Buyers Guide Porsche 944 Turbo
Is it true? Can you really buy a turbocharged Porsche for less than the cost of a Nissan Juke? In this guide, we arm you with information you'll find useful when on the lookout for a 944 Turbo… Words Dan Furr, Shane O'Donoghue. Photography Dan Sherwood.
BUYING GUIDE: 944 TURBO
Bag yourself a turbocharged transaxle.
The world of sports cars from Porsche's transaxle family of products is a curious one, populated by vehicles ranging from complete basket cases to concours condition award winners. Of course, you could say the same about air-cooled 911s, but even the tattiest SC, Carrera 3.2 or 964 is going to set you back more than a mint-condition, same-age 944 Turbo.
The old adage buy the best you can afford applies whatever Porsche you're thinking about acquiring, but where most classic 911 owners are unlikely to get their hands dirty, the 944 Turbo's conventional layout (engine at the front) and relatively easy access to the model's vital organs make it much more of an inviting prospect for a home mechanic. Add the lower cost of servicing, repair and general maintenance when compared to ownership of a same-age 911, and it quickly becomes apparent how a 944 Turbo in need of a little work can be a safe place to park your cash. And you thought seeing your name on the logbook of a Porsche wearing a Turbo badge was out of reach when working with a modest budget?!
Having said all this, in recent years, the 944 Turbo has found a new following among a generation of owners who hold the model in high regard. Rightly so, but increased demand means bargain 944 Turbos are becoming increasingly hard to come by. On a positive note, increased value means owners are spending decent money on the upkeep of their cars, but if you're pondering whether now is the time to buy a 944 Turbo, our advice is to do so before it's too late.
SERVICE HISTORY AND MILEAGE
Manufactured between 1985 and 1991, the 944 Turbo is a wonderful modern classic many consider the best of Porsche's transaxle line-up. The turbocharged M44 engine is a peach of a powerplant capable of withstanding a huge amount of abuse and covering big distances (the 944 Turbo's bodywork is likely to fail before the engine), but this doesn't mean you should be complacent — only now is the Turbo commanding high purchase prices after many years spent fighting off the standard 944's reputation as the 'poor man's Porsche'. In other words, when pawing through documentation accompanying the 944 Turbo catching your eye, remember these three words: maintenance is everything.
This is because, much like the 964, many owners didn't spend money on essential servicing and restorative work when these cars weren't worth what they are today. Consequently, though most 944 Turbos will have had any associated faults corrected in recent years, there are many surviving examples out there which will have suffered neglect. Additionally, the model's fabulous handling and brilliant performance — coupled with the historically relatively low cost of ownership — means the model makes for a superb track car. Even Porsche put the 944 Turbo to work, championing the model in its first one-make series, the 944 Turbo Cup. In other words, make sure you carry out a thorough inspection of whichever 944 Turbo you're thinking about buying. The car might look good, but this doesn't mean it isn't carrying damage.
On the plus side, parts for the 944 Turbo are widely available, either direct from Porsche or from many aftermarket retailers, including Design 911, FVD Brombacher, Rose Passion, Porsche Parts UK (formerly Woolie's Workshop, selling both new and used 944 spares), Suncoast Porsche Parts and Heritage Parts Centre. Some Turbo-specific items can be expensive, such as the turbocharger's dedicated water pump, but on the whole, you can run a 944 Turbo comfortably on a modest budget. Keep on top of regular oil changes and timing belt service intervals and you'll have a Porsche perfectly happy to be used in all driving conditions every day.
Don't let high mileage put you off. This is a great bargaining chip and, providing regular servicing has been observed, the 944 Turbo's engine is largely bulletproof.
BODYWORK
Rust is the biggest problem you'll face with a 944. These cars earned a reputation for early onset corrosion, but with the 944 Turbo now becoming collectible, many will have had any corrective work taken care of. There are, however, common areas of complaint you can check. Sills are the worst offenders. Have a good poke around and ask the seller if the inner sills have been replaced. Almost all 944s will have required this work, Turbo or otherwise. Replacement parts (both inner and outer sills) are readily available at relatively low cost, but factor the price of remedial work, plus the inconvenience of having the job carried out, into the price you're prepared to pay for the car you're inspecting.
Look around the wheel arches, at the base of the doors, the bottom of the wings and around the bulkhead. Crawl underneath the car and take a look at the floor. Check around the boot lock and the rear registration plate lights. Also take a look around the sunroof. The rubber seals are prone to failure through decades of exposure to the elements, causing leaks. Fortunately, replacement seals can be bought at low cost.
Early 944 Turbos feature an oh-so-1980s integrated black rear spoiler. Later models replaced this with a colour-coded 'bridge' aerofoil (as seen on these pages). Other differences included the option of staggered Fuchs five-leaf alloy wheels or staggered sixteen-inch 'teledials' (the latter now highly sought after and replacing standard fifteens) on early cars, while later 944 Turbos feature Design 90 wheels, shared with the 964. The Turbo S was available with staggered sixteen-inch Fuchs 'flatdished' wheels similar in appearance to the Design 90.
M44 TURBO ENGINE: PART I
Looking back, it seems inevitable the 944 Turbo would come into being, but turbocharging was still relatively new to the automotive world when the Turbo came to market in 1985, just three years after 944 model launch. Porsche was, however, at the forefront of automotive turbocharging development, having already proven the technology's usefulness in its earlier race and road cars. The latter story started with the 930, a suitably exotic range-topper for the 911 line-up. Turbocharging quickly trickled down to the 944’s predecessor, the 924. The 924 Turbo and 924 Carrera GT homologation special lead to moderate motorsport success, but also helped establish the genre in the road car marketplace, which is why Porsche was confident its development of a turbocharged version of the 2.5-litre M44 engine would reap reward.
Given the market success of the 924 Turbo, it was clear to see how the model's successor would take a sizeable portion of 944 sales. With this in mind, Porsche set out to create a car which could be sold with the same level of performance in all territories. For this reason, a catalytic converter was part and parcel of the engine package from day one. Likewise, a relatively low compression ratio (the ratio between the volume of the cylinder when the piston is at the bottom and when it is at the top) of 8.0:1 was used, which allowed not only for the higher cylinder pressures commensurate with turbocharging, but also the use of lower-octane fuel in markets where high-quality petrol was in short supply. For comparison purposes, the compression ratio for the naturally-aspirated M44 engine was up to 10.9:1.
Indicating how serious Porsche was about the 944 Turbo’s engine, it was loaded with an intercooler from the off, something not fitted to the 924 Turbo (but was a feature of the 924 Carrera GT). It was an air-to-air item, taking ambient air through the slot in the front bumper above the number plate, on through the heat exchanger and reducing intake air temperature after it was compressed by the turbo. Obviously, the system works best at higher speeds, when the throughput of cooling air is faster. The advantages were twofold. First, cooler intake air (to the cylinders) is denser, which means it can burn more fuel to produce more torque at any given engine speed, resulting in increased power output. Secondly, cooler intake air eases the knock limit. Knock, also known as detonation or pinking, occurs when the fuel-air mixture in a combustion chamber ignites in a different location to the flame front started by spark plug ignition. This can lead to catastrophic damage to the piston crown and other components, and is a major challenge for turbocharged cars in particular.
This is because the intake air is hotter and at a higher pressure, which, when mixed with fuel, makes it more likely to ignite. Reducing the compression ratio of the engine helps stave off knock, but this also reduces volumetric efficiency and increases turbo lag. A balance needs to be found. Retarding ignition timing also helps reduce knock, but affects performance. It’s also worth reiterating how the higher the fuel's octane rating, the more compression it can withstand before detonation.
The use of an intercooler cools the intake air — less of a compromise needs to be made elsewhere in the operation of the engine, enhancing reliability as well as outright performance. Further measures were taken to maximise performance regardless of the quality/octane rating of fuel in the tank. Porsche worked with Bosch, for example, to upgrade the latter's Motronic engine control unit to suit the 944 Turbo’s requirements. It was based on the Carrera 3.2 ECU, but to optimise control, a second computer was added, referred to as ‘KLR’. Not only did this unit take a signal from a knock sensor in the cylinder block — retarding ignition if necessary, overriding the main computer — but it could also operate the wastegate for the same reason, making for a robust setup.
Mechanically, the turbocharged version of the M44 engine was remarkably similar to its naturally aspirated sibling. The same 100mm bore and 78.9mm stroke were used, though the pistons were new forged items, with a reprofiled crown featuring a large oblong indent to bring compression ratio down. Thicker cylinder walls were employed to increase strength of the block and give more meat on the metal for the cylinder head gasket to seal to. A larger clutch was fitted to deal with the increased torque. At the top end of the engine, more significant redevelopment was required to cope with the higher temperatures. The turbocharged unit used the original 2.5-litre’s single overhead camshaft design with one exhaust valve and one inlet valve per cylinder. Though the valves were of the same size as those in the naturally-aspirated engine, they were of different construction, using higher-grade steel, while the exhaust valves were filled with sodium to assist with heat transfer away from the head of the valves. The valve seats and guides were also new, and stronger valve springs were required to deal with the increased pressures.
A subtle innovation was found in the exhaust ports, where Porsche initially struggled to deal with heat transfer from the exhaust side of the cylinder head into the engine’s coolant. A ceramic aluminium titanate liner was cast into the exhaust port, keeping the heat within by insulating the alloy of the cylinder head from hot exhaust gases. This meant less wasted heat to the coolant, but also more heat to the catalytic converter, which would have been especially useful during the warm-up phase of the engine — the catalyst has an optimum operating temperature and, until it is reached, allows a greater volume of emissions At this point, it's worth us describing the exhaust piping. It’s hugely different to that of the non-turbo 944. Double-walled steel pipes were used in the fabrication of the two separate exhaust manifolds, where cylinders one and four were paired and cylinders two and three were paired before merging into a single pipe running under the flywheel to the ‘cold’ side of the engine, where the turbocharger was mounted. The wastegate was mounted to a junction in this pipe, relieving pressure via a separate exhaust tube running parallel to the main one and joining it downstream of the catalytic converter.
Porsche located the turbocharger under the inlet manifold in a bid to keep the turbo and its lubricating oil cool. Experience had already shown overheating of oil in the turbo would lead to failure of its bearing, and how oil temperature could increase when the engine was turned off and lubricant wasn’t being circulated around it. Though the M44’s oil pump was enlarged to supply a higher flow rate to the turbocharger, the solution to the problem was introduction of a water-cooled turbocharger.
When the engine is running, coolant flows through the bearing housing of the turbocharger, drawn by the engine’s water pump, but when the engine is switched off, an electric turbocharger cooling pump kicks in for twenty-five seconds. This happens irrespective of water temperature exiting the turbo. If temperature is above a certain threshold, however, the electric cooling pump continues to circulate coolant from the expansion tank, through the turbocharger and back to the expansion tank.
Various aspects of the 944 Turbo were proven at a daylong race held at the Nelson Ledges Road Course in Ohio. The event was designed for production sports cars — the 924 and 944 were previous winners. Porsche gave race veterans, Fred Baker (dealer principal of Fred Baker Porsche Audi in Ohio), Jim Busby and Rick Knoop, two pre-production examples of the 944 Turbo with which to compete. The trio dominated, winning by a massive eighty-four-mile margin. The 944 Turbo was effectively signed off for production.
In 1985, the 944 Turbo launched, offering 217bhp at 5,800rpm and 243lb-ft torque at 3,500rpm, a substantial improvement over 161bhp and 151lb-ft for the standard 944 without a catalytic converter, or 147bhp and 144lb-ft torque with. The zero to 62mph time dropped from a best of 8.4 seconds to just 6.3 seconds, despite a hefty weight penalty. Little wonder the 944 Turbo became so popular.
PORSCHE LOCATED THE TURBO UNDER THE INLET MANIFOLD IN A BID TO KEEP THE TURBO AND ITS LUBRICATING OIL COOL
M44 TURBO ENGINE: PART II
There was only one major upgrade to the turbocharged M44 engine in its lifecycle — in 1988, the 944 Turbo was available with a 247bhp powerplant. Much of the engine remained unchanged from the earlier Turbo, with the increase in output coming from a revised turbocharger and reprogramming of boost control. Peak power was produced at 6,000rpm (200rpm higher than before), while torque of 258lb-ft maxed out at 4,000rpm. Initially, this engine was introduced for the 944 Turbo S in a production run limited to just 1,000 units. The more powerful set-up became standard for the 944 Turbo the following year, lasting until discontinuation of the model. It's what's fitted to the Baltic Blue beauty on these pages.
There’s a little more to the story around this uprated M44 turbo engine. It was effectively the same turbocharged inline-four found beneath the bonnet of racers in Porsche’s first one-make racing series, the 944 Turbo Cup. This kicked off in 1986 and was phenomenally successful, setting the blueprint for today's Carrera Cup competitions. Though power output of the race cars was the same as that of the production 944 Turbo, Porsche experimented with weight-reducing materials for circuit action, including magnesium for the finned oil sump, intake manifold and wheels. The Cup car's Bosch Motronic engine control unit was sealed to protect it from tampering.
In 1987, 944 Turbo Cup cars received a modified KKK turbocharger and a remap to 247bhp. This, then, is the same engine as was brought to production in the 944 Turbo S. The Turbo Cup series ran for four seasons, but it wasn’t the only track outing for the 944 Turbo. There was a real ‘what could have been’ moment in the USA thanks to Al Holbert and his team, Holbert Racing. Holbert’s storied career includes studying engineering and working for IROC founder, Roger Penske, before becoming a professional racing driver. Holbert developed a close link with Porsche and came to run Porsche North America's motorsports division. He saw potential for the 944 Turbo to race in the USA within the Sports Car Club of America (SCCA)'s sanctioned Trans-Am Series. Porsche didn’t offer factory support, which is why Holbert’s team developed its own silhouette racer looking vaguely like the 944 Turbo. It was actually a fibreglass body with a square-tube spaceframe underneath. Holbert’s contacts and experience with Porsche components encouraged the use of 962 suspension and brake components, as well as a 928 torque tube. The engine, meanwhile, was a heavily modified M44 turbo.
Initially developed by McLaren Engines in the US (now McLaren Performance Technologies, Inc.), the Holbert M44 was refined by ANDIAL, the renowned Porsche race car preparation outfit founded by Arnold Wagner, Dieter Inzenhofer and Alwin Springer, former coworkers at a Porsche dealership. The engine used a water-to-air intercooler and had power between 550bhp and 600bhp at its disposal. The car was very fast, but for reasons unconnected to the engine, never achieved its full potential. As a sidenote to this story, ANDIAL produced a 2.8-litre upgrade for owners of the roadgoing 944 Turbo. There were various stages of output available, with significant numbers of components changed. The engine’s crankshaft was swapped with that of the 944 S2 for a longer stroke, necessitated by a change of the connecting rods. Custom Mahle pistons were also included, as was a bigger turbocharger, a unique ECU map and dozens of new ancillaries.
Reports of more than 400bhp in tuned versions of the 944 Turbo engine are not uncommon, and general consensus is the chassis is capable of such outputs without ruining the personality of the host Porsche.
BRAKES, SUSPENSION AND DIFFERENTIAL
The 944's superb near equal front/back weight distribution makes it a brilliant handling sports car, providing even the most inexperienced driver with confidence through chassis predictability. There is, however, always room for improvement, which is why many buyers optioned a limited-slip differential (LSD) and/or the MO30 performance package when these cars were new.
MO30 was standard equipment on the 944 Turbo S — adjustable Koni dampers, progressive rate coil springs, thicker anti-roll bars, stiffer bushes, chassis strengthening plates and height adjustable strut collars formed part of the package. In 1989, the S-badge was ditched and Turbo S comfort equipment became standard for the remaining two years of 944 Turbo production, though MO30 suspension and limited-slip differential remained cost options.
Today, a wide range of suspension enhancements are available for the 944 Turbo. Adjustable coilovers are a common upgrade — offering bump and rebound alteration, as well as configurable ride height —as are polyurethane bushes, delivering a more compliant ride and providing a true 'fit and forget' solution to the deterioration of rubber bushes, caused by age and general use. 944 Turbo brakes are very good, ported over from the 911 Turbo. The Turbo S inherited the 928 S4's four-piston Brembos at the front, though we recommend using high-performance discs, pads and brake fluid, regardless of model and irrespective of whether you're thinking about taking your 944 Turbo to a track.
The factory LSD makes a positive difference to the car's chassis dynamics, but don't fret if the original owner didn't tick this box on the dealership options list — Quaife manufactures a helical LSD specifically for the 944 Turbo. Unlike a conventional plate-style limited-slip differential, the Quaife ATB unit relies on gears rather than clutch plates, resulting in smoother operation. Proven in circuit and drag racing, it automatically biases torque away from the spinning wheel across the axle (to a constantly varying degree) and never locks.
CONFIRMING IDENTITY
We've said it many times before, but the easiest way to verify the identity of the car you're looking at is to check its Vehicle Identification Number (VIN). A 944's VIN is stamped into the bulkhead. Make sure it matches what’s printed on the V5. Elsewhere on the same document, you’ll see the car’s engine number. Make sure it checks out with what's stamped on the block. Early 944 Turbos carry engine code M44/51, while the 944 Turbo S and later 944 Turbos carry code M44/52.
Spend a tenner at mycarcheck.com, where you can download a history report outlining any insurance claims, change of registration number, recorded mileage and whether there is any outstanding finance on the Porsche you're looking at. You should also enter the vehicle’s details into the DVLA’s online MOT database (visit bit.ly/dvlamot), a free service which will return all passes, failures and advisories registered as far back as records are stored. You will also be able to see the mileage of the car at the point of each test. Compare this with what the odometer currently displays. Make sure nothing is amiss. Additionally, take advantage of the Suncoast Porsche Parts VIN decoder (check it out at bit.ly/suncoastvin), which will provide you with a Porsche-specific build sheet in exchange for just $10. This document will let you know exactly how the car left the factory, including model specification and any Individual Equipment items optioned. We've lost track of the number of Porsche owners who have discovered their car makes use of a special feature they only found out about after ordering this report, though your local Porsche Centre or the car's original dealer may be able to furnish you with the same information without charge. It's worth noting Porsche record-keeping is much better today than it was when the 944 Turbo was new. With this in mind, pop the carpet on the inside of the boot lid and you'll find a factory sticker listing a series of codes relating to everything from originally optioned equipment to paint finish.
OWNER OPINION
Following time in charge of a 964 Carrera 4 and a 944 S2, Mark Wibberley, founder of car care product specialist, More Than Polish, bought his late 944 Turbo in 2003. Despite now having covered 186k miles, the turbocharged transaxle runs faultlessly, bolstering claims even force-fed variants of the M44 engine will deliver rock-solid reliability if maintained correctly. «It pulls like a train,» Mark tells us. «I bought the car at 100,030 miles and used it every day for many years, including for family road trips all over Europe, as well as for carting exhibition stands to shows across the UK. The amount of luggage you can carry in the back of a 944 is extraordinary, making it a truly practical Porsche, which isn't something I could say about my 964.»
We wonder how he ranks 944 Turbo performance against seat time in the 944 S2. «I always felt the S2 could be faster, despite its three-litre engine. The Turbo, on the other hand, feels powerful as soon as the turbocharger kicks in. The car gives you a burst of rapid acceleration, which you can hold as you progress through the rev range, and which is ideal when pulling out to overtake traffic. With the S2, I often wondered if I was going to get past as quickly as I hoped when beginning the move! That said, the S2 is more on par with the early 944 Turbo than the higher-output Turbo S or my late-model Turbo.»
We ask what he recommends prospective buyers look out for when on the hunt for a 944 Turbo to call their own. «The build quality of these cars is absolutely phenomenal. Other than general wear and tear, you shouldn't have much to worry about, though it's important to note most cars of this age will have been treated to corrective paintwork at some point in their lives. Check for accident damage and inspect the sills.»
Preparing his Porsche for sale, he's been reminded of some of the more expensive model-specific components, such as the air box (which he has just replaced), but tells us the cost of 944 Turbo ownership is significantly less than being in charge of a same-age 911. He also loves how communicative the chassis is. «Unlike the 911, you know exactly when a 944 Turbo's rear end will break away, allowing you to control the power into and out of bends with a far greater degree of confidence. You can still provoke the car, of course, but handling is far superior to the 911, making the 944 Turbo a much more usable Porsche for the majority of drivers. The 944 Turbo is also a much more comfortable car, with a beautifully designed dashboard, controls where you expect them to be and generous cabin space, even for tall people like me. Put it this way, I'm six-foot-three and I don't ever feel cramped or fatigued after driving the car for hours on end.» Proving the point, Mark travelled the near six-hundred miles from Brittany in France to More Than Polish's headquarters in Stamford, Lincolnshire, in a single stretch. «The 944 Turbo is such a versatile car,» he says. «A grand tourer when you want it to be, and a proper sports car when you put your foot down and the turbocharger kicks in. The car also feels fairly modern, making it good for commuting in today's traffic.» If you fancy buying this brilliant 'go anywhere, do anything' Porsche, drop Mark a line via the contact page at morethanpolish.com.