VNT

[rixy]

wat is one?? i've heard lots of talk about them, wanna know what it is??

Variable something turbo maybe?? ha ha? just a guess??

[rixy]

variable NOZZLE turbo.....just been scouring google etc, to learn exactly what one does :-)

So.....on an IDI gtd engine, if i was running a VNT, would the standard pump be up to the job? How would the pump know to put more fuel in earlier on in the revs?? is this due to the LDA???

[the caveman]

It's a type of turbo that doesn't use a typical wastegate. The boost is controlled somewhat internally instead. If you look for the avatar for cyrus#1 you will see how the internal vanes move. Unfortunately there isn't an easy solution to control it without having some kind of processor . Dig around here on this site about using one. They are fantastic for smooth boost if you can get one to work

[jtanguay]

http://vwdiesel.net/phpBB/viewtopic.php?t=11628&postdays=0&postorder=asc&start=30

you have quite a bit of reading to do  :wink:

here is the video of the linkage movement with engine off

as you can see, the linkage can be adjusted quite easily to give more boost or less boost, depending on what you want.  and you don't need a VAGCOM  :lol:

here you can see the linkage in action.

this system works by using the accelerator cable to close the vanes.  once the desired boost pressure is reached, the boost can starts to open the vanes just like a wastegate will open the dump valve.  very ingenius.

both above video's are courtesy of Tintin.

[the caveman]

See, someone with more patience and wisdom [than me] can make it work. Personally i am relived and happy about it.

[jtanguay]

An LDA pump will automatically increase fueling according to boost pressure.  It will do so regardless of turbo type and when it spools.

Andrew

and the beauty of the mechanically controlled VNT turbo, is that you don't really need an LDA, so it is the perfect candidate for N/A conversions.  

best to probably increase fueling in 1/4 turns and take for a test drive after each turn, to get an idea of smoke, and or EGT's.