[WIP] Porsche 981 Cayman S

Tell us about the project you do with the open inverter
Mitchy
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Re: Porsche 981 Cayman S (2014)

Post by Mitchy »

Cluster / OEM Integration

This will be a dumping spot for some of the fine details for the integration.
Also to document some of the Fails of the journey.

Cluster:
I was hopeful that the engineering option of turning on the Hybrid menus in the Gateway/Cluster/Radio modules would allow me to hijack the existing hybrid integration.
Hybrid Menu.jpg
Hybrid Screen.jpg
Unfortunately after many trials I'm pretty confident that the 991 and 981 cluster firmware lacks any deep hybrid integration.
For those wondering, you can flash a Cayman cluster with 991 firmware and gain the few perks of the 991 (better selection of the lcd panel)
But even with the latest version, the cluster fails to read the ECU Hybrid canbus signals and thus cannot forward the signals onto the PCM/Radio.
PCM Hybrid 1.jpg
PCM Hybrid 2.jpg
PCM Hybrid 3.jpg
I have a feeling the Panamera/Cayenne clusters would work, but unfortunately these were made by VDO (vs Contentinal for the 991/981/macan versions) so the code is most definitely incompatible given the blocksize for the bootloaders are different.
I may try to pickup a cheap cluster to map the signals sent to the PCM to display the battery and charge status there.

Also fighting being unable to find any documentation of the BAP protocol to the PCM.

I've managed to identify 0x10E (I believe, need to check my notes) if you spoof this on the MMI bus it'll toggle the E-Range value.
Eventually I hope to just have a small CAN-in-the-middle to adjust these values to the PCM if I can't sort out the actual cluster forward
With PIWIS you can also toggle the AWD screens and mimic the Allrad block to show the torque distribution.

Some AWD cluster warnings can be triggered by 0x105, though I haven't seen any DBC showing the full breakdown, I can post the info that I've found from spoofing.
There is an AWD screen that should be easily enabled much like the hybrid screen, but on the 981/991 images this screen option does not appear. I doubt there is any selective logic on Canbus signalling (and no errors from the cluster complaining about a missing canbus message)
I was going to try the Macan cluster firmware to confirm the hybrid and AWD screens are missing from that one as well, but that may be too risky.

Finally, you can adjust the cluster bar graph scaling for most of the values, so it's easier to better represent the cooler coolant temps and such related to the electrification, as well as adjust the oil pressure and other items to better represent whatever you need them to. 🙂


Gateway:
Looking into if there's an updated firmware for my existing CAN gateway.

Like most VAG cars, there are only a few different modules, and most are used elsewhere in the model lineup.
Unfortunately the module I have is the 7PP.907.530
There is a 95B module, this is the macan module, but also used in the 918 and most of the later model lineup. This module seems to have many more configuration options.
Unfortunately due to the component protection, I can't just swap out the modules without dealer reprogramming.

My Gateway is ver A4.2
The 95B module is A7
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Re: Porsche 981 Cayman S (2014)

Post by Mitchy »

HVAC System

I'll list some details more related to the HVAC integration here.

My base plan is to use the HVAC CAN status signals to drive a VAG HV compressor.
I may try to investigate other options, but from the initial testing the canbus should give me everything i need to know the demand required.

Initially I'm just going to have cabin AC,
We rarely see 20*C ambient locally here so either way AC is low priority for both occupant and battery :o
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Re: Porsche 981 Cayman S (2014)

Post by Mitchy »

12V Battery System

The Porsche system uses a Battery Management System.
This is easily bypassed, but I may try to work within the confines of the system.

Haven't dug too deep into this system yet either, but it'd be ideal if a VAG charger using the existing alternator LIN protocol exists.

The best example I have to this is the 918 Hybrid... From what it seems it uses a similar BEM module.
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Re: Porsche 981 Cayman S (2014)

Post by EV_Builder »

Wow cool mods! How did you turn that on?
Did you use PIWIS II?
Does it involve re-programming multiple devices?
Converting an Porsche Panamera
see http://www.wdrautomatisering.nl for bespoke BMS modules.
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Re: Porsche 981 Cayman S (2014)

Post by Mitchy »

I've been using a PIWIS 3 38.500 image, along with a VAS6154 interface.
I can give you more detail of my setup if you need (and image), it's easy enough to setup if you want.

Another positive point is that it'll still identify all modules with the ECU/TCU missing. The only issue is the automatic model selection, but all other diagnostics work, easy to tell if any module isn't happy with the bus signals.

Most of the modules have some sort of 'Hybrid' mode, either selected directly via the engineering interface (Cluster, Gateway, PCM) or by reading the MotorCode Canbus message, when this canbus bit is coded to full hybrid, a few other modules follow along (EPB, EPS)
I believe the only difference for those modules which read the motorcode from the Bus is their reaction to the motor running status; basically eliminating the need to have a >600 RPM signal.
My EPB module isn't totally happy with the change, giving a configuration error, so I may roll back after some additional troubleshooting.

Your Panamera cluster should be able to do the hybrid signals, if you enable them and spoof some signals into the Motor_Hybrid can addresses in my notes, it'll be interesting to see what you get as a result. You should also be able to swap to the powermeter dial if you can find a cluster with it, that dial (and the battery gauge) would be an awesome swap to better show the power/regen in the factory cluster.
the PIWIS images have some firmware included.
If you do this a log of the MMI bus during this would be very helpful!

I've updated the OEM integration post above with some more info related to the MMI bus and Cluster screen/AWD error messages:
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Re: Porsche 981 Cayman S (2014)

Post by Pete9008 »

Mitchy wrote: Thu Sep 29, 2022 10:32 pm Brake Booster:
The Audi 4M2 brake booster has been mounted, this wasn't too difficult but needed about 8mm trimmed from the bolts and an M10 extension placed on the rod to correctly use the existing Porsche ball mount
The Porsche booster is basically identical to all VAG parts from 97 Jettas onward.

The Audi Master Cyl was re-used, but the aux port for the pressure accumulator was plugged. this is a 2nd line off of the rear brake port.
I've confirmed that the existing Master Cyl is a 26.5mm unit and similarly sized to the GT3 booster upgrade that is common (27mm I believe)

If i was to re-do this, I'd suggest just getting an aluminum spacer fabricated to space it slightly from the firewall. This also would address an issue with the brake lines which are routed behind the booster unit being a bit too close for comfort, I solved this by bending them slightly, but to keep the lines totally factory, a 1/4" spacer would be perfect.
Superb work :)

Do you know whether the VW iboosters are CAN bus or Flexray (or do they support both)?
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Re: Porsche 981 Cayman S (2014)

Post by Mitchy »

Pete9008 wrote: Fri Sep 30, 2022 11:01 am Do you know whether the VW iboosters are CAN bus or Flexray (or do they support both)?
I've been digging into this lately,
From all the VCDS configuration items I can find for this unit, there isn't any switch to swap between CAN/Flexray
The unit I have is unfortunately Flexray.
There are many VAG Canbus boosters though.
eBKV is the module description, and in the VCDS world it's Module 23.

From some quick research there are multiple PartNumbers, but likely just 2 real HW versions
On the tag, you'll see H14 0195, I'm thinking the H14 is the HW# and the 0195 is the SW number
From VCDS maps, there are only 2 types of Units (regardless of the external PN):
  • 3Q0 modules are H06
  • 5QE modules are H14
It's possible that this is the CAN/Flexray split.

There are other modules, like the 918 Spyder uses a Bosch eBKV which is H09 1200, I've been trying to find one to attempt to crossflash the 918 firmware.

In the end, it looks like the control module can be removed from the eBKV module, The only reason I chose this particular unit is that it fit the existing bolting pattern, so I'm curious if the modules can be swapped.

The Flexray units also have CAN, but it seems that this is an AUX bus used to communicate directly with the pressure reservoir (VX70)
Screen Shot 2022-09-30 at 9.10.22 AM.png
Screen Shot 2022-09-30 at 9.10.05 AM.png
Screen Shot 2022-09-30 at 9.10.44 AM.png
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Re: Porsche 981 Cayman S (2014)

Post by Pete9008 »

Thank you! great information :)

So are you thinking that the 3Q0 modules are the CAN bus version?

I'm considering the VW ones as I believe some of them have smaller bore master cylinders which would be a better match to the current master cylinder than a Tesla one.

I have an old copy of VCDS somewhere, I'll dig it out and have a look.

Once again thanks for the reply.
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Re: Porsche 981 Cayman S (2014)

Post by Mitchy »

I'm not too confident that the 5QE modules are flexray only, as it seems they're used in the Mk7 and it appears that they're still using powertrain CAN connected on Terminals 16(CAN-L) & 25 (CAN-H)
If you notice the Q7 wiring terminations in my previous post these terminals are unused, so I'm likely going to attempt to connect up to these terminals in hopes that CAN is enabled.

I have a compilation of VCDS Maps comparing various models, but I need a few datapoints with those cars with Flexray to really confirm if there's a flexray interface 'switch'
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Re: Porsche 981 Cayman S (2014)

Post by Pete9008 »

Definitely well worth checking. It wouldn't be that surprising if the CAN interface was still there. Whether it needs enabling or another software version is another matter though.

Following with interest.
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Re: Porsche 981 Cayman S (2014)

Post by Pete9008 »

Are you hoping to modulate braking assist over CAN or just read out the position? The former would would be very nice to have but I'm not aware of anyone having worked out how to do it yet.
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Re: Porsche 981 Cayman S (2014)

Post by Mitchy »

Axles:

A relatively major milestone.
After some/many hours of measurement and trolling thru various online catalogs, I managed to find some suitable CV axle shafts.

For Stub Axles, I purchased the Zero-EV 930 stubs during my mockup phase as I knew I wanted to stick with as close to a factory axle as possible.

For options:
  • Custom route, Lots of 930 type axles used by the Sand Rail crowd.
  • Air-cooled 911 axles have quite a few variations, but most likely to have some incompatibilities of the newer style hubs.
  • 986/996 shafts are suitable, these use ABS rings which can be removed, the rings likely would clash with the newer hubs, ~26mm shaft size
  • 987/997 shafts are equally suitable, no ABS rings. These newer ones have a larger diameter shaft of ~30mm
For the newer shafts, several different lengths. Trakmotive is a good source for measurements http://www.showmetheparts.com/trakmotive/
Trakmotive measurements are a bit unconventional as they're a 'tip-to-tip' measurement, taking in account the end threads and the 930 'bulb' that is on the end of the cv joint that recesses into the stub shaft.

Key to Porsche Axles is the 108mm '930' flange and 28 spline hub.

Porsche Axles and their compressed lengths are below:
VW-8164 - 653mm - 986 Boxster - 2.7L Manual - Left
VW-8165 - 694.5mm - 986 Boxster - Likely Superseded with 8180
VW-8166 - 563mm - 986 Boxster - Likely Superseded with 8167
VW-8167 - 563mm - 986 Boxster - 3.2L Auto - Right
VW-8168 - 682mm - 986 Boxster - 3.2L Manual - Left & Right
VW-8180 - 696mm - 986 Boxster - 2.7L Manual - Right
VW-8118 - 689mm - 997 Carrera

Having the 997 I did some initial measurements
Given that the VW-8118 shaft was the cheapest @ $90 ea on RockAuto, I ordered one... Then Another :)

Once installed, the total compressed length gives me 22mm of plunge space per side when the suspension is loaded with the axles totally horizontal, 22mm of the ~70mm of full travel is reasonable, as this gives 30-40mm of play at full droop or full compression.

Since the 8118 shaft appears to be also used on the Turbo models, upgrade paths are easy with various larger axles available - From Driveshaftshop and others using fancy 300m .
Shaft PartNo & Dia.jpg
From Below.jpg
Right SIde.jpg
Left Side.jpg
No bolts or anything yet as I'm still mocking up, But it all looks promising!
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Re: Porsche 981 Cayman S (2014)

Post by HawkHP+ »

HI Mitchy,

Just curious if you have extra set of the mounting bracket/hardwares for the the Cayman build , if so, I want to buy a set from you, let me know thanx
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Re: Porsche 981 Cayman S (2014)

Post by Mitchy »

Quick update,
Ibooster is installed, the Aux CAN has some info that represents pedal position:

More info here: viewtopic.php?t=2699
Managed to get the PCM hybrid battery level and hybrid flow working:
Out@100%.gif
Regen@40%.gif
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Re: Porsche 981 Cayman S (2014)

Post by Bratitude »

when it comes to VW axles, there's a few different spline types, but they are available in a variety of lengths
https://www.pacificcustoms.com/porsche- ... axles.html
https://bratindustries.net/ leaf motor couplers, adapter plates, custom drive train components
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Re: Porsche 981 Cayman S (2014)

Post by EV_Builder »

Mitchy wrote: Sun Jan 29, 2023 9:30 pm Quick update,
Ibooster is installed, the Aux CAN has some info that represents pedal position:

More info here: viewtopic.php?t=2699
Managed to get the PCM hybrid battery level and hybrid flow working:
Out@100%.gif
Regen@40%.gif
Woww ...hey i like this idea...
Converting an Porsche Panamera
see http://www.wdrautomatisering.nl for bespoke BMS modules.
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Re: Porsche 981 Cayman S (2014)

Post by spiff »

Mitchy wrote: Wed Oct 19, 2022 12:20 am Axles:

A relatively major milestone.
After some/many hours of measurement and trolling thru various online catalogs, I managed to find some suitable CV axle shafts.

For Stub Axles, I purchased the Zero-EV 930 stubs during my mockup phase as I knew I wanted to stick with as close to a factory axle as possible.
Hey Mitch,
Are you saying the ZeroEV stubs will bolt onto the 987/997 axles and all you have to do is find the right length of axle? No machine required?
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Re: Porsche 981 Cayman S (2014)

Post by Mitchy »

Yep that's correct
The ZeroEV stubs are just 108mm bolt spacing, so basically any 930/Newer Porsche axle works without issue.
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Re: Porsche 981 Cayman S (2014)

Post by Mitchy »

In addition to the Sport LDU in the rear, I'm hoping to run the Raven Front Drive unit from a newer Tesla Model S.
The Raven is basically a Model 3 Performance Rear Drive Unit, but in a Front Drive Unit form factor.

The Openinverter community are making real progress getting the Model 3 drive units working, and this has the same base inverter as the 980 drives.
Raven Front Cayman.JPG
<--- Vehicle Front // Vehicle Rear --->

Realistically it's a crazy tight fit. A Co-Axial unit would be a much better fit;
Since no scans or measurements were online for the Raven, I found a unit cheap enough to take a chance and give back to the community in the form of a 3D Scan of the drive unit for others to use:

It's uploaded to GrabCad:

Tesla Model S - Raven front drive unit scan
Raven.png
Motor positioning from Tesla is slightly more tilted than what is shown above,
On the bottom of the Diff, there's a Part# tag, Assuming that the tag being level would be the true position:
Image
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Re: Porsche 981 Cayman S (2014)

Post by EV_Builder »

Boy you are doing great here.. ; can you indicate normal model S position of the unit? Is vehicle in the picture nose up or down?
Converting an Porsche Panamera
see http://www.wdrautomatisering.nl for bespoke BMS modules.
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Re: [WIP] Porsche 981 Cayman S

Post by Mitchy »

Quick Update:

Started integration of the Zombieverter VCU.
I've been poking at the firmware with a bench setup for a while, but finally getting it installed and working out some of the vehicle interface is quite enjoyable; So Far here's what I have integrated (or prepped for integration)
  • Sport Mode
  • Electronic Parking Brake Status & Clamp Force
  • ESP/Traction Control Status (to enable/disable OI Traction Control
  • Various Warnings & Cluster Messages
  • DC/DC Voltage Setpoint (VAG Cars have a Battery Energy Module, which calculates the alternator voltage setpoint)
  • A/C Compressor Request & Desired RPM from Climate Control Module
  • Level of Heating Request for PTC Heater (High/Low/Off)
  • Wheel speeds & Overall Vehicle Speed
Thus far I've been able to simulate all the signals to the point where there are no system faults within the vehicle.
Annoyingly, there's quite a bit of consistency checking in each module, so for instance the ABS module retrieves the brake signal from the BCM module, but also cross checks with the ECU Brake Status.
Canbus msg output is tied to T15 status, after key off the VCU goes quiet and after a timeout period all other modules on the bus go into sleep mode
Zombie is now sending out about 1000 msg/sec to the vehicle bus.

I'm using the stock shifter, which also means using the stock shift lockout solenoid, I'm using the VCU GPIO out to energize the solenoid.
VCU is also energizing the DME relay, which has Fans and Aux equipment connected, so power is only applied to those during On or Charging mode.
Will likely repurpose the Fuel Pump solenoid for the Inverter power output signal.
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Re: [WIP] Porsche 981 Cayman S

Post by Mitchy »

LDU First Spin!

Managed to spin the LDU using Can-Bus control via the Zombie VCU.
Rev Gauge uses 650 RPM for 'idle' with the motor RPM shown as RPM/2 to correctly scale with the 9,000 RPM redline.

Excuse my Mess of a workbench!

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