# Using SEM to control Haldex. Possible?



## vr6swap (Aug 17, 2001)

Haldex, from what I understand, uses a stepper motor to control how much power is sent to the rear wheels. 

A least a couple brands of standalone offer channels that can be configured to control a stepper motor. Lugtronic for example. 

With that, could a standalone ECU be configured to control Haldex, using a stepper motor control output referenced off the boost controller or TPS. 

I have emailed Kevin Black to ask about this, but he has not as yet replied.


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## vr6swap (Aug 17, 2001)

Bueller?


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## Salsa GTI (Aug 29, 2000)

THe haldex is not as complicated as people think it is... its really a simple device it has an oil pump that runs when the car is running and the computer controls the solenoid valve to engage the clutches... most stand alone systems can be configured to control it....via TPS or boost pressure rpm or a mix of these....
Stand alone is your best friend learn it live it love it....never look back


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## Jckl (Aug 29, 2004)

I had heard that Megasquirt was going to beused to control it in the past but have not heard/seen anything on this.. I also interested in this as I plan to be running Megasquirt on a car with a Haldex in the future and would like to control the system with a standalone device.


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## vr6swap (Aug 17, 2001)

There has been some talk of ms3 being capable of haldex control, but don't know if anyone has made it work yet (or even gotten past the point of arguing about it on the immrntz). DIY Autotune info states the MS3-Pro ECU has CAN and digital input capability. Using this I assume it could control the Haldex stepper motor with the right programming. 

I did find a couple posts by a guy who claimed success using Autronic and a mystery "control box". This is plausible as Autronic does reportedly have a couple input channels that can read wheel speed. No further info was made available about the "control box". 

At this point I have found several options for locking up the Haldex at 50/50 using a simple on / off actuation. SQS makes a variable valve but it's still on / off at whatever percentage the valve is set for. 

zwogti has been able to make his car work fairly well with an SQS type valve and a Hobbs switch. He has posted a few ride along videos on YouTube. 

Dutchbuild still has their controller listed on their website. I haven't asked about availability or current pricing. 

F-Town Street Machines is no longer advertising their controller. Not sure if they are still in the market. 

HPA has made claims their new controller can be made functional as a standalone unit. When and if they ever get it to market. 

For his part, Jeff Atwood at United has stated he can do flash programming of the stock system to allow use as a semi-standalone unit. It requires using the mk4 engine management and ABS system for throttle position and wheel speed but steering angle and ESP can be coded out. 

I realize that's outside the scope of the SEM forum but just getting the info out there


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## Jckl (Aug 29, 2004)

I knew most of that but it is good info indeed. I am running MS3 on my daily and it has CAN.. Maybe I need to look into controlling it and when the time comes create something of my own if nothing is done before then or just write some code that could be built into MS.. I remember some talk about MS not wanting the liability on programming DBW but I assume the system could be designed without that. I initially planned Megasquirt for my build but was suggested to keep ME7.. Maybe Paul or someone who has more experience could provide more insight to the capability of Megasquirt controlling it. Would be nice to see control built into both Megasquirt and Lugtronic.


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## vr6swap (Aug 17, 2001)

If you're designing a system from scratch you could probably use just front / rear wheel speed (all four would be best but two would work), throttle position, a brake safety switch, and maybe a boost reference option. Like if the processor saw more than about 5-8% difference in wheel speed front to rear, at more than XX% throttle opening (or 5 - 6psi on a boost signal) it would start engaging the rear wheels starting at 20-ish percent ramping up to 50/50. You could certainly add more features or optional settings if you wanted, I'm just suggesting a bare minimum. 

Drive-by-wire, while it does (arguably) provide for more precise control of the ECU maps, it isn't really necessary and could complicate things without providing any clear benefits. We ain't going to the moon here. 

The big issues I see would be 1, does MS actually have the capacity (memory + processor speed) to handle an indirect function like Haldex without requiring an outboard controller ( I know both Lug and MS can be configured for traction control and boost-by-gear) ; 2, can the MS code monkeys write a program to handle it; and 3, how to reverse-engineer the CAN signal from the Haldex so MS can communicate with it directly?


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## carsluTT (Dec 31, 2004)

boy oh boy...... if ms3 could run haldex without voodoo .... that would open up a lot awesome!


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## vr6swap (Aug 17, 2001)

I think it could be done. Will probably have to be megasquirt and developed by a user, as its a tiny market and nobody could justify absorbing the R&D cost.


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## Jckl (Aug 29, 2004)

We shall see what happens when the time arrives. If I decide to take something on when I am at the point of figuring out my controller, I will def keep you and this thread in mind..


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