Porsche 911 930 Turbo Buyer's guide
Buyer's guide for the Porsche 911 930 Turbo.
Notes on variants: Early 3.0 (’75–’77) cars are rarer in the UK and prized for purity; values reflect scarcity, but parts for the unique non‑intercooler layout are costlier. The 1989 five‑speed (G50/50) is the most usable in town and valued accordingly; transmission parts are specific and dear. Factory Exclusive slant‑nose (Flachbau/SE) cars are collectible only with documentation and correct features; many period conversions exist. Tyre choice in 16‑inch sizes remains available but limited; matching quality tyres and recent date codes matter. If you intend regular summer use, invest in a modernised A/C system and a thorough heat‑management service (cooler, shrouds, engine tinware, timing and mixture) to protect the turbo and head studs.
Built from 1975 to 1989, the 930 is the first production 911 Turbo and the car that defined Porsche’s forced‑induction road cars. Early 3.0‑litre cars (’75–’77) made their name with a small KKK turbo and no intercooler. From 1978 the 3.3‑litre with an intercooler, stronger brakes and chassis changes became the mainstay. All but the final model year used a four‑speed transaxle; 1989 cars gained the G50/50 five‑speed and now command a clear premium. In the UK, originality, right‑hand drive, strong maintenance history and corrosion condition dictate value more than mileage alone. The best examples feel stout, with clean boost control, accurate steering and firm, well‑damped ride. Poor ones smell of hot oil, wander on the motorway, and smoke on the overrun.
Facts first. The 930 uses an air‑cooled flat‑six with Bosch K‑Jetronic (CIS) mechanical fuel injection and an external wastegate KKK turbocharger. Power for UK‑market 3.0s was c.260 PS; the 3.3 arrived in 1978 at c.300 PS with a larger turbo and intercooler. UK cars typically have twin fuel pumps and, from later years, a radiator‑type front wing oil cooler with fan. The four‑speed transaxle is extremely strong; the 1989‑only G50/50 five‑speed is rarer and transforms drivability at low speeds. In practice, condition trumps year. A healthy engine starts cleanly hot and cold, idles near‑rock steady once warm, and pulls cleanly from 2,500 rpm with a progressive hit of torque from c.3,500 rpm. A haze on start‑up that clears quickly is typical; sustained blue smoke at idle, on boost or after a long overrun points to valve guides, turbo oil seals or scavenge issues. CIS that is even slightly out can mask deeper problems: air leaks at the intercooler seals, decel valve, or intake boots cause hunting, flat spots and hard starts. The warm‑up regulator, fuel accumulator and metering head are consumables on age alone. Known 930 specifics include later 3.3s on Dilavar lower head studs that can snap; chain tensioners that benefit from the Carrera pressure‑fed upgrade; and heat‑soaked turbos that coke their oil if not idled down. External wastegate diaphragms harden and stick, causing boost spikes. Twin fuel pumps rely on their relays and grounds; lazy pumps show as lean surge under load. The CDI ignition box and coil can intermittently fail when hot. The four‑speed’s synchros are stout but dislike rushed 2nd‑to‑1st selection. A heavy pedal often means a tired cable, omega spring or helper mechanism; judder may be a failing rubber‑centred clutch hub on some cars, which disintegrates with age. ZF limited‑slip diffs wear their plates and get noisy or ineffective. Oil leaks are part of the landscape, but wet timing chain housings, oil return tubes and the rear main seal require attention, and pulled exhaust studs add cost. Costs we actually see: a top‑end refresh with guides, studs and ancillaries typically lands £12k–£20k depending on scope; a full rebuild is £25k–£35k+. Turbocharger overhaul/replacement is usually £1,500–£3,500. A clutch on a four‑speed car is commonly £1,800–£2,500 fitted. Gearbox refreshes run £4k–£7k. A proper CIS recommission with pumps, accumulator, WUR service and lines can be £1,500–£3,000. Budget accordingly.
The 930 body‑in‑white is reinforced over a period 911 and sits on torsion bars with specific anti‑roll bars and Bilstein dampers. Geometry is critical; a car set up by someone who knows 930s will feel tidy and confidence‑inspiring even on B‑roads. Age hardens every rubber component. Expect to replace spring‑plate bushes, trailing‑arm bushes and engine/gearbox mounts to restore tightness. Rear wheel bearings and CV joints are consumables on higher‑mileage cars. Brakes on the 930 are serious kit, with four‑piston aluminium calipers and larger ventilated discs; later cars gained a servo. Calipers corrode between the halves and seize pistons if the car sits. Flexible hoses balloon and lines corrode. A long pedal on the road test often responds to a caliper rebuild, fresh discs/pads and a proper bleed; sponginess that persists may be a failing master cylinder or servo issue. Tyres matter. Correct‑size 16‑inch Fuchs with 205/55 front and 245/45 rear are common; quality tyres in these sizes still exist but choice is narrower than for 17s. Old, hard tyres ruin the ride and feedback. The evidence suggests that a full suspension refresh with geometry is £3k–£5k with quality parts; a full brake overhaul with caliper rebuilds and discs is often £1.2k–£2k.
Corrosion is the 930’s value killer. The wide rear quarters hide the infamous ‘kidney bowls’ (inner sill/quarter reinforcement) which rot from the inside; repairs here are specialist and expensive. Front pan and battery tray corrosion is common, accelerated by acid spills. Screen surrounds and the scuttle rust if the seals have perished; bubbling here often indicates deeper trouble. Check jacking points, inner sills, B‑pillars, rear torsion tube mounts and the base of the A‑pillars. Look hard at the front wings around the headlamp bowls, the bumper mounts, and the rear cross‑member. Sunroof drains block and rot the cassette. Underbody coatings can conceal much; use a borescope. Originality cues matter because 930‑specific panels and trim are dear. Early 3.0 cars have the smaller, non‑intercooler tail; 3.3s carry the ‘tea‑tray’ with intercooler cut‑out. Verify the front valance, fogs and oil‑cooler ducting on later cars. Many have period body kits; some are reversible, many are not. Factory slant‑nose (Flachbau) and Exclusive‑built specials carry a premium only if documented; conversions do not. Panel gaps should be even, with no witness marks along the inner wings and slam panel. Evidence of rear impact—creased inner arches, distorted engine latch panel—should give pause.
The cabin is hard‑wearing but now four to five decades old. Dash tops crack, speaker grilles warp and door pockets sag. Leather shrinks on bolsters; early cars may have Pasha or tartan cloth, which is expensive to retrim correctly. Electric seat mechanisms, window lifts and central locking often need attention; switches and relays are available but the labour adds up. HVAC is weak when perfect; expect upgrades or a proper R134a conversion with a new condenser, evaporator and barrier hoses if you want cold air. Heater control boxes, footwell blowers and flap cables seize when the car sits. Instrument odometer gears strip and are an easy but telling fix; mismatches between MOT history and mileage aren’t rare. A correct 930 should have the boost gauge integrated into the tachometer on later cars and period‑correct VDO instruments with date stamps. Stereo holes and add‑on alarms are value reducers.
Provenance is everything on a 930. We prioritise UK‑supplied, right‑hand‑drive (C16) cars with complete service history and evidence of ongoing use over museum mileage and long storage. Many UK cars are imports from Europe, Japan or the US; none is a problem if documented, but RHD commands a premium here. From 1980–85 the US missed the 930, so some American cars are later re‑imports. Verify matching numbers. Engine and gearbox type and serials should correspond to the service book and Porsche records. Check the under‑bonnet options label and service book stickers against the car’s equipment. Factory slant‑nose/SE or other Exclusive builds must have paperwork; without it they are just modified Turbos. Sensible mechanical updates—Carrera tensioners, improved oil cooling, wastegate refresh, and a sympathetic turbo/intercooler upgrade—don’t hurt value if documented. Crude boost controllers, aftermarket ECUs on CIS cars, and non‑reversible body changes do. Evidence of a top‑end engine refresh, turbo/wastegate overhaul, CIS recommission and a suspension/brake rebuild within the last 10–15k miles carries real weight. Ask who did the work and when. Invoices from recognised Porsche specialists, MOT history continuity, and a thick file of small consumables suggest careful ownership. As for values, UK‑market asking prices in 2024 typically show good RHD 3.3 coupes in the £120k–£160k band, exceptional cars higher; 1989 five‑speeds significantly more; Targa and Cabriolet a step down; LHD 10–15% softer in the UK. Buy on condition and paperwork, not mileage alone.
Start with paperwork. Confirm VIN, engine and gearbox numbers against the logbook and history. Read the file front to back: look for evidence of top‑end work, CIS and turbo/wastegate service, suspension and brake overhauls, and regular oil changes with valve‑clearance adjustments. Cold start from stone cold. It should catch promptly, flare briefly, then settle. Listen for chain rattle (tensioners) and tick (exhaust leaks). Watch the exhaust: a brief puff is fine; sustained blue smoke is not. Check for even idle when warm. Verify that both fuel pumps run (you can often hear the front). With a CO meter, a warm idle around 2.5–3.0% on CIS cars is typical; without, rely on driveability. On the road, build heat gently. Note clutch weight and take‑up; judder points to the hub, slip to wear or oil. Test all gears; 1st should engage cleanly at a near‑stop. Under full load from 3,000 rpm in 3rd, watch the boost needle: it should rise briskly and hold steady without spikes or flutter. Hesitation suggests fueling or air leaks. Any detonation (rattle under load) is a red flag. Lift after boost and check mirrors for smoke. On overrun, blue smoke points to guides or turbo seals. Steering should be accurate with no dead zone. Tramlining and wander point to geometry, bushes or tyres. Find a quiet, straight road, brake progressively from motorway speeds; the car should stop straight with a firm pedal and no vibration. After the drive, check for oil leaks and fuel smells in the left front wing (CIS components) and engine bay. Up on a lift, inspect: front pan and battery tray; inner wings; jacking points and sills; kidney bowls with a borescope; rear torsion tube mounts; screen surrounds and scuttle; sunroof cassette and drains. Look for fresh underseal, overspray, and seam disturbances along the inner wings, front slam panel and rear latch panel. Check CV boots, play in wheel bearings, and brake lines/hoses. Inspect exhaust primaries and heat exchangers for cracks. Confirm the presence of the correct intercooler and tail for the year. Finally, run a compression and leak‑down test (we like <8% leak‑down across the board on a warm engine) and borescope if results vary.
Our view is that the sweet spot for UK buyers is a UK‑supplied, right‑hand‑drive 3.3‑litre coupé from 1986–1988 with the four‑speed. These cars avoid the 1989 premium yet drive with the same character, and parts support is excellent. We would target a car with: a documented top‑end rebuild in the last 20k miles (guides, studs, valve work), recent CIS and wastegate service, refreshed suspension with proper geometry, and a brake overhaul. LSD is desirable. Sympathetic reliability upgrades—Carrera tensioners, radiator‑type oil cooler with fan, renewed fuel pumps/relays—are positives. We would avoid heavy boost mods, irreversible body changes and long‑stored, ultra‑low‑mile cars without recent recommissioning. For budgeting, expect strong RHD coupes in this bracket to be advertised roughly £120k–£160k depending on history, condition and colour/spec, and keep £10k–£15k in reserve for first‑year catch‑up.