lart951

http://www.jmgporsche.co.uk/index.ph...44turbopartone



The different Porsche 944 Turbo engines and the cars they were installed in.

Tuning the Porsche 944 Turbo is something that we at JMG Porsche have been doing extensively for many years. We redesigned the standard 2.5 Litre engine in 2005 to provide the worlds first 3.2 944 Turbo engines as well as building the very best 2.5, 2.8 and 3.0 engines for 944 Turbos. We have even tuned standard engines with over 100,000 miles on the clock to have over 400 horsepower reliably. So you could say we know what we are talking about.

In this series of articles, I plan on showing you what can be done with a 944 Turbo to improve its performance, you will learn what the limits are to the original components and what can be done to improve those components.

So first things first, we need to cover the basic engines installed into the 944 Turbo and the turbo chargers the factory connected to them.

The Engines.

Porsche officially launched three revisions of 944 Turbo engine. The M44.50, the M44.51 and the M44.52.

M44.50

In 1985 when Porsche released the 944 Turbo, the original engine was an M44.50. With a capacity of 2.5 Litres, this engine was designed to be the test bed that the first customers of the 944 Turbo would be unwittingly testing for Porsche along with long term Porsche test cars, some fitted with a M44.50 engine as fitted to the production cars, others fitted with a M44.51 and some fitted with a M44.52. As Porsche were a low volume car manufacturer, this allowed Porsche to trim the production costs of the engines over time, as their test cars mileages rose higher without issues and the customers cars were monitored.

This original version of the engine, the M44.50 featured the following:-
Sodium filled exhaust valves
Ceramic coated exhaust ports
Modified engine block
Thicker engine casting with higher density aluminium engine block
Forged piston connecting rods
Manual Cam belt tensioner
K26/6 Turbo (Size 26 compressor matched with a size 6 exhaust turbine.)

This engine produced 220 bhp @ 6000 rpm and 243 ft-lb @ 3500 rpm, and was almost completely bullet proof. If anything Porsche knew it was capable of much higher performance, but due to the superior weight distribution of the 944 design, more performance would have made it faster than the companies flagship 911 Turbo on the road or track. Arguabley the 944 Turbo is faster on the bends and is certainly no slouch on the straights, so it was decided to limit power to 220 bhp.

M44.51

Half way through 1986 the 944 turbo received the M44.51 engine which had now seen another year of testing in the factory road test cars, so it was put into production as the new engine for the 944 turbo. Much the same as the M44.50, but with the following differences.

Thickness and density of the engine block reduced back to the same as a 944 non turbo to reduce production costs
Cast piston con rods instead of the expensive forged con rods of the M44.50

For normal or tuning use, there is no difference between the M44.51 and the earlier M44.50 except these components were downgraded in the later 51 engine. However, for the engine builder wanting the best from factory components, a M44.50 block and M44.50 con rods are sought after.

The M44.51 engine still featured the same K26/6 turbocharger and provided the same power output of 220 bhp and 243 ft-lb torque.

M44.52

During 1987, Porsche had finished testing with a new upgrade for the engine, an automatic cam belt tensioner, wider balance shaft belt (most earlier engines were upgraded during service belt replacements) and a deflector rail on the waterpump. Other than this, the engines are identical. This version of the engine continued until the Porsche 944 Turbo stopped production at the end of 1991 and the begining of 1992.

It is said that the M44.52 engine is one that produces 250 bhp, this is not true, but we will cover that in a moment.

The cars.

The early cars before 1987 featured a different wheel offset to the later ones, something that changed with all Porsche models in that year, this was done to improve handling and road safety, although it is also said that these earlier cars are more edgy and track focused, partly due to the lack of option for anti lock brakes (ABS) and a limited slip differential, but also due to the geometry caused by the wheel offset, but thats for another article.

After 1987 the engine changed to the M44.51 engine, performance was unchanged, the wheels changed to the later offset and some extra options became available such as ABS.

In 1988 Porsche had been racing a more powerful and upgraded 944, the 944 Turbo cup for a little while and decided to make a special edition 944 Turbo, the 944 Turbo S. This featured the sports MO30 Suspension and brakes, a larger turbocharger, the K26/8 (Larger exhaust turbine and housing) and a limited slip differential (LSD) all lifted directly from the 944 Turbo Cup race cars. The Turbo S featured 250 bhp @ 6000 rpm and 258 ft-lb of torque, an impressive increase in power, but with slightly more lag than the 220 bhp versions with the smaller turbo. These cars were fitted with the same M44.51 engines that all 944 Turbos had for the previous year and the non turbo S cars of 1988.

The turbo S version of the car was sold as a limited edition, at a price premium. Much to the annoyance of Turbo S owners, the following year in 1989 Porsche upgraded the standard Porsche 944 Turbo so that all 944 Turbo's featured the same K26/8 Turbocharger, and so produced the same power output as a Turbo S. Although in most international markets, the MO30 suspension, brakes and LSD transmissions were still optional.

Over the years there also were many changes to the 944 Turbo other than what we have mentioned here, but we will cover those in other articles as time goes on. For the moment, we have been interested in the engines, the years and what changed, as well as getting rid of some myths at the same time.

By now, you should have a good understanding of the 944 Turbo and its history, as well as the engine and the differences in the engine types.

In the next installment we will look at the Porsche 944 Turbo, component by component, to assess the tuning limitations of each part...


So much misinformation, 88 Ts fitted with a m44/51 engine block what is this guy smoking,also all the m44/51 in the us had the RARST rods but according to this guy they had the NA cast rods lol. Oh and the m44/52 engine is not the one that produces 250hp oh boy so misguided.

PF

Actually JMG are amongst the best in the business regarding these cars. Many things differ between US and ROW cars, I think better to call Jon and disguss his/their claims.

lart951

If that information is correct then Porsche sold different engines overseas.

333pg333

No expert but pretty sure there were some differences around the world.
Also, this was the shop that made the 3.2lt LiL motor. I don't think they really do a ton of high end custom i4 Porsche motors but have done a few. There's really not a big market for these sort of motors in many countries. The 944 world can't justify the costs in general and the guys with more $pinach tend to gravitate to the rear engine cars.

lart951

The information he offers is practically the contrary of what we have been told and experienced in the US, Even Clark's Garage contradicts his take on 951 engines. Maybe I'm blowing it out of proportion but check clarks Garage

http://www.clarks-garage.com/951faq.htm

3.2 1987 Model Year

There were minor modifications to the 951 engine for the 1987 model year. Most notable is the change from the eccentric roller cam belt tensioner to a spring tensioner arrangement. This change also occurred on the normally aspirated cars. Also, an oil level sending unit was added to the oil pan which illuminates a low oil level light on the dash. The 1987 model cars were provided with a one piece oil pressure relief valve as opposed to three piece unit on the 1986 models. As a result of the addition of the cam belt spring tensioner and changes to the water pump pulley arrangement, a new set of timing covers were produced for the 1987 models.

Beginning in the 1987 model year, the 944 Turbo transaxle came without and external oil cooler as standard equipment. However, the transaxle with cooler as well as the transaxle with limited slip differential and cooler were still available as optional equipment.

In 1987, ABS was offered as optional equipment on both normally aspirated cars as well as turbos. This required the wheel offset to be increased for the 1987 model year from 23.3 mm to 52.3 mm. All cars received the increased offset wheels even if they were not equipped with ABS. Tubular front stabilizers were used on the 1987 model cars (25.5mm x 4 mm).

The M030 suspension option was made available starting in the 1987 model year. With this option the front tubular stabilizer size increased to 26.5 mm x 4mm. Through the end of the 1988 model year, FS black struts were standard equipment on 944 Turbos with Koni yellow struts as optional equipment. With the M030 option, height adjustable Koni yellow struts were added. Also with the M030 option, the strut bearings have a harder rubber compound than earlier models which can be identified by a green stripe on the underside of the bearing. The spring rate for all 944 Turbos not equipped with the M030 option is 21.8 N/mm with an unsprung length of 251 mm (through the end of the '88 MY). The M030 option springs have a rate of 28 N/mm with an unsprung length of 220 mm.

For the rear suspension, all 944 Turbos through the end of the 1988 model year were equipped with FS grey shock absorbers as standard equipment. Koni yellows were available as optional equipment. With the M030 option, the Koni yellow shock absorbers will have two white dots offset by 180°. Also with the M030 option, the torsion bar size was increased to 25.5 mm.

On the interior, the 1987 944 Turbo became the first production car in the world to be equipped with driver and passenger side air bags as standard equipment. On the normally aspirated 944s for that year, the driver's side air bag was standard equipment, but the passenger side air bag was optional. As already mentioned, a low oil level light was added to the dash. Also, a 180 mph speedometer was added as opposed to the 170 mph speedometer on the 1986 model Turbos.

3.3 1988 Model Year

There were no significant changes to the 944 Turbo until the middle of the 1988 model year. One minor change involved changing the chip arrangement in the DME unit. Earlier 944 Turbos (86/87) have a DME with a 24-pin chip. Beginning with the 1988 model year, a DME with a 28-pin chip was installed. It's not exactly clear why this change was made, but it has been rumored that it was in anticipation that more control features were going to be added to later models. At any rate, the 1988 DMEs received the same map as the early cars and I've been told that the extra 4 pins on later DMEs were never used.

In 1988½ Porsche introduced a new 944 Turbo which was designated as a 944 Turbo S. The first example of the 944 Turbo S were a limited production run. Exact numbers on the limited production 951 S cars varies, but seem to be between 750 and 1000. All of the limited production vehicles came with a Silver Rose Metallic exterior and burgundy plaid cloth interior.

The Turbo S received the M 44.52 engine as opposed to the M 44.51 engine of the earlier models. The engine itself remained essentially unchanged from the early 1988 models. However, the turbocharger was changed to a K-26#8. The Turbo S was electronically limited to the same maximum boost (1.75 bar) as the early 944 Turbos. Also both models achieve maximum boost at approximately 3000 rpm. However, the K-26#8 turbocharger was capable of maintaining maximum boost until 5800 rpm while the boost on the early turbos would decrease from 1.75 bar at 3000 rpm to 1.52 bar at 5800 rpm. This resulted in a 30 hp increase in peak horsepower and a 15 ft-lb. Increase in peak torque.

Humboldtgrin

Geez Luis, never seen you so butt hurt over such small stuff. Not like it's an article about shoving an LS engine into a 951.

lart951

Now the LS thingy that's blasphemy, it was just the idea of a supposedly well known Porsche guru spreading misconceptions. You guys know I research my parts like this one

http://www.ebay.com/itm/Porsche-944-...item3af3986773

PF

There are misleading info to be had all over I think and maybe this is wrong I am not to judge. There is a ton of knowledge on this forum and very competent people. However JMG has been around working with these cars since the early stages and in close contact with the factory, so I think there might be something behind these claims. We all know Porsche made all sorts of changes throught the years for different markets and many not even documented in manuals.I have seen for instance a 88TS sold new in Sweden with a M44/52 engine but with the engine number in the same location as the earlier cars/blocks(yes original engine) Maybe that is what JMG is referring to.

I think a contact with JMG is best and maybe that way we can learn something new about these cars we all love (and hate) so much.

lart951

All 86-88(non TS) that I have dissected they all came with m44/51 except a few that had dealer engine block replacement with weird numbers, all the 88-89 TS that I had parted had the m44/52 that's how i was able to sell them more expensive. If you guys in Europe got the m44/51 in the turbo S then you guys got screwed by Porsche, lol. BTW is common knowledge in the US that the engine code for the 250hp engine TS is the M44/52 period. Also all the 86-88(non TS) had the forged RARST rods and all the 88 TS as well except a few of the 89 Turbos that has the weak na cast rods.

PF

I am not debating that info I just think that better to contact JMG and ask why they state the info they do and see if there is any substance to it. That way maybe we learn something new or they need to change what they teach. It is after all a company with very good reputation.

Dave W.

My interpretation is that the article by JMG was written a long time ago before the fine details of these cars was well known. The article may have been the best info at the time, but we've come a long way since then.

lart951

In America we call this a Checkmate: