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+--- Thread: VNT control (/showthread.php?tid=24169)
VNT control - 205steve - 21-05-2014
Hi all,
Si how are people controlling any VNT that they may have fitted?
apart from the arduino that ive read about from a well known member on here, what other ways are there to control one?
RE: VNT control - Ruan - 21-05-2014
Flip boost can upside down and put on actuator, but there are serious disadvantages to this as the vanes are permanently in the maximum boost position until up to pressure, cruising this causes high exhaust manifold pressure and high inlet pressure - not good for the engine, things do get hot if cruising and you need to be wary of EGT doing so.
Other than that, you've not got many options, there's people who have tried springs, actuators, shims, cables to make some sort of "mechanical" solution, but always ends up being a total bodge and never working right - remember every single time you adjusted fuel or wanted slightly more boost, you've got to change ALL the springs, shims, spring preload etc for a 1psi gain in boost... Nightmare.. PLD/Arduino really IMHO these days is the only way to go for a car you actually drive and be reliable as hell
RE: VNT control - 205steve - 22-05-2014
Thanks ruan, sorry to sound daft but what are you calling the "boost can" please?
so to get good results and drivability i need to be looking for a PLD or a Arduino to get the boost control nailed.
RE: VNT control - zx_volcane - 22-05-2014
Boost can / boost actuator - like you would find on a normal wastegated turbo.
Older vnts have a vacuum actuator, the modern vnts have electronic actuators.
I wouldn't go back to a boost can / mbc setup on a vnt now - but for a quick and easy setup its ok, as long as you can factor in for a spare turbo, maybe not essential, but I like to err on the side of caution.
Cruising though really isn' the one, so if you do any amount of motorway miles you're going to have to put up with stupid high emp, inlet pressure, heat and a dip in mpg, all whilst continuously wringing the vnts neck.
Electronic vnt control really is amazing once its all figured out. Having complete mappable control and feedback is superb.
RE: VNT control - 205steve - 22-05-2014
Thanks, so for it to be "correctly"controlled i need to get myself a controller or stick to the gt17 i have with the traditional wastegate for boost control
RE: VNT control - zx_volcane - 22-05-2014
Up to you matey
The internet will generally get a bit technical - no harm in throwing it on with an mbc and just drashing on till it breaks.
RE: VNT control - 205steve - 22-05-2014
mmm i dont like breaking things lol.
I need to do a bit of reasearch and look into it a little better, ive seen you name pop up a few time too lol ;0)
Im an electrician by trade so wiring isnt a problem, i have also worked on standalone systems before but full systems like mbe.
RE: VNT control - zx_volcane - 22-05-2014
Not great when things break, but its the spirit of all things xud
throw a rod, lift a head, bin a turbo - all fun and games
maybe grab an arduino and get familiar with it, bit o breadboard, some simple control circuits, little touch of programming and see how you get on.
RE: VNT control - sweeney1987 - 22-05-2014
Is it possible to control an older vacuum type turbo with the arduino setup then?
RE: VNT control - 205steve - 23-05-2014
i suppose you would activate a bcs which is controlled by the arduino
RE: VNT control - Dave - 23-05-2014
You can run a vnt in quite a relaxed state which means you're not on the vane stops all the time, but you loose alot of response/spool down low. It would definitely have its advantages over a wastegate turbo, but you're going to loose 50% of the advantages a VNT will offer you over a standard wastegate turbo if you do run them in the relaxed state, but as said above to get the advantages of a vnt spool you need to run things hot/poor mpg/high emp/imp etc
RE: VNT control - silverzx - 23-05-2014
Boost can cant be that bad. It seems to be Darrens choice method of installation.
RE: VNT control - Danny Wideboy - 23-05-2014
What about toms VNT 205 with boost can? Went frighteningly fast.
RE: VNT control - zx_volcane - 23-05-2014
Ruan essentially outlined everything in his post
Will work fine with an mbc, but comes with drawbacks
RE: VNT control - Danny Wideboy - 23-05-2014
Ah, I see.
So it is a compromise to run like that, although in practice it may be fine, but as a daily, to drive to drive around as a shopping trolley, you may damage the engine by the vanes being closed too often at too high revs, and not much adjustment to being open or closed?
RE: VNT control - darrenjlobb - 24-05-2014
If all your building is a motor for performance, a boost can is fine, a boost can will always give you max boost / power... as its always looking for "target boost"...the only real downside is the fact that "on cruise" its also still looking for "target boost" so the vanes will be more closed than they "need" to be to maintain enough power at that speed, IE its making more boost than it needs to burn the fuel, so yes, under cruise, you will be running the turbo a bit harder than you need to / wearing it out...however, My audi / car / toms 205 / many other cars ive setup / helped setup are setup this way, and tbh, ive not had a problem. both my car and the audi return fantastic MPG , drive like an absulute hoot, and all still have healthy engines, well my car is no more, but you know what i mean.
In an ideal world, mappable control is a better way fowards, but for the average person at home, and a 500 quid peugeot 306, matter of the fact is if your upgrading the blower you are only really generally looking for power, in which case this really is the easiest / most reliable way fowards for most people IMO.
RE: VNT control - 205steve - 24-05-2014
Thanks darren....i sent you a friend request on fb too dude!
(steve hancock)
RE: VNT control - MarkHam - 26-05-2014
(21-05-2014, 09:52 PM)Ruan Wrote: Flip boost can upside down and put on actuator, but there are serious disadvantages to this as the vanes are permanently in the maximum boost position until up to pressure, cruising this causes high exhaust manifold pressure and high inlet pressure - not good for the engine, things do get hot if cruising and you need to be wary of EGT doing so.
Other than that, you've not got many options, there's people who have tried springs, actuators, shims, cables to make some sort of "mechanical" solution, but always ends up being a total bodge and never working right - remember every single time you adjusted fuel or wanted slightly more boost, you've got to change ALL the springs, shims, spring preload etc for a 1psi gain in boost... Nightmare.. PLD/Arduino really IMHO these days is the only way to go for a car you actually drive and be reliable as hell
Why do you flip the boost can upside down?
RE: VNT control - anto - 26-05-2014
Most of them work off a vacuum. I think they mean to open the can and turn the innards around so itl work off boost.
RE: VNT control - 205steve - 26-05-2014
ive found a pressure actuator from an old turbo off of my 300tdi landrover which im fitting to my vnt, i just need to work out which position i need the actuator to hold the vanes at next