'86 vs '87+ turbo...?
01-06-2015, 10:04 AM
#1
Rennlist Member
Thread Starter
'86 vs '87+ turbo...?
Is there any significant difference (improvement, changes, etc) for a 1987 or later turbo vs a 1986 Turbo? (I'm aware of the airbag addition, and I've heard something about the offset being changed???). Thanks in advance for the info.
01-06-2015, 10:12 AM
#2
Nordschleife Master
The below is from this link: 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.
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.
01-06-2015, 10:17 AM
#3
Yes, there are quite a few. Best to check the technical bulletins : http://bethnrayndogs.com/car_docs/Po...ech_Bulletins/
Scroll a little down and you will see the 1987.pdf, 1988.pdf, 1989.pdf, and so on - this is the full book. You'll see differences such as bulletin 8711 (among many others) which had new exhaust manifolds and x-pipe. I think there is some difficulty swapping out wastegates on the 1986 models that is different than the rest (perhaps has to do with the aforementioned exhaust changes). I believe you will also find stuff such as different oil cooler seals, OPRV, and who knows what else. Anyway, hope this helps.
Scroll a little down and you will see the 1987.pdf, 1988.pdf, 1989.pdf, and so on - this is the full book. You'll see differences such as bulletin 8711 (among many others) which had new exhaust manifolds and x-pipe. I think there is some difficulty swapping out wastegates on the 1986 models that is different than the rest (perhaps has to do with the aforementioned exhaust changes). I believe you will also find stuff such as different oil cooler seals, OPRV, and who knows what else. Anyway, hope this helps.
01-06-2015, 11:19 AM
#4
Rennlist Member
I've always preferred the non-ABS and early offset wheels on the 86 models over the 87+ models personally. But if you live in a rainy or snowy climate then ABS would be helpful in certain circumstances.
01-07-2015, 10:06 AM
#5
Rennlist Member
Raleigh your comment is not 100% true. As with my 1986 built in march. The crossover is two piece as with the later cars. The only difference being the flange is a little different. The early 1986 cars had the single piece crossover that have some difficulties with changing the waste gates. Just an FYI.
I certainly would not pay a premium for a later car, unless it is a low mileage s. I prefer the 1986 for a lot of different reasons.
I certainly would not pay a premium for a later car, unless it is a low mileage s. I prefer the 1986 for a lot of different reasons.