we need an electrical wiz for a VNT - TDI Engine -General Info - VWDiesel.net The IDI, TDI, and mTDI source.

we need an electrical wiz for a VNT by the caveman on 14 Mar, 2008 15:55
Wouldn't it be possible to build a small processor to control a VNT on a mTDI? All it needs is inputs for rpm, boost pressure, possibly elevation and 1 or 2 other variables. Then the output for a n75. Does it exist already
and i don't know?
#1 by RabbitGTDguy on 14 Mar, 2008 16:30
There have been several threads on this topic and no definitive solutions and or answers. I remember a pricey solution just a few months ago...however, the power vs. cost of it just wouldn't float my boat in the least. I'd greatly consider a VNT if I could find or create such a controller and a turbo that will support what i'd like it too. I'm not a fan of the mechanical linkages complexity but haven't dove into it myself...

Would be a great DIY or product if someone could do it...I know of several that were looking at it...but I never saw anything come from it.

Joe
#2 by KTZed on 14 Mar, 2008 17:41
You could buy a megasquirt and probably use the boost control function built in or devise your own using the GPIO section of the board. This is just speculation on my part as I have not personally done this or even played with megasquirt at all but I do know that ppl use it to control boost electronically with a solenoid inline with the wastegate so theres no reason it couldnt be done with the VNT pot IMO. Cost about $150
#3 by lbreton on 15 Mar, 2008 08:25
Quote from: "the caveman"
Wouldn't it be possible to build a small processor to control a VNT on a mTDI? All it needs is inputs for rpm, boost pressure, possibly elevation and 1 or 2 other variables. Then the output for a n75. Does it exist already
and i don't know?

There is a controller design that works in the thread below. Not the first product listed in the thread. Read further down. It was created by user Ventil. It will cost you about 100.00 to build. It will do everything you need.

http://www.vwdiesel.net/phpBB/viewtopic.php?t=11793
#4 by RabbitGTDguy on 15 Mar, 2008 17:57
Apparently I did read far enough! That does look fairly simple. Now, to find it stateside here!

Joe
#5 by lbreton on 16 Mar, 2008 20:47
Quote from: "RabbitGTDguy"
Apparently I did read far enough! That does look fairly simple. Now, to find it stateside here!

Joe

I am going to build two of them next month. One for a friend (VNT15 on a 1.6TD) and one for my Cummins 5.9. I will be adding a TPS, so that will take a bit of experimenting.
#6 by RabbitGTDguy on 17 Mar, 2008 03:16
very nice...i'm trying to check on the parts availblity on this side of things...

Joe
#7 by KTZed on 17 Mar, 2008 08:17
Quote from: "lbreton"
Quote from: "RabbitGTDguy"
Apparently I did read far enough! That does look fairly simple. Now, to find it stateside here!

Joe

I am going to build two of them next month. One for a friend (VNT15 on a 1.6TD) and one for my Cummins 5.9. I will be adding a TPS, so that will take a bit of experimenting.

Keep in mind that the megasquirt boost control is made to work with a TPS and is tunable via a 6x6 table in the software. See these links...

http://www.e30tech.com/forum/showthread.php?s=7fe1ebeb867cf743c6684a264d796b20&t=30543

http://forums.turbobricks.com/showthread.php?t=80599

PS. This will allow you to set any boost level at any rpm and throttle angle which woudl allow you to run a big turbo without surging the compressor
#8 by lbreton on 17 Mar, 2008 12:30
Quote from: "KTZed"

Keep in mind that the megasquirt boost control is made to work with a TPS and is tunable via a 6x6 table in the software. See these links...

http://www.e30tech.com/forum/showthread.php?s=7fe1ebeb867cf743c6684a264d796b20&t=30543

http://forums.turbobricks.com/showthread.php?t=80599

PS. This will allow you to set any boost level at any rpm and throttle angle which woudl allow you to run a big turbo without surging the compressor

I only had time to do a quick skim through the article. That looks like an interesting option too. I know the mega squirt has a good solid reputation. What does it cost for the v3.0 board now days?
#9 by Bo Gunnar on 24 Mar, 2008 03:57
I have followed this discussion for some time now and have not seen a solution with an air valve that "inverts" the vacuum signal.
Function:
In normal position vacuum is connected to the VNT. This valve is controled by boost pressure via a boost control valve. When boost pressure reaches a set level the valve flipps over and vacuum signal is blocked and VNT is vented.
This kind of valve is shown on:
http://www.boschrexroth.com/pneumatics-catalog/content/AllPlatForms/Vornavigation/xMedia/en/pdf/PDF_p31034_en.pdf

Bo Gunnar
#10 by jimfoo on 24 Mar, 2008 04:51
I have a valve that has both a NO and NC port that I got at a pneumatic place for somewhere around $25. I think this is mine, or it is similar. I really don't see why you'd need a 5 way valve to control a VNT. A 3 should work.
#11 by fatmobile on 25 Mar, 2008 00:15
We'll have to figure a way to use a cruise control.
Hold the boost at a certain pressure, instead of a different speed.
#12 by Bo Gunnar on 30 Mar, 2008 02:41
Yes jimfoo, a 3-port valve should work. I just grabbed a picture I had. These valves are realy cheap, but does it work? Has anyone tested it?
#13 by jimfoo on 30 Mar, 2008 06:41
The valve I have seems to work fine, not that it is on anything at the moment.