Porsche 993, Frequently Asked Questions

Buying

Why is the 993 so expensive?

One word: finality. The 993 is the last air-cooled 911. When Porsche switched to the water-cooled 996 in 1998, the thirty-five year lineage of air-cooled flat-six 911s ended permanently. That status as the final expression of the original 911 formula has driven demand relentlessly since values began climbing around 2012-2013. A car that traded for $40,000-60,000 AUD a decade ago is now $150,000-250,000+.

Beyond the “last air-cooled” cachet, the 993 is genuinely an excellent car. The multilink rear suspension transformed the 911’s handling, the body design is arguably the most beautiful 911 ever, and the VarioRam-equipped flat-six is the pinnacle of naturally aspirated air-cooled Porsche engineering. It is not just historically significant, it is a brilliant thing to drive.

What is the best 993 variant for the money?

The Carrera manual coupe is the entry point and, in many ways, the purest 993 experience. It is the lightest, most driver-focused variant, and it captures everything that makes the 993 special without the premium attached to the wide-body cars. A clean Carrera manual coupe in the $170,000-220,000 AUD range with documented service history is the smart first buy.

If you can stretch the budget to $220,000-280,000, the Carrera S (wide body, rear-wheel drive, naturally aspirated) is the car most 993 enthusiasts consider the sweet spot. Turbo looks, Turbo brakes, naturally aspirated simplicity.

What is the difference between the Carrera S and the Carrera 4S?

Both use the Turbo’s wide body shell with the naturally aspirated VarioRam engine. The Carrera S is rear-wheel drive; the Carrera 4S adds the viscous-coupling all-wheel drive system. The 4S is approximately 50 kg heavier, offers more traction in wet conditions, and feels marginally more planted on the rear axle. The S is lighter, slightly more engaging through the steering, and preferred by drivers who value purity over all-weather security. Both are exceptional cars. The 4S commands a modest price premium.

How do I tell a genuine Carrera S/4S from a standard Carrera with a wide-body conversion?

Wide-body conversions exist and are sometimes passed off as factory S or 4S cars. The genuine article can be verified through:

• Porsche Certificate of Authenticity: Ordered from the Porsche Museum in Stuttgart ($200 AUD approximately). This document confirms the car’s original factory specification.
• VIN decode: The 993’s VIN encodes the model variant. An S or 4S has a specific model code in the VIN.
• Build details: Factory S and 4S cars have Turbo-spec brakes, specific suspension settings, and model-specific trim. A conversion typically lacks some of these details.

Always obtain a Certificate of Authenticity before purchasing a high-value 993 variant. The cost is trivial relative to the price difference between a genuine S/4S and a converted narrow-body.

Should I buy a 993 Turbo?

If you want the ultimate 993 driving experience and you can afford the purchase price and ongoing maintenance, yes. The Turbo is one of the great supercars of the 1990s, and its twin-turbo engine provides relentless performance that remains genuinely fast by today’s standards. The all-wheel drive system makes the performance usable in all conditions.

The Turbo costs more to maintain than the naturally aspirated cars. The turbocharger system, intercoolers, and the additional plumbing add complexity. Turbo-specific services include checking boost levels, inspecting wastegate function, and monitoring the turbo bearings for play. A turbocharger rebuild costs $3,000-5,000 per side. But a well-maintained Turbo is no more troublesome day-to-day than any other 993.

The Turbo is also the relative bargain in the forced-induction 993 hierarchy. A good Turbo is $320,000-400,000 AUD. A Turbo S starts at $500,000+. A GT2 starts at $700,000+. The standard Turbo offers 95% of the performance at a fraction of the price of the rarer variants.

Manual or Tiptronic?

Manual. Always manual for a 993. The four-speed Tiptronic automatic is slow, robs the car of its character, and is worth 15-25% less than the equivalent manual. The Tiptronic valve body can also develop expensive faults ($8,000-15,000 to rebuild). The six-speed G50 manual gearbox is robust, precise, and integral to the 993 driving experience.

The only exception is if you physically cannot operate a clutch. In that case, the Tiptronic 993 is still a wonderful car, and the price discount represents good value.

What is the Nikasil bore issue, and should I be worried?

Early 993 engines (predominantly 1994-1995 production) used Nikasil-coated cylinder bores. Nikasil reacts with the sulphur in fuel, and Australian fuel in the 1990s had relatively high sulphur content. Affected engines develop bore scoring, lose compression, and eventually fail.

Not all early 993 engines are affected, it depends on the fuel history of the specific car. Later cars (1996+) switched to Alusil cylinder liners, which are immune to this problem.

For any pre-1996 993, a compression test, leak-down test, and bore scope inspection are essential before purchase. If the bores are healthy, the engine is fine. If they are scored, you are looking at a $15,000-25,000+ engine rebuild. This single issue is the reason a pre-purchase inspection is non-negotiable on any 993.

Are 993 parts available?

Yes, the 993 is well-supported. Porsche Classic (Porsche’s official heritage parts division) stocks a wide range of parts for the 993. The aftermarket is also extensive, companies like Design 911, Pelican Parts, Stoddard, and Paragon cover mechanical, body, and interior parts. Many suspension and brake components are shared with or adapted from later 911 models.

Engine internals (pistons, cylinders, bearings, gaskets) are available from Porsche Classic and from aftermarket suppliers like Mahle and LN Engineering. The 993’s status as a high-value classic means that the parts supply chain is well-established and will remain so.

Australian Porsche specialists carry commonly needed parts, and international orders typically arrive within 1-2 weeks.

Driving and Ownership

Can I daily drive a 993?

Technically, yes. The 993 is the most refined air-cooled 911, with comfortable seats, decent climate control (the heating is good; the AC works when the compressor is healthy), and a ride quality that is firm but not punishing. Many owners do drive their 993s regularly.

Practically, most 993 owners treat the car as a weekend and special-occasion car rather than a daily commuter. The reasons are partly practical (the car is now 25+ years old and does not have modern safety features, traction control, or the mechanical resilience to shrug off the abuse of daily city traffic) and partly financial (every kilometre adds wear to a car that is worth $150,000+, and the running costs, fuel at 14-18 L/100 km, specialist servicing rates, and insurance, are significant).

The ideal use pattern is regular weekend drives, club events, and the occasional longer trip, with a modern car handling the daily commute. A 993 that is driven fortnightly stays healthier than one that sits for months.

What does a 993 feel like to drive?

The defining sensation is connection. The steering communicates every texture in the road surface through your palms. The throttle is a cable, direct and immediate. The gearbox has a precise, mechanical engagement that no modern dual-clutch can replicate. The engine sits behind you, and its character changes with every thousand revs, from a gravelly idle through a purposeful midrange to a soaring howl above 5,000 rpm.

The handling, thanks to the multilink rear suspension, is more balanced and forgiving than any previous air-cooled 911. The rear end is stable and predictable under normal driving. Push harder and the car’s rear-engine weight bias becomes apparent, the rear tyres carry the load, the front end is light and responsive, and the car pivots around a point somewhere behind the driver’s seat. It is a unique sensation that no front-engine or mid-engine car replicates.

Compared to a modern 911, the 993 is noisier, less powerful, less grippy, and slower in objective terms. But it is more involving, more communicative, and more rewarding. Modern 911s do the driving for you. The 993 requires you to do the driving, and it rewards you for doing it well.

How much does it cost to service a 993?

Annual service (oil change, filter, inspection): $1,200-2,500 at a Porsche specialist. Major service (every 30,000 km, including valve adjustment and comprehensive inspection): $3,500-6,000. Specialist labour rates in Australia are typically $160-230/hour for a reputable Porsche workshop.

Budget an additional $5,000-10,000/year for unexpected repairs and maintenance items. Something will always need attention on a car of this age. The key is to address items proactively rather than waiting for them to fail, preventive maintenance is always cheaper than repair.

Will 993 values keep rising?

Nobody can predict the market with certainty, but the fundamentals are strong. The 993’s status as the last air-cooled 911 is permanent and unchangeable. The supply is fixed (approximately 68,000 were built, and that number only decreases as cars are wrecked or deteriorate). Demand from collectors and enthusiasts continues to grow as the car’s significance is increasingly recognised.

That said, the rate of appreciation has slowed from the steep climb of 2012-2018. The market has matured, and buyers are more discerning about condition, provenance, and service history. The best cars continue to appreciate; rough or poorly documented cars may plateau or even soften.

The honest answer is: buy a 993 because you want to own and drive one. If it appreciates, that is a bonus. Do not buy a 993 as a pure financial investment, the carrying costs (insurance, maintenance, storage) are significant, and tying up $200,000+ in a car involves opportunity cost.

Maintenance

How do I check for Nikasil bore wear?

Three tests, performed in order of increasing detail:

1. Compression test: A standard compression test measures the pressure each cylinder generates during cranking. All six cylinders should read within 5-10% of each other, and all should be above 120 psi. Uneven readings or low readings on one or more cylinders indicate potential bore issues.

2. Leak-down test: More diagnostic than a compression test. A leak-down test pressurises each cylinder with compressed air and measures how quickly the pressure leaks away. A healthy cylinder will hold 90-95% of the applied pressure. Significant leakage past the rings (audible as air escaping through the oil filler cap) indicates bore wear.

3. Bore scope inspection: A miniature camera is inserted through the spark plug hole into each cylinder. The inspector can visually examine the bore surface for scoring, pitting, or coating deterioration. This is the definitive test for Nikasil bore condition.

Any reputable Porsche specialist can perform all three tests. Budget $300-600 for the complete assessment.

What oil should I use?

A quality synthetic oil meeting Porsche A40 specification. The most commonly recommended oils are Mobil 1 0W-40 and Castrol Edge 5W-40. The engine holds approximately 11.5 litres with filter change.

Change the oil every 5,000-10,000 km or annually, whichever comes first. The air-cooled flat-six uses its oil for both lubrication and a significant portion of its cooling, so oil condition is critical. If you drive the car hard or in hot conditions, lean toward the shorter change interval.

Do not use “energy-saving” or low-viscosity oils (0W-20, 5W-20). These do not provide adequate protection for the M64 engine’s bearing clearances and oil-fed cooling requirements.

How often should the valve clearance be adjusted?

Porsche specifies valve clearance adjustment every 20,000-30,000 km. The air-cooled flat-six’s aluminium cylinder heads expand and contract with temperature, causing clearances to drift over time. Tight valves run hot and burn. Loose valves are noisy but less damaging.

Valve adjustment on the 993 is a specialist job that takes 3-4 hours and costs $600-1,200. It requires removing the valve covers, measuring each of the twelve valve clearances (two per cylinder, intake and exhaust), and shimming as necessary.

What fuel should I use?

98 RON premium unleaded. The M64 engine’s compression ratio (11.3:1 on VarioRam cars) requires high-octane fuel. Lower-octane fuel will cause detonation (pinging), which increases thermal stress on the cylinder heads and can lead to head cracking over time. The cost difference between 95 and 98 RON is trivial relative to the cost of cylinder head repairs.

Technical

What is VarioRam, and does my car have it?

VarioRam is Porsche’s variable-length intake manifold system, fitted to 993 Carrera models from 1996 onwards. It uses vacuum-operated actuators to switch between long intake runners (for low-RPM torque) and short intake runners (for high-RPM power). The system also includes a resonance flap in the intake plenum.

VarioRam cars produce 285 hp compared to the pre-VarioRam car’s 272 hp, with a broader torque curve. The easiest way to confirm if your car has VarioRam is to check the model year (1996+ Carreras have it) or look at the intake manifold, the VarioRam system has visible vacuum actuators on the intake runners.

What is the difference between the 993 and the 964?

The 993 (1994-1998) replaced the 964 (1989-1994), and the two cars share the same M64 engine family and basic rear-engine, flat-six architecture. The key differences:

• Rear suspension: The 993 has a completely new multilink (LSA) rear suspension. The 964 uses semi-trailing arms. The 993’s handling is dramatically more predictable and forgiving.
• Body: The 993 has smoother, more integrated bodywork with body-coloured bumpers. The 964 has visible bumper seams and a more angular appearance.
• Engine: Both use the M64 3.6-litre flat-six. The 993 adds VarioRam (from 1996), boosting power from 250 hp (964) to 285 hp.
• Refinement: The 993 is quieter, smoother, and more civilised. The 964 is rawer and more visceral.
• AWD system: The 993’s Carrera 4 uses a simpler, lighter viscous-coupling AWD system. The 964 C4 has a heavier, more complex system.
• Turbo: The 993 Turbo is twin-turbo (408 hp). The 964 Turbo is single-turbo (320 hp or 360 hp for the 3.6).

The 964 is the more affordable air-cooled 911 and offers a rawer, more elemental experience. The 993 is more refined, better handling, and significantly more expensive.

Is the 993 the same as the 911 (Type 993)?

Yes. “993” is the internal Porsche type number for the 911 produced from 1994 to 1998. Porsche marketed the car as the “911 Carrera,” “911 Turbo,” etc. Enthusiasts and the market use “993” to distinguish it from other 911 generations. Similarly, the preceding generation is the “964” (1989-1994), and the succeeding generation is the “996” (1998-2005).

What is the engine code for my 993?

• Carrera (pre-VarioRam): M64/05 (RWD) or M64/06 (AWD)
• Carrera (VarioRam, 1996+): M64/21 (RWD) or M64/22 (AWD)
• Turbo: M64/60
• Turbo S: M64/60S
• GT2: M64/81R

The engine code is stamped on the engine case and is recorded on the Porsche Certificate of Authenticity.

Can I fit a short-shift kit?

Yes. The six-speed G50 manual gearbox responds well to a short-shift kit, which reduces the throw distance of the gear lever. Popular options include the Wevo short-shift adapter and similar aftermarket products. These are bolt-on modifications that do not require gearbox disassembly and cost $300-600 fitted. The improvement in shift feel is significant and widely recommended.