Disclaimer

While the information contained herein is believed to be factual and correct, it's ultimate use is up to the reader. Also, where modifications are discussed, because the FAQ authors are not performing the modifications, they cannot guarantee or otherwise take responsibility for the fitness or success of the modification, should the reader choose to implement it. Use this information at your own risk.

Acknowledgements

Many Porsche 964 owners or enthusiasts have contributed their thoughts and ideas in internet user communities such as Rennlist and The Porsche 964 SmartGroup. Contributor's to the FAQ acknowledge that ideas and recommendations expressed in their contributions have in many cases have taken, or have been improved upon, from learnings acquired in participating in such forums. Contributions to the 964 are freely welcomed. Direct contributors to the FAQ include Bill Gregory, Bill Wagner, Jon Kaminsky, and material authored by Adrian Streather has been linked to where appropriate.

We hope it is useful! 

1. General Topics
2. Engine related topics
3. Drive train
4. Chassis Alignment
5. Brakes
6. Tires and Wheels
7. Suspension Upgrades
8. Track Preparation
9. Electronic systems
10. Air Conditioning
11. Audio system
12. Interior issues
13. Exterior issues
14. Appendix 1: Option codes

1-1. Is there a FAQ? Yes. 

1-2. What are some recommended sources of information?

1-3. What's the deal with this 964 thing anyway? I've heard everything from "problem car" to the best used Porsche value available.

1-4. How many different SKUs of the 964 series were there anyway? Any production numbers?

1-5. What are some good places for non-dealer Porsche parts?

1-6. What are the minimum items I should be thinking about when buying a used 964?

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2. Engine related topics

2-1. How do I check system fault codes?

2-2. How do I check the O2 Sensor?

2-3: What is the expected fuel economy for an adequately tuned 964?

2-4: What are the differences between the various engines in 964 variants?

2-5: What is contained in the DME EPROM and can "chipping" my car improve performance?

2-6: What are popular exhaust modifications and the expected performance outcome?

2-7: What are popular air-box modifications and the expected performance outcome?

2-8: What are the fuel quality requirements for the 964?

2-9: How can I "reset" the DME?

2-10: How do I access my DME (ECU) and change out the chip?

2-11. What are the symptoms of a distributor belt failure and how can I troubleshoot it?

2-12. What is the distributor "ozone" venting fix and how can I tell if I have it already?

2-13. What is the situation with the infamous cylinder head leak? What are the other potential places to leak oil?

2-14. When were the production changeover dates for the gasketed vs. non-gasketed engines?

2-15. Can and should I use fuel system cleaners and if so what is recommended?

2-16. What grade of motor oil should I use and can I use synthetic oil in my 964?

2-17: How often should I change my oil and what is the basic procedure?

2-18: How do you read the oil dipstick and the oil level gauge?

2-19. How much oil consumption is considered normal?

2-20. Should I remove the engine under tray?

2-21. My engine suddenly died. What are some possible things to check?

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3-1. How can I tell whether I have the Fruedenburg or the later LUK flywheel and when was the LUK cut into production?

3-2. What are possible options and potential problems with the lightweight flywheel or semi-lightweight flywheel upgrades?

3-3. My ABS and 4WD warning lights on my C4 have triggered on. What might be going on?

3-4. I am getting a "shudder" or vibration at high speeds. What could be causing this?

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4. Chassis alignment

4-1. What are the 964 alignment specifications for all non-Turbo models?

4-2. How can I reduce understeer?

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5-1. What should I know when considering a brake upgrade?

5-2. Can I replace the two-pot rear brake with the later 4-pot model?

5-3. Under what conditions do I need to change the proportioning valve for my brakes?

5-4. What can I do to reduce brake squeal?

5-5. What are popular brake fluid recommendations?

5-6. How do I bleed the brakes  and under what circumstances do I need to use the  Bosch Hammer?

5-7. What should I consider to make when replacing brake pads?

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6-1. What 17-in wheels will fit my car?

6-2. Are 18-in wheels possible on a 964?

6-3. What are "N" rated tires?

6-4. Under what circumstances are spacers required?

6-5. Can I mix and match tires?

6-6. What should my tire pressures be?

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7-1. What are the stock suspension component specifications for the 964?

7-2.  What are popular after-market shock/damper combinations for the 964?

7-3: What are popular after-market anti-sway/roll bar options for the 964?

7-4: What is the Porsche M030 suspension option and should I use it?

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8. Track Preparation

8-2.  What are popular tires for the track?

8-3.  I normally have access to only low-octane fuels. How much race gas do I need to mix in raise my octane for the track?

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9-1. My battery keeps running flat. What are possible causes for this?

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10. Air Conditioning/Heater

10-1: Can I use R-134 for air conditioning recharge?

10-2: What other "drop-in" replacements are being used in the 964?

10-3. I am getting no heat. What might be the problem?

10-4. I am hearing a light whirring sound coming from the dash area at regular cycles. What is causing this?

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11-1. What are popular audio upgrades for the 964?

11-2. How can I reduce/eliminate EMI noise in my newly installed stereo upgrade?

11-3. Where is the stock amplifier located in the 964?

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12-1. What are the possible interior colors?

12-2. How can I move my seat back further to accommodate my long legs?

12-3. My head is brushing the ceiling of the car. Can my seat be lowered?

12-3. How do I remove the front seats?

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13-1. What are the possible paint colors and codes?

13-2. My rear "wing" does not come up anymore or is stuck up. What should I check?

13-3. The grille openings under the front bumper have deformed. How do I straighten this?

13-4. My bonnet (front hood) keeps hitting me on the top of the head. What do I need to do to keep the bonnet up?

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Appendix 1: Option Codes

A1-1. What are the options for the 964 and the corresponding codes?

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