959 wiring diagrams?

[nickd]

Big ask, but there have been a few 959 threads here. Are there any pdf versions of the 959 diagrams floating around?

I'm mostly interested in the AWD electronics. Trying to get inside the mind of the engineers and compare to the 964 C4 diagrams.

Thanks!

[mysocal911]

[QUOTE=nickd;11451436]Big ask, but there have been a few 959 threads here. Are there any pdf versions of the 959 diagrams floating around?

I'm mostly interested in the AWD electronics. Trying to get inside the mind of the engineers and compare to the 964 C4 diagrams.

Thanks!

Traction Control (959 168 130 00)?

[nickd]

I believe that's the AWD ecu part number. I'm only looking for the workshop manual wire diagrams, which can be enlightening on their own. I'd love to see info on the ecu, but imagine that's all locked up in a Bosch warehouse inside some long-forgotten file cabinet

[mysocal911]

Originally Posted by nickd

I believe that's the AWD ecu part number. I'm only looking for the workshop manual wire diagrams, which can be enlightening on their own. I'd love to see info on the ecu, but imagine that's all locked up in a Bosch warehouse inside some long-forgotten file cabinet

Not really! Just as some have reversed-engineered Porsche DME ECMs, they most likely reversed-engineered 959 ECUs too.

[FrenchToast]

Originally Posted by nickd

I'm mostly interested in the AWD electronics. Trying to get inside the mind of the engineers and compare to the 964 C4 diagrams.

What info are you trying to find? If you are trying to find out the designed behavior of the 959 PSK AWD system a wiring diagram won't tell you. It will only tell you where current can go, not sensor input values and module operation. Like any modern, computer-driven AWD system it is taking variables from yaw sensor, accelerometer, steering angle, throttle position, boost, wheel speed, etc. and putting them into an algorithm that decides what to do with the differentials.

Even if you did find what you are looking for, the hardware is different between the two cars, so anything you found wouldn't be comparable. Also, the physics of a 964 are quite different from a 959; putting a 959 AWD system in a 964 without thousands of miles of R&D would likely yield a car with handling worse than both cars.

Technical manuals may have very basic outlines of how the system functions but it won't give you a diagram of how the software was coded. As you hypothesized, that is somewhere in Porsche's archive files. Maybe Bosch has a copy, who knows. Neither of them would give you a copy. A major-league Porsche customer VIP couldn't even get that kind of info. You would likely need to be a senior employee with legitimate reason to access that kind of info, i.e. a customer with a blank check wants a new module and there are no spares left. And they'd make you sign a few dozen NDAs.

It would take you thousands of hours and probably thousands of dollars of obsolete hardware to fully reverse-engineer what is in the PSK brain.

It would be easier to take your existing hardware (electric-operated clutch packs as I recall for the 964) and write a program to have the lock-up be adjustable via dials in the cockpit. But you'd need to know what the design limitations of the components are; i.e. you could be requesting full lock for too long and overheat the hydraulic system.

Since you're in MA I would start with a call to EPE in Natick. I think they specialize in 959s. Or try Canepa, maybe they have reverse-engineered some of the computers as part of their 959 powerkits.

[nickd]

There are often unusual circuit designs that are hold-overs from previous models. That's part of what I'm interested in looking at. I'm also curious if the 959 front/rear diff gauge signals come directly from the awd ecu (possibly also available through unused pins on the 964 ecu). And just generally to see how similar or different the in/out is on the ecu.

Things I wasn't really looking for: a part number, the Spanish Inquisition, the multitude of other unrelated feedback

[mysocal911]

Originally Posted by FrenchToast

Technical manuals may have very basic outlines of how the system functions but it won't give you a diagram of how the software was coded. As you hypothesized, that is somewhere in Porsche's archive files. Maybe Bosch has a copy, who knows. Neither of them would give you a copy.[B] A major-league Porsche customer VIP couldn't even get that kind of info. You would likely need to be a senior employee with legitimate reason to access that kind of info, i.e. a customer with a blank check wants a new module and there are no spares left. And they'd make you sign a few dozen NDAs.

You're joking, right?

The TCU (Traction Control Unit) uses '80s processor technology (NSC - National Semiconductor - Z80 8-bit) with an external EPROM with a small EEPROM for fault codes.
Most likely NSC just provided an assembly language compiler, i.e. no C complier, so the TCU source code was written in assembly language.
Given that, the code in the EPROM could be disassembled to determine the TCU's logic functionality. A little time consuming, but doable.
Most all the supporting digital circuitry is RCA/NSC CMOS generic TTL types, e.g. CD4001 quad NOR gate.

The other ECU (OCU) part of the traction control system, can also be reverse engineered too, but a little more difficult given its packaging.

Originally Posted by FrenchToast

It would take you thousands of hours and probably thousands of dollars of obsolete hardware to fully reverse-engineer what is in the PSK brain.

Oh please!

Those two ECUs are relatively easy to reverse compared to a 997 or later Porsche ECU.
As with any reverse engineering effort, it only takes time, perseverance, and of course electronics/system design/programming abilities.

Originally Posted by FrenchToast

It would be easier to take your existing hardware (electric-operated clutch packs as I recall for the 964) and write a program to have the lock-up be adjustable via dials in the cockpit.

That's possible like the green 964 C4 (P. Long) modified (RothSport engine) at the Luftgekuhlt this year.


FrenchToast - A 959 owner from Rennlist, most likely.

[mysocal911]

Originally Posted by nickd

There are often unusual circuit designs that are hold-overs from previous models. That's part of what I'm interested in looking at. I'm also curious if the 959 front/rear diff gauge signals come directly from the awd ecu (possibly also available through unused pins on the 964 ecu). And just generally to see how similar or different the in/out is on the ecu.

Time to buy a 959 shop manual (WKD 482 310) and reading section 39, right?

Originally Posted by nickd

Things I wasn't really looking for: a part number, the Spanish Inquisition, the multitude of other unrelated feedback

Given that view, maybe time better spent on Rennlist!

[nickd]

Sure. I'll just purchase a copy of the expensive, out-of-print, manual for the few pages I'm interested in learning about. While I'm at it, I'll pick up a 959 to examine directly. And somehow I'll involve rennlist in the conspiracy.

Any useful comments out there?

[dw1]

Maybe PM Wayne directly? I recall his 959 postings and he may be able to offer some insight/information.

As one who has been involved in reverse engineering competitive products (specifically medical electronics and firmware/software, e.g. to investigate/evaluate intellectual property issues) I completely agree that this is certainly do-able, especially with Z80, 6800, 88000 or other commonly used 80's tech.

[nickd]

Thanks dw1, I sent a note to Wayne hoping he might have a free minute.

Reverse engineering / disassembling old controllers is a whole other ballgame. A massive time-sink for someone with my casual assembly language knowledge. I'm sure the logic programs are very interesting but I'm not that motivated! I think some for-profit 928 folks were looking into their controllers at one point in time. Porsche published a 1988 SAE paper on the PDS all-wheel drive system which probably mirrors much of the 959 awd logic, and certainly the 964 C4 logic, but it requires some dedication to study.