GT500 engine + DcT in a GT350 doable?

[T7TheLama]

Ok couple of updates. Drove the car for around 1000km so far so good)!
I'm currently in the process of making the oss sensor behave correctly for cruise control.

In the TCU software i can change a couple of settings. (VSS=OSS)
1) VSSPull Up 2.2k ohm (active)
2)VSS Sensitivity Voltage (currently 2.5V)
3)VSS Multiplier (currently 11.95)

VSS Multiplier is 60 tooth x ~12 = 720 pulses, so like oem

With that multiplier set the oss from the tcu and the pcm match and cruise control works again (for 20 minutes or so)

Issue is after sometimes 20 minutes or 1 or a hard pull i get a see manual error (DTC U0401)

After that i flashed the pcm with Hptuners to somewhat match the 8 gear ratio in a 6gear table.

Which seems to have done something but not with the error(( The active exhaust close works again but this time in 8 gear instead of 6/wish it didn't work haha. But i found out in Hp tuners you can now make the active exhaust behave like you want.

After playing a bit with forscan i looked at the signal from the oss sensor that the pcm receives (the green line)and it looks like the pcm misses a few pulses. So for now i try to lower the voltage sensitivity to get a better reading.

If that doesn't work, i'm kinda lost on the oss stuff

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[Rodpwnz]

I gotta glaze you here big dawg, your work is truly inspirational. I’ve dreamt of the possibilities had ford gone with the ZF8…

Cherry on top is that you’re on the up and up with Akiaura - I’ve been listening to deathwish on repeat since release last week.

 

[ZXMustang]

OSS=RPM divided by current gear ratio.

Example 5000rpm divided by the 10R80's first gear ratio of 4.69 would be 1,066 OSS. And it works in reverse. 1,066 x 4.69 = 5000rpm.

You need to know the 8 speed auto's gear ratio's for each gear. Then you can work out OSS per gear for what RPM scenario you are wanting - like part throttle shift or WOT shift points...

 

[ZXMustang]

From my Ford tuning trained AI.

Confirmed. The Turbo Lamik TCU for the ZF 8HP70 is widely used in standalone Ford applications (Mustang GT, GT350, etc.) and is known to interface via direct analog inputs (RPM, TPS, MAP) — not native CAN to the PCM. It broadcasts its own CAN stream, primarily for dash integration and logging, not for OEM-level ABS or PCM sync.

Here's what’s happening:

1. Cruise works at firstbecause VSS is being accepted by the GT350 PCM — likely from either:
   • ABS module (still active), or
   • the Lamik controller broadcasting a pseudo-VSS on the right frequency.
2. After a certain runtime or a heavy load event:
   • PCM performs a CAN message integrity check on 0x0A5, 0x0AA, or similar.
   • If the CRC, length, rate, or checksum fails — or if messages vanish (e.g., ZF TCU enters limp or resets) — DTC U0401 is triggered.
   • Cruise cancels, PCM exits decel fuel cut, torque arbitration errors cascade.

GT350 PCM Requirements Recap (for cruise to remain active):

Signal	Source Requirement	Method To Satisfy
VSS (0x0A5)	ABS-style CAN at ~10ms interval	Emulate using CAN bridge/gateway
Brake status	ABS module, 0x0AA	Emulate or keep ABS module present
Engine torque	PCM internal	Already present in GT350 ECU
No CAN error	No conflicting TCU messages	Filter or isolate Lamik TCU broadcasts

Recommended Fix Strategy (Specific to Turbo Lamik + GT350 PCM):
1. Retain ABS Module (even standalone)

• It’s the cleanest source of 0x0A5.
• GT350 cruise logic relies heavily on ABS-derived speed and brake status.
• Even if ABS is not controlling brakes, it can function as a VSS/CCM emulator.

2. Use CAN Bridge to Block or Filter TCU Conflicting Messages

• If the Turbo Lamik controller is broadcasting VSS or torque on conflicting IDs, PCM will reject them after ~20 minutes.
• Use a tool like:
  • CANBed Dual
  • SavvyCAN + GVRET
  • PiCAN2 + SocketCAN
• Filter out or rewrite the TCU’s VSS broadcast to prevent PCM arbitration failure.

3. Don’t Rely on Lamik’s VSS → PCM Behavior

• It was never designed to satisfy Bosch MEG17.8.8 cruise or torque arbitration.
• It works enough for the car to drive, but fails strict cruise/timer-based validation.

Actionable Options:

• You want cruise to stay active:Build a small CAN bridge to either:
  • Re-emit a valid 0x0A5 ABS message using ZF OSS data.
  • Block conflicting CAN IDs from Lamik TCU after initial boot.

I can supply exact Ford ABS 0x0A5 message structure and CAN bridge code if you tell me what hardware platform you're using (e.g., ESP32, Arduino CAN, PiCAN). Want to proceed with building the emulator?

 

[T7TheLama]

After wrist surgery, I’m back at it, still working on the frustrating VSS/OSS issue. At first, I tried using a Schmitt trigger to clean up the signal into a proper square wave, but I’m still getting the same random dropouts lasting about half a second. That makes me think it’s not a signal quality issue, but more likely the TCU introducing slight errors that are tolerable for the tachometer but not acceptable for the PCM i guess. So, I’ve decided to ditch the VSS output from the Turbolamik entirely and go with an external sensor instead.

For that, I needed a new output flange with an integrated tone ring. On the left is the old setup, on the right is the new single piece flange that also replaces the OEM output flange.

Red is the new OSS sensor just need to wire it in. Additionally I need something too divide the signal. I'm pretty sure the OEM teeth count is lower than I have.

 

[T7TheLama]

Okay, I've got the setup running. It reads the OSS speed from the new 20 tooth flange. I'm using a Dakota Digital SGI-100BT (which, to be clear, shouldn't be used for ABS/PCM sensor data, it specifically says not to, but I had no other option). I scale the signal down by 0.6 so the PCM still sees the 12 tooth pattern it expects.

The signal is much cleaner now, but I'm still getting the same error. This makes me suspect the issue isn't with the sensor itself, but possibly with the PCM's configurable gear ratio settings in HP Tuners.

That said, the car shifts much nicer now. I figure it's either stability control cutting torque or some other behind the scenes magic trickery, but it's clear the OSS signal is affecting shifting behavior somehow.

I've attached the OSS oscilloscope Forscan data from the latest test drive.

Anyone have any ideas? Could it be the gear ratio table?

 

[T7TheLama]

Figured it out! No more errors and everything works. Cruise control, stability control, abs, no more weird things going on(:

The culprit was actually this table:

I guess something is up with the error detection so i just increased the threshold significantly.
I bet the unstable OSS also played it's role, but that is also gone.

In the field testing hehe

Working cruise control

 

[Kidd]

Great work man, very cool! Do you have a YouTube channel where you post progress info and driving videos?

 

[T7TheLama]

Great work man, very cool! Do you have a YouTube channel where you post progress info and driving videos?

I do but i haven't uploaded anything in a while:
https://www.youtube.com/@TBCTop7gear

 

[Kidd]

I do but i haven't uploaded anything in a while:
https://www.youtube.com/@TBCTop7gear

Sub’d

 

[Nfs1000f]

I do but i haven't uploaded anything in a while:
https://www.youtube.com/@TBCTop7gear

 

[T7TheLama]

Final update for the 8Hp swap for now!

I’m currently reverting back to the Tremec. I’m pretty much finished, just need to reinstall the transmission after it was repaired for 6k€ and after a 4 month wait

On my TR3160, not only did the synchros wear, but a gear on the input shaft was also missing a couple tooth edges.

Regarding the 8HP swap, the car drove fine all year and I didnt encounter any new errors.

There are a couple of reasons why I’m going back to manual. First, i got a bit bored with the automatic, bit funny and I kind of miss the manual.

The biggest (fixable) problem with my swap is the analog integration. Because the gearbox and ECU dont talk to each other, downshifts have a delay.

Under normal driving thats totally fine, but under fast driving, when you go into a corner and the car downshifts while the weight is shifting mid corner it upsets the car and makes it sketchy. Since i mostly use this car for spirited driving or track use, it kind of defeats the purpose.

The solution would be either can integration with oem Ford stuff (difficult, but doable), or the easy route with a third party controller, preferably motec to keep the stock systems working.

But not only is the controller $15k in the US, theres also no pre made harness you can buy without sending the car to a shop in the US which is pretty difficult when you are 6000 miles away.

On top of that, with the manual itch coming back, that sealed the deal for me (for now).

All the wiring I did is plug and play, so i just unplugged it. If i want i can easily reswap again later.

I also bought a whipple for a new easy and fun project. Wait time is around 10 weeks.

Probably the first supercharged GT350 in Austria.

Still unsure if im swapping the OPG/CS, and if i do, whether i will go with the boundary set or the GT500 pan + opg

I also switch the motor mounts with steeda ones to try to clear the brace, but i have no idea if thats a smart idea because of the flat plane harmonics.


First pic is the input shaft, the rest is throught the year

 

[Rodpwnz]

While a bit personally and selfishly dissapointed since this project realized my dream of a ZF8 instead of my 10r80, I think it's great that you're going back to the Tremec since that is what you really want.

Feels somewhat absurd that a Motec controller is $15K...but maybe they know their demographic and audience better than me.

Commendable efforts, and a really cool project to have followed though! Thanks for sharing!

 

[T7TheLama]

While a bit personally and selfishly dissapointed since this project realized my dream of a ZF8 instead of my 10r80, I think it's great that you're going back to the Tremec since that is what you really want.

Feels somewhat absurd that a Motec controller is $15K...but maybe they know their demographic and audience better than me.

Commendable efforts, and a really cool project to have followed though! Thanks for sharing!

Project was basically finished already. I only recommend going for a third party controller for a true performance feel.

Everything else worked like a charm and all the error's got fixed (:!

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