sure to keep the original parts to make sure that it can be brought back to stock?

[tshih]

With comments from Bruce Andersen about the complexity and costs of repairing the 4 wheel drive C4 system (959 derived) I would suggest that those with C4 964 might want to investigate turning the car into a C2 when repairs are needed.

[Hawktel]

Tshih,

My understanding is the 4 wheel drive on my car wasn't from the 959, but from the 953, Paris Drakar racers of 1984.

The 959 was also developed from that car, but the C4's of 89- on used a different system than the 959.

I think the failure you experience on the front 4 wheel drive would be the deciding factor for me on if I fix it.

[toddh]

Can you point me to further info on the C4 to C2 conversion. Any sense of what it might cost?

[mjshira]

Originally Posted by Tyson Schmidt

I also work on these cars everyday. What I have noticed is that the cars which still have the undertray in place have valve guide wear far greater than those that have it removed. It is usually the exhaust guide on cylinders #2,#3 and #6. (#2 & #3 are close to the catalytic converter, and #6 is furthes from the fan.)

Keep in mind, this is in Southern California where it is hot and traffic is horrible! The undertray isn't an issue at all in the hottest of climates, so long as the car is moving at a decent clip. Traffic just cooks these motors with the undertray in place.

This also causes more oil leaks due to the seals and o-rings basically cooking themselves. They usually feel just like plastic.

But I totally agree that these cars have gotten a very bad rap. It seems that everyone needs a car to pick on. SC and Carrera owners love do rip on the 964, but it is a better car in every way than either of them. People who have never owned a C2, or even driven one, will chime in about it's supposed problems and shortcomings. Pure crap. Better car in every way. And I've driven dozens and dozens of examples of each model.

The C2 and C4 are the absolute bargain of the century right now. Look at the performance numbers. They are a supercar. They are also rock-solid and reliable. My only complaint is that my insurance is just ridiculously high.

I agree with Mr. Schmidt here. I run HeatSheets on my 964 just for this reason. It helps a great deal in keeping heat off the heads. Also, the engine heat sheild stuff seems to hold more heat near the engine then it keeps it away. I deleted mine. There are great cars when dialed in. These cars are cheap for what you get, check out mine in the for sale section

[tshih]

The consensus about the costs of converting a C4 to C2 in the 964 series has been discussed and the opinion of Bruce Andersen (in Excellence magazine technical Q/A) is that it is prohibitive enough to warrant selling the present running car and buying an OEM C2. I'm sure someone has done (the conversion) since the C4 may be in better condition than the C2 that someone else may be selling and after the expense of making the software change (ECU ABS electronic clutch differential, etc) i.e. new DME, wire harness, new C2 gearbox, maybe shifter rod needs modification) are things that are different from all wheel drive to rear wheel drive. Joel Reiser of Reiser Technik should be able to tell you what is needed to do the conversion see www.reiser-technik.com and email him for costs estimate.

[toddh]

Originally Posted by tshih

The consensus about the costs of converting a C4 to C2 in the 964 series has been discussed and the opinion of Bruce Andersen (in Excellence magazine technical Q/A) is that it is prohibitive enough to warrant selling the present running car and buying an OEM C2. I'm sure someone has done (the conversion) since the C4 may be in better condition than the C2 that someone else may be selling and after the expense of making the software change (ECU ABS electronic clutch differential, etc) i.e. new DME, wire harness, new C2 gearbox, maybe shifter rod needs modification) are things that are different from all wheel drive to rear wheel drive. Joel Reiser of Reiser Technik should be able to tell you what is needed to do the conversion see www.reiser-technik.com and email him for costs estimate.

I appreciate the info. It sounds like "if it ain't broke, don't fix it" but if it does break, go for the OEM conversion.

[304065]

Read the recent article by Joel Reiser in Panorama that describes the difficulties of repairing the 964's AWD system. The complexity of the earlier system combined with extremely high prices for repair parts that cost more from Porsche than the car, this is the most significant issue to consider when thinking about a C4. Leakage? No problem. Clutch? No big deal. Distributor? Kid stuff.

[bcoats]

my car doesn't have an engine cover, but still has the heat shields near the valve covers, should these be left on as the cat get very hot? Or can they be removed but modify or delete the cat? I am in the northwest and really never gets too hot here, so maybe doesn't really matter?

[mjshira]

I can only offer what I've done as an option to consider. I run HeetSheets and that kills a lot of heat from exhaust to engine head transfer. When I had a cat it was wrapped in heat tape (the stuff you put on headers or exhause manifolds) but eventually I elected to ditch the stock system for aftermarket headers. These I had ceramic coated. This process made a moderate improvement in heat reduction.

As has been said, if you are moving and air can pass over the engine, then 9/10 times you'll be ok anyway. Given where you live it rains (and rains and rains and rains) you'll probably not need to to anything.

Hope this helps! good luck

oh and BTW, my folks live in the Seattle area also, this is why I know from experience about the rain there ;-)

[bcoats]

thanks for the feedback, yeah, Seattle kind of sucks that way, not sure why I live here in all honesty. . .