Somebody PLEASE do a direct PWM turbo controller already!!!

With VK turbo swaps becoming more-and-more common, I cringe at being forced to remove the electric actuator and replace it with a vacuum can actuator to get the turbo to work with these engines.

The signal from the ECU to the N75 is already PWM. The VK actuator is already PWM. How ridiculously stupid to communicate those two signals with vacuum instead!?!?!

It's like having an English-speaker wanting to say something to another English-speaker, but having a translator in another language in between. REDUNDANT!!!

Let's do it already. Let's make it a goal to get something done by TDIFest this year. This is $MONEY$ people!!!

Sometimes opportunity doesn't knock, it just sits in the corner waiting to be noticed...

Anyone know the PWM frequency of the ECU and the turbo actuator? I suspect there's already something out there that can be used directly or adapted without much trouble. For instance this...

i would love to get rid of the n75 and use an electronic actuator for my scirocco swap, since i'm planning on a 2260vk of some sort.. i'll be a guinea pig if *cough* someone wants to do my tuning

This should be fairly simple but a lot of work.

Is the Frequency of the N75 system and the electo-mechanical system the same?

Is the duty cycle and requested boost of each system the same for both systems or for that matter are they even linear?

Beyond just the multiplier, range and scaling may be an issue...

Subscribed.

I would think that the vacuum/spring system acts as a buffer of the forces required to adjust the vanes inside a pressurized turbo with a lot of exhaust volume wanting to move the vanes.

I see this needing something pretty robust and or strong(read expensive) to be able to directly compensate for the forces reacting on these vanes.

I also don't see a strong enough linear actuator that is small enough to fit in our compact install area, and be able to hold up to the heat that is nearby in the long term

with that said, someone prove me wrong..

Several models have direct acting servos on their turbochargers. MB uses them and I think the V6 TDI does as well?

-J

The BKW does. Two of them. They use their own paired wire engine communication bus to control them however. May not be able to work the same way.

This was a topic on this board for a while
You can`t use the VW actuator because they have a Can signal.
The Mercedes actuator used a PWM.
You can build a Frankenstein bedween Mercedes electronic and VW Mechanic that can work.
It is shown on the vid.
http://www.youtube.com/watch?v=NQ36-fiV3Vk

http://www.youtube.com/watch?v=q0qEYEmnLvY&feature=related

The main Problem ist to adjust the ECU to work properly.
I used the old vacuum actuator because i haven`t so much space left with this turbo.
Best regards Christian

I was just pulling up a V6 CDI Sprinter wiring diagram as you posted that, Christian!

So these are CAN and not PWM?

Not sure which one you have pictured, but the BKW's turbochargers (V10 T'reg here) have 4 wires to each actuator: power, ground, and hi-low CAN. Pretty simple, but you have to have the ECU to talk to them. The 5th pin is not used.

I will change from vacuum actuator to electronic on my E320 EDC15.
Software architecture for EDC15 used with PWM electronic actuator is already done by OEM ;-)

Dave if you are interested I give you a hint via PM as I don't want to spread this around www yet ;-)

Regards Alex

It is a GTB1756VK

snakesausage said:

It is a GTB1756VK

Click to expand...

Yes, but what was it used on as OEM? What model car and/or engine code? I may not be able to look at a wiring diagram, but perhaps some of our friends from the other side of the pond can.

Ano said:

This was a topic on this board for a while
You can`t use the VW actuator because they have a Can signal.
The Mercedes actuator used a PWM.
You can build a Frankenstein bedween Mercedes electronic and VW Mechanic that can work.
It is shown on the vid.
http://www.youtube.com/watch?v=NQ36-fiV3Vk

http://www.youtube.com/watch?v=q0qEYEmnLvY&feature=related

The main Problem ist to adjust the ECU to work properly.
I used the old vacuum actuator because i haven`t so much space left with this turbo.
Best regards Christian

Click to expand...

Christian, if you did that work, excellent!! Right, no need to reinvent anything here. Just use a PWM actuator, e.g. from a Mercedes-Benz and others too (BMW?), and get the ECU signals to work correctly on these actuators. The actual mapping for the differences in dynamic response should be simple enough.

One would think Bosch' EDC15 would be similar enough across brands to make that not too difficult. One would think. Of course, VAG punted on the CR for PDs instead, so....

It is the same turbo that Ryanp uses in his kit before he changes it over to vacuum. I am not sure what the OEM application was.

http://www.darksidedevelopments.co.uk/products/garrett-gtb2260vk-and-gtb1756vk-turbochargers-with-vacuum-conversion.html

oilhammer said:

Yes, but what was it used on as OEM? What model car and/or engine code? I may not be able to look at a wiring diagram, but perhaps some of our friends from the other side of the pond can.

Click to expand...

I haven`t build this sorry.
I have searched this because i have the same in my mind before i build it like all others.
The Turbo can`t be screwd like before because of the position of the actuator.
Best regards Christian

There may be some improvement in spool if this actuator works well. 2260 Turbo can spool quite a bit better, but some instability in vacum vane control precipitates surge. It is made worse with larger compressor wheels.
Ultimate would be to have positional feedback, but I am not sure if edc15 can be adapted.

Remapping for custom vane duty cycle is relatively easy, but time consuming.
Some adjustment of PID variables might also be required, but I could not find any firm information on the edc15 variables, and my experiments were hampered by the vloggocds data logging speed.

What is the actuation method of the GTB series turbos? Yes, it takes in a PWM signal, but I'm assuming that there is some sort of micro controller inside that takes the PWM signal and turns it into actuator travel - maybe via stepper motor/leadscrew? - Power, ground and PWM signal input (relative to ground)

I'm assuming that the PWM driver in the ECU has some sort of current feedback on it (otherwise how would it know if the N75 is electrically disconnected and then throw a fault code) so you need to fool the ECU to thinking it's actually driving a load.

If the PWM frequencies are the same, maybe this is as simple as leaving the N75 coil hooked up electrically and just tapping the signal from the two wires to go to the high impedance (also an assumption) input of the GTB actuator? Nothing fancy needed?

I think the two things we need to know to get started on this are

1) What frequency is the GTB actuator looking for?
1a) What is the load of the PWM Signal to the GTB actuator?
2) What frequency does the EDC15/16 drive the N75 valve at? (looks like 250Hz).

One more thought...is the GTB actuator expecting a constant frequency with a varying duty cycle (10-90% for example) or is it expecting a constant duty cycle (50%) and a varying frequency (100-200Hz). I've seen controllers that want to see both (one or the other) types of PWM signals.

Check this out between 1:40 and 2:00 - constant frequency ~140Hz, variable duty cycle.

Is this a GTB actuator?

There are 3 types of electric actuators

Type 1, oldest - it don't have controller build in. It exposes 2 pins for the motor and 3 pins for the position sensor. This one can be made to work with external controller (easily build) for servos. It just has to be programmed to work on 140hz. This is the most common one on GTB1756VK and GTB2260VK from VAG engines.

Type 2, the easiest one to get working. Is has build in controller that works on 140hz PWM. Exactly as the N75 input. It is direct hardware plug&play and only software modifications are required. I think Ford 2004 2.0 turbo diesel has such. Not sure what else have it - some MB also do, but not sure what models.

Type 3, the new one. It is CAN controlled. It keeps even history of the required power to move the vanes, temperatures and stuff that can be used for debugging. I think that there are some researches about the protocol that control it, but I'm not sure. This one should be the hardest to get working on EDC15 ECU that outputs PWM.

By the way I started some research about controlling the type 1. But I stopped it as the turbo needs to be clocked to fit on the Passat and the actuator will not be in the correct position. I thought it would be plug and play at the beginning, but the actuator will come just under the filter box. And I want to keep mine .

Thanks brum, now get at it, guys.

One has to ask.... if it ain't broke, why "fix" it?

I think we use the vacuum actuators because it's easy to make them work on VE cars without major software changes.. Just make the actuator fit on and adjust it and you're good to go..

Vacuum is fine if you're dealing with only one turbo and an old-tech one at that........