Author Topic: aftermarket controller to control a VNT? (Read 20635 times)

ezekiel · « **on:** September 04, 2006, 11:01:12 pm »

I haven't been thinking much about my motor lately, but I think my Rabbit is dieing, so I need to. Since I already have a TDI VNT, I'm going to use it on my AAZ.

Is there any reason that I can't use some sort of fuzzy logic controller, like a GReddy Profec and a strong vaccuum pump (possibly a second, dedicated one?) and let it control it like that?

Or, if that doesn't work, maybe take a microcontroller of some sort to make a solely RPM dependant boost control using an N75 valve?

rabbid79 · « **Reply #1 on:** September 04, 2006, 11:06:47 pm »

I am presently working on that very thing (custom controller) for my VNT Rabbit. IM me, and I'll fill you in on the specifics you'd like.

OM617 · « **Reply #2 on:** February 04, 2007, 09:57:05 am »

Just replace the vacuum actuator with a boost actuator from a normal turbo.

foxracer1 · « **Reply #3 on:** February 04, 2007, 11:22:29 am »

Quote

Just replace the vacuum actuator with a boost actuator from a normal turbo.

And that works safely? Some guys have brought up the possibility of a failure and the vnt sticking at max boost.

Benjamin · « **Reply #4 on:** February 04, 2007, 11:26:42 am »

you can rebuild the stock actuator, there is a hole, in the actuator, if you can make a pin on it, you can use this one. some guys did flipped the internals, some guys use an actuator from a wastegated turbo.
You can also use a external wastegate, but you dont NEED it.

more information can also found in the search

Greetz, Benjamin

OM617 · « **Reply #5 on:** February 04, 2007, 11:37:57 am »

My turbo tops out around 13psi with the vanes wide open so no wastegate is needed. The actuator I use is from a Saab 9000 LPT and it maintains a steady 9psi of boost all the time. I'm currently working on a two step boost controller that will allow me to run 15psi at full throttle and 9psi the rest of the time. LINK

Quote

And that works safely? Some guys have brought up the possibility of a failure and the vnt sticking at max boost.

That's part of the risk when building custom setups. I've got the stock Mercedes overboost switch (16psi) wired to a $2 RadioShack 12v buzzer. It's loud enough to hear over the radio and engine in the event boost control fails.

Tintin · « **Reply #6 on:** February 04, 2007, 11:40:42 am »

Quote from: "foxracer1"

Quote
Just replace the vacuum actuator with a boost actuator from a normal turbo.

And that works safely? Some guys have brought up the possibility of a failure and the vnt sticking at max boost.

Yes, it is not the best way to control a vnt , with large turbo it is less worse, but with this type of assembly will always have you max boost can imports how you run.

For an electronic control, that will take a sensor for indicated the position of the accelerator, the position of the RPM, boost sensor, and etc....

You can also make you a mechanical control, it is easy to make and that do not need precision to control the vanne, easy to adjust and cool to see :lol:

foxracer1 · « **Reply #7 on:** February 04, 2007, 12:44:32 pm »

So how much boost can these make max? Does it only make 13-15 max? sounds a little low.

Slave2School · « **Reply #8 on:** February 04, 2007, 12:47:46 pm »

Quote from: foxracer1

So how much boost can these make max? Does it only make 13-15 max? sounds a little low.

I depends on the model of VNT. The standard vnt-15 in my tdi was supposed to be OK to ~17.5psi the vnt-17VB version should be able to hold 22-23psi all day long and the "vnt-20" would be going beyond that.

foxracer1 · « **Reply #9 on:** February 04, 2007, 12:53:00 pm »

Well damn i was hoping to make more than that. But i guess it is much better down low.

OM617 · « **Reply #10 on:** February 04, 2007, 12:59:53 pm »

I know it's not a VW, but the Dodge sprinter I got my GT2256V from runs stock at 19psi and I currently run 15psi on my 3L MB diesel.

Tintin · « **Reply #11 on:** February 04, 2007, 01:55:15 pm »

Quote from: "Named Tintin"

............ but with this type of assembly will always have you max boost can imports how you run.

I wants to say the max boost which you will have chosen and adjusted for your engine.

OM617 · « **Reply #12 on:** February 04, 2007, 02:00:35 pm »

Correct. My turbo always adjusts the vanes to maintain as much boost as possible up to it's maximum setting no matter the engine load or throttle application.

Turbinepowered · « **Reply #13 on:** February 04, 2007, 02:01:47 pm »

Quote from: "foxracer1"

Well damn i was hoping to make more than that. But i guess it is much better down low.

Do dual VNT 15s. Biturbo 1.6 TD! :twisted:

burn_your_money · « **Reply #14 on:** February 04, 2007, 09:21:20 pm »

Quote from: "OM617"

I'm currently working on a two step boost controller that will allow me to run 15psi at full throttle and 9psi the rest of the time. LINK

I sure hope they activate me soon so I can see what you are talking about...