How to operate vnt15 controller on 1.6L

[crazycaddy]

Well, I guess I'm just to dumb or something but I can't figue quite what is the best way to control the vane actuator on my vnt15 turbo that I have on my 1.6L. Do I use a different actuator or use a manual valve or what. Can anyone help me out on this. This engine I am biulding is an experiment.  :?

vnt15 turbo

custom IP

Merc injectors

3 inch exhaust

ect....

[Vincent Waldon]

Here's a thread over at Jack's forum that has some thoughts:

http://vwdiesel.net/phpBB/viewtopic.php?t=8065

[vwmike]

I think that setup looks more complicated than it has to be. I would think with a little trial and error you could make a normal wastegate actuator work. Otherwise I'd be tempted to run a line to the original VNT actuator with a solenoid controlling the bleed off (much like how the stock system worked). A small PWM circuit would probably do the trick.......just some random thoughts.

[crazycaddy]

Thanx guys, this at least gets me leaning in one direction. :lol:

[Audi80]

Little offtopic, but:

What merc injectors? 617? 617 turbo? 603? 603 turbo? 606? 606 turbo?

IŽd say vnt15 is WAY TOO SMALL for 1,6 :roll: At least with modded pump etc.

[rallydiesel]

I think the easiest way is to get an old wastegate assembly, take it all apart, cut off the wastegate valve off its stem, use a die and make threads on the shaft, put the can back together, screw on a turnbuckle type thing onto the shaft and screw that onto the vane actuator arm.

Then use a boost controller to set your boost. You may need to make some kind of cam system so the movement of the shaft moves the vane actuator the appropriate amount.

With that said I think VNT turbos really need to be controlled by an ECU due to the complexities of the vanes and rpms, engine load, throttle position, etc.

You can't use the actuator that's on the VNT because it works on vacuum and you need a "regular" wastegate actuator that works on positive pressure.

[jimfoo]

With that said I think VNT turbos really don't need to be controlled by an ECU. Due to the complexities of the vanes and rpms, engine load, throttle position, etc, a controller like Named Tin Tin's, Libbybapa's or Jimfoo's works just fine.
You can use the actuator that's on the VNT if you take it apart and convert it to work off boost instead of vacuum..

Fixed it for ya.  :roll:  :wink:

[OM617]

I use a VNT with a regular pressure actuator (wastegate actuator). Click on my "GT2256V" link in my signature.

That method works fine as a "get it running right now" option but it is not acceptable as a long-term solution, especially if you want high boost pressures. From everything between idle and your set high boost pressure, the vanes will be closed all the time. This is because the actuator will try to make the turbo get up to your set maximum boost regardless of engine load, engine speed or throttle position.

All that does is restrict the exhaust during low load situations (Idle, cruise, light acceleration, etc) which kills fuel efficiency. It makes the engine work hard to push the exhaust out of the cylinder and through the narrow restrictions of the closed vanes.

IMHO, a VNT turbo needs to be electronically controlled to do it right. The "complex" mechanical linkages that some have used are a good compromise but definitely not ideal for every situation.

[jimfoo]

Certainly less complex than having to put in a TPS, speed sensor and all the other associated electronics. I got an IDI to get away from all that stuff. Need to change a  setting, just change a spring, or preload, or the length of an arm. Don't knock it till you've tried it.  :twisted:

[rabbitman]

Hey Andrew, I might have missed it but do your vanes open at idle?

[jtanguay]

DEAR LORD WHATS WRONG WITH YOUR PIC ANDREW!!!!!!!!!  :shock:  :shock:  :shock:  :shock:  :shock:  :shock:  :shock:  :shock:  :shock:  :shock:  :shock:
/hijack

[giulianot]

It's as simple as I could come up with without any drivability issues.  Because the setting of the vanes does not correspond to specific boost pressures (like a wastegate), but rather the rate of boost increase, if just a wastegate actuator is used to push the vanes open, you will have a very jumpy car at higher rpm transitions from cruise to acceleration.

Another criteria I was opting for was to have the vanes open at idle and open as much as possible at cruise in order for better engine efficiency.  With simply a wastegate actuator on the vanes, the vanes will be in a closed position at idle and cruise with resultant increased backpressure, etc.

The third criteria was for a system that would fail to a safe mode.  A wastegate actuator attached to the vanes will close the vanes (regardless of rpm) if you end up with a boost leak.  That can overclock the turbo.
It would be significantly more complicated IMO to work out a circuit to control the vanes like the stock unit.  You would need an accelerator sensor, rpm sensor and boost sensor and create a map to correspond to the various situations.  If it is simple for you to do, then by all means please come up with a simpler control that is as effective, so I can use it on my next one.    :wink:  If a control system was created that was as effective, easier to install and overall simpler, I would be a repeat customer.

Andrew

I think we have the knowledge and the resources here to build a stand alone vnt controller.  I would start with all my inputs needed,  
1)a potentiometer for the tps
2) A 3 BAR MAP or some type of pressure sensor
3) temp sensor to monitor engine temp
4) engine RPM's  from the alternator w
5) ?

Then choose a CPUmaybe a motorla 68hc11  or a PIC any 8- 16 bit micro controller will do. Nows the tricky part, finding someone who can write the program . The map and be stolen from vag-com'ing  any tdi for base line maps to extrapolating the algorithms need for the program.  Then make some graphs with a chiped tdi  :wink: Granted thats a lot of data logging and math but again all possible with the right help.

Last would be a PWM signal output from the CPU to the N75 valve to contol the VNT actuator. The vacume could be provided from the vacume pump for the brake booster.


There is definatly a demand for a standalone VNT controller so why not try to make one

[lyeinyoureye]

An op-amp would be wicked simple, but I have a feeling it would require calibration in most cases. The nice thing about a programmed microchip is, provided it had feedback in the form of boost, it would pretty much be plug and chug once someone wrote the code w/ the appropriate inputs, and I imagine we could even have different driving modes.

[jimbote]

FWIW, just a simple wire to the vanes that corresponds to throttle lever position is a more drivable setup than just a wastegate can IMO, but you don't end up with any control over the max boost.

Andrew

maybe a simple wire in conjunction with an external wastegate plumbed to the egr port to control max boost?...(maybe someone already said this?)

[Vincent Waldon]

Very very cool Andrew.... there's definitely a controller of some kind there.. might just be for the stepper motor but perhaps it's even smarter.  Might be tough to reverse engineer the position curves it's mapped to, but you never know.

5 leads sounds like power, ground, vac sensor, throttle sensor, .  Did a bit of googling but didn't find any schematics... you probably already have an engineer lined up but if not happy to help wherever I can.