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VGT Discussion on turbos

alansupra94

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Well I am very interested in running a VGT turbocharger. From what I have read the technology is great and amazing. The problem is controlling the VGT properly in Holsets are not easy.

I have an AEM so I have quite a bit if flexibility. I would like to know the best way to control it. Curtis mentioned that the idea of using a wastegate actuator isn't the best.

Discuss.
 

AnotherNewb

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My curiosity raises the question 'what mode of operation will keep the turbo in its peak operating range?' I asked this in curtisis thread. Should it be load based, rpm based, boost based? I can understand why using a wg acuator wouldn't efficient since it would go from closed to open instantly and not hold the veins(?) in any in between positions. Since this is truck tech I am going to assume that the factory controller is 24v. Unfortunatly I feel that the motor on the tubo from the factory would be the safest most efficient way to control it since it was built for the heat of the turbo. So I pose this: since its just a simple stepper motor, albeit 24v, wouldn't it be fairly simple to control it with somehing similar to the exhaust cut out controler similar to one that was for sale here? To me it would make sense to base the opening and closing of the veins on throttle and rpm inputs then fine tune the response for performance.
 

alansupra94

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There was a thread regarding how the controller works. Apparently it was a CAN communication.

I will let Curtis chime in since he seems to know more.
 

curtis

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I'll respond in a few hours.....It's sushi time. /ubbthreads/images/graemlins/grin.gif
 

curtis

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Ok where to begin I guess first is wow the sushi was fabtabulos. /ubbthreads/images/graemlins/grin.gif

Ok now to VGT's
Only a few people have put these on gas engines of the 4 cylinder size I've found. Aero (his sign on name) on the homemade turbo site and the dsm sites and dany250r has as well. His is the 1G on you tube with the sick sounding turbo scream that sounds like a turbine engine on a fighter jet. Aero say ransient responce in 4th gear go from full vacuum to +15psi in .9 seconds so instantaneous boost is possible

These aren't for the non fabricators because its going to be alot to make one work. I have to use one of these its just in me to do it. There large 65 lb shipping weight large. This will require not only the lose of your AC on a galant but moving the radiator forward and more than likely a custom header out of schedule 40 not sch 10 and some type of support structure under the turbo. Aero made an adapter using a 2G manifold on his and is running a 2.3 but with stock head, cams and intake and is getting silly spool up like GT28 time out of a huge frame turbo which without the vgt would never be possible. Not dogging on there setups but they used a 14b actuator to control the disk that houses the vanes. In my opinion this is the wrong answer and a bandaid to make it work so so. If you stop the action and think about whats going on you can realize why.

Lets do drag racing.

Pull to the line candles drop and you go. When you first release the clutch and hit the gas the engine is at vacuum then goes to boost fast because of the load on the system. This part is fine except you can't limit the amount of movement of the vanes. Closed is .14 and open is 1.85 ar. When you launch depending on weight of car and all other mods you may want a max of .82 or .63 in first but with an actuator your going to see 7psi of boost then the vanes are going to 1.85 almost instantly, this will slow the spool time dramatically. Then as you shift a stick car your engine sees a few milliseconds of vacuum which is going to slam the actuator and vanes to .14 and over speed the wheel. It needs to be limited to lets say .48 on the 1/2 shift. Then as you go up in gears you'll bring up the closed ar and open up the full open so the monster can flow. Have to remember the compressor map on the He351ve goes up to 4.2 bar and is really really wide and thick. Total area of the full efficiency is about 5 or 6 times the area of a GT35r so when done correctly will flow like a GT40/42 and spool like a 28. These have cast ti compressors and and can take the abuse and I'm guessing the compressor ar is up in the .80 to .90 range. So fourth gear will come on with all the supporting mods like a freight train. I really believe that with the correct fuel and supporting mods this thing could put a VR4 in the high 9's low 10 rather easily after the controller is sorted out. Have to remember these flow up at around 70 to 75 lbs a minute.


Now for more controller info.

When done you need to have a start up and shut down sweep like the factory did but I think even more since these coked up on a diesel. Maybe as the key is turned the controller tells the vanes to open close 5 or 8 times. Then at shutdown the controller needs to sweep back and forth the same after the wheel stops spinning. Not hard to know because these have a built in rpm sensor from the factory.

As for driving I'm thinking this needs to be not only a rpm but a load based system. Lots of yes /no fuzzy logic intel. Everyones car is going to be different. From wastegates to injectors and flow characteristics of the heads etc. So everyone should have full control and have different buttons for different maps you set up like an afc bar graph and be done from a 500 rpm to 12K in hundred increments. One map for gas mileage 1.0 to 1.85 only, one for road racing short track, road racing long track, drag racing, in town driving, street racing from a kick. Thats where 800 hp cars run 13.5's in the 1/4 smoking all 4's /ubbthreads/images/graemlins/rofl.gif List can go on and on and altitude /mtn driving will effect this as well so this needs to be a fluid system and easily adaptable not just a straight up heres what you get controller.

I haven't read up on these in a while but have watched a few you tube video's on the subject and know megasquirt now has a version with a can bus. /ubbthreads/images/graemlins/dunno.gif Need to call them to see whats up. If it comes that our resources around here can't make it happen I may sell my mega squirt and get a new one and get this one with 8 injector drivers. Right now I have 4 1250's and a bunch of methanol nozzles to play with and really don't think that will do this turbo and my set-up justice at above 7K and boost past 30psi.

For you guys that are interested in this keep the links and discussion going and I'm sure we can make this happen. I'm no spark chaser and never claimed to be but I've spent countless hours over the last few years thinking about what and when the thing needs to change placement and why but never liked electronic stuff that's what work orders are for. You see a problem and pass the buck to someone that is school trained for it. The link above is what I mean those guys are so talking above my head on some of the stuff.

Another few things I've thought of that would be cool to incorporate is a knock sensor if you see marginal knock it will open up larger to lower temps and releave back pressure while in lower gears, still haven't thought that all the way out.
micro switch halo ring around the shifter so the controller knows what gear your in.
With the halo ring it could be set up to go full open on a missed shift also could be set up for missed shifts turns off other things like nitrous solenoids etc.

Like I said understand what needs to happen but just not an electrician.

Ok to much sushi have to go.

But first listen to this click me

And just found this click me for a vr4 WITH ONE OF THESE! Who is this guy
 

Rausch

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Cleveland, OH
This intrigues me. /ubbthreads/images/graemlins/smile.gif

Rather than a more complex load based system, why not simply use what you already have to work with? Wheel speed.

I would think a stepper motor, or linear actuator (something with fast actuation) and a 'controller' that reads/interprets wheel speed and makes A/R adjustments to suit would be all you need. Maybe a full open switch for those highway cruises...

If you can pin down a reasonable, efficient max wheel speed, and continually adjust the A/R to maintain that speed, you should be able to get virtually all the benefits offered by the VGT setup, no?

Think about it this way: low rev/low load- A/R is at it's minimum. As load, and wheel speed increases, the actuator moves the vanes to keep the wheel speed where you want it. Load drops: Say between shifts, and the system shrinks the A/R until that wheel speed is recovered.

I don't really know prep about programming and chips/circuit design for motor/actuator driving, but I'd think that would work quite well. No idea how to really build that part though /ubbthreads/images/graemlins/frown.gif
 

AnotherNewb

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I'm fairly new to ecmlink but couldn't you use the boost control inside of link to control a wg actuator and control the vgt? Kinda like adapting a cyclone manifold.
 

curtis

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With the actuator and boost controller your still dependent on pressure and its only concerned with regulating up top boost not the state when off boost. Oh thats something else I meant to type. Lets say you just ran a bike on the interstate top of 4th gear and lifted you don't want the vanes to close off because your at 145mph and at 9K and when it sees vacuum on an actuator based setup your going to close it off to .14 and essentially turned the turbo into a jake brake.
 

curtis

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As for Aaron's idea I like it but I'm like him finding a linear actuator strong enough to hold the vanes in place with heated gasses and 2.0 liters of fuel injected furry pushing against it. But the idea is solid and being load based with a dial to control it you could limit the ar to what ever you want it to open and close to but adding in the different gear requirement will need some type of logic chip I'm sure.
 

curtis

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This is what happens during a over speed situation. watch video
 

GVR-4

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Asheville, NC USA
Just FYI, Garrett calls theirs VNT (variable nozzle turbine) and BorgWarner calls theirs VGT (variable geometry turbine). Sorry if this has been repeated, but I interned at BW 5 or so years ago, so I thought I would share what little I know. BW had both vacuum actuators (like a wastegate actuator) and some "smart" actuators made by Delphi at that time that interfaced with the ecu, depending on the model. As some of you probably know, the BW VGT is used on the Porsche 911 twin turbo (presumably) with success. I would look at how they use it. Most likely with some fairly complex control system to get the most benefit from the design.
 

AnotherNewb

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Quoting curtis:
This is what happens during a over speed situation. watch video



Wow, one more reason not to buy chinabay!!!

How about this:
A controller that uses throttle position, rpm, and manifold pressure. Make the system so it is always open at zero throttle with a jakebrake switch to overide it. That way when you lift off it still stays open. Then using rpm and tps imputs the controller will have the ability to adjust the collars movement and speed. Hang on, ill brb.
 

AnotherNewb

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I'm back... Switched from phone to laptop.

I have one of these:
k8055_big.jpg


Its a Velleman k8055 USB Interface Board

What it does is gives you 5 digital inputs and 2 analoge outputs with PWM. Through the USB cable you can write a c++ program to control the outputs based off the inputs on the board. I got it as a christmas gift and assembled it, then I didn't know sh*t about programing. I bought this huge book and haven't read a page.

I said all of that to offer this up: I will give my board and giant book to anyone that has a VGT turbo that wants to attempt to use this to control it. If someone is interested, drop me a PM.
 

BrandonEchols

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Jan 18, 2010
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Quoting curtis:
And just found this click me for a vr4 WITH ONE OF THESE! Who is this guy



That's chevyracer5613's car, his introduction and build thread can be found HERE

I have a huge interest in this controller.
I have two of these turbos sitting in my garage right now, one is Paul's, but the other will eventually be going on 477, and I'd really like it if the controller issue was sorted by then.
Unfortunately, I have no C++ experience, and know nothing about the CAN bus, so I'm just waiting on some other, smarter guys to figure it out.
 
Last edited:

DynastyLCD

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May 12, 2006
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Harwinton, CT
curtis, i cant tell you much about the holset VGT, but the Garrett VGT found on the 6.0 diesel is a different story. those use a stepper motor to control the vanes directly. the determining factor for the position of the vanes was between EBP (Exhaust Back Presssure) sensor, and MAP sensor. i cant remember exactly but TPS might have played into it as well. the computer then would sort out all this data and activate the stepper motor as it saw fit. the EBP was the primary sensor for this system though. so if you could make a system to read and incorporate data from an EBP sensor, a MAP, and TPS, you could have its output be to control the vanes. then, in theory, you wouldnt really have any need to tune it as it would handle everything itself - with no fears of overspeeding.
 

curtis

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I forgot about this little deal but bought it with a lot of stuff on ebay. Some engineering firm had this box the 150 meth pump, bag of nozzles, the older style cooling mist in car controller and the high speed valve that takes the pulse out of the system with a starting bid of 250. I sent the guy an email and ask if he had a buy it now price I figured he would say 750 or so. He came back and said he didn't have time really for ebay but would take 250 shipped right now so I jumped on it.


Everytime I try and open the pdf the system locks up and or crashes so if your computer hates pdf don't hit the link. If your system will open it do a copy and paste and send me a pm or just post it here. This little box may work for what we need it for.

cooling mist smart injection click me
 

alansupra94

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Wayne,NJ
I would assume that I would be all set programming wise since I have an AEM EMS. I would just have to use the nitrous tables that they have. Interesting.....I have no idea how a stepper motor works so I will have to look into that.
 

DynastyLCD

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May 12, 2006
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alan, an iac is a stepper motor. basically, as you adjust the applied voltage, its physically moving in or out. same with the Garrett VGT vane adjustment. theres a stepper motor that moves forward or backwards to let the plate that holds the vanes either push them open or closed. its pretty simple.
 

BrandonEchols

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Jan 18, 2010
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Anchorage, AK
Quoting curtis:
Everytime I try and open the pdf the system locks up and or crashes so if your computer hates pdf don't hit the link. If your system will open it do a copy and paste and send me a pm or just post it here. This little box may work for what we need it for.

cooling mist smart injection click me



PM Sent.
 
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