***feeler***control your vnt yourself

Eivind

Member
Joined
Aug 8, 2012
Location
Norway, Europe
TDI
'00 Audi A4 1.9 TDI Avant quattro, '04 Audi A4 1.9 TDI Avant quattro
Well I finally got this actuator dialed in. Maybe I will post a new video. Working very good now, milage is better than ever, I have all the power the setup can produce and egts are typical for the setup, which is to say low. I can guarantee It will operate just like factory.

Now I have it adjusted so my cruise is between 0 and 5 psi, max boost is about 22 psi. Milage averages 50 mpg both city and highway combined. Car revs great and boost response is plenty fast. I checked the vane lever and I can flick it with my finger it's so free and smooth. Egts around town are 200 to 600 degrees and 75 mph highway is about 800 degrees. If I want more turbo boost I have up to 3 ways to get it with simple adjustments. Now I believe I have the boost creep issue resolved as well:)

So if anyone wants to test this out just message me.
Sounds amazing! How does it respond if you're cruising along (say 50mph, top gear) and then floor it? What would you think would be the setup process, timewize, if you were to convert another turbo?
Do you think this gives the same performance figures as computer controlled (with the same max boost - Cool if someone could compare graphs on a stock engine), giving full boost just as early?

Hope these questions aren't inappropriate. Would be cool to see another video!
 

madcowintucson

Veteran Member
Joined
Oct 3, 2009
Location
arizona
TDI
golf
Sounds amazing! How does it respond if you're cruising along (say 50mph, top gear) and then floor it? What would you think would be the setup process, timewize, if you were to convert another turbo?
Do you think this gives the same performance figures as computer controlled (with the same max boost - Cool if someone could compare graphs on a stock engine), giving full boost just as early?
Hope these questions aren't inappropriate. Would be cool to see another video!
Yes I intend to post another video. No you are good its not inappropriate at all I am glad to see the enthusiasm!
Full boost is just as early as a vaccum setup. It's really dictated by vane position it has nothing to do with the type of actuator. With that being said, sticking vanes or a weak/bad actuator can create lag or overboost. My vanes where always sticking in one position or another. So why spend money to replace weak/bad actuator and anything else that could be going on when I a more robust proven method is available.
I am not sure what you mean to convert to another turbo or what time is involved. If you mean a turbo other than a vacuum operated turbo or such as a jeep liberty turbo etc, I would have to have the turbo in front If me to study it and make the modifications. There would be adjusting once it was installed on the vehicle. It took me several times to adjust this to where it is now, but once it's done then it would be repeatable just as anything else.
If I was cruising in top gear at 50mph that would put me around 1500 rpms and I would not floor the car at all, with that being said, it you were already pumping 10 psi then the turbo would immediately respond to max pressure, but I feel doing so like that egts would rise and be inacceptable not because of the turbo but because the rpm is mismatched to speed. With that being said, if you floor it at say 2000 rpm it will hit max boost and stay there as rpms climb:D
 

Lensdude_com

Veteran Member
Joined
Oct 31, 2004
Location
Edmonton, AB
TDI
99.5 MK4 Jetta (ALH) "Betty" (sold), 2005 MK4 Jetta (BEW) "Stinky-Pete"
I think if you design this around the PnP principle then it will certainly increase your customer base...
contain all the valving inside a black box with barbed ends protruding and pre-cut vac hoses, connectors, clamps and pictorial instructions to mitigate translation errors...
I would buy one like that :)
 

madcowintucson

Veteran Member
Joined
Oct 3, 2009
Location
arizona
TDI
golf
I think if you design this around the PnP principle then it will certainly increase your customer base...
contain all the valving inside a black box with barbed ends protruding and pre-cut vac hoses, connectors, clamps and pictorial instructions to mitigate translation errors...
I would buy one like that :)

Well actually, there is nothing like that, it is all self contained, simple as can be.
 

Lensdude_com

Veteran Member
Joined
Oct 31, 2004
Location
Edmonton, AB
TDI
99.5 MK4 Jetta (ALH) "Betty" (sold), 2005 MK4 Jetta (BEW) "Stinky-Pete"
Well actually, there is nothing like that, it is all self contained, simple as can be.
...seriously though, chrome the black box and charge Audi guys double for it :D
I suppose the difference is whether you want to be the guy who came up with a gizmo or the guy who brought a product to market :)
 

madcowintucson

Veteran Member
Joined
Oct 3, 2009
Location
arizona
TDI
golf
...seriously though, chrome the black box and charge Audi guys double for it :D
I suppose the difference is whether you want to be the guy who came up with a gizmo or the guy who brought a product to market :)

lmao so a little false advertising to the Audi and porche guys and triple the price lol. yeah I can sell them an empty black box completely sealed with epoxy and just stick in some hose nipples and a usb port and some wires hahahaha. Well right now its just a hobby, so I suppose i wont be either.

I am just the guy who made something work when I felt a need existed. I mean, I wanted my vnt cake and eat it too lol
 

Lensdude_com

Veteran Member
Joined
Oct 31, 2004
Location
Edmonton, AB
TDI
99.5 MK4 Jetta (ALH) "Betty" (sold), 2005 MK4 Jetta (BEW) "Stinky-Pete"
lmao so a little false advertising to the Audi and porche guys and triple the price lol. yeah I can sell them an empty black box completely sealed with epoxy and just stick in some hose nipples and a usb port and some wires hahahaha. Well right now its just a hobby, so I suppose i wont be either.

I am just the guy who made something work when I felt a need existed. I mean, I wanted my vnt cake and eat it too lol
If this is a unique design that serves a useful purpose then you should apply for a US patent...
even if you don't have the gumption to take a product to market you might be able to scare up a venture capitalist to front the whole deal...
or sell the design to a supplier of aftermarket parts.

I became interested in this project of yours because I want to preserve the health of my KP-39 without having to bird-dog the tach all the time...
 
Last edited:

madcowintucson

Veteran Member
Joined
Oct 3, 2009
Location
arizona
TDI
golf
If this is a unique design that serves a useful purpose then you should apply for a US patent...
even if you don't have the gumption to take a product to market you might be able to scare up a venture capitalist to front the whole deal...
or sell the design to a supplier of aftermarket parts.

I became interested in this project of yours because I want to preserve the health of my KP-39 without having to bird-dog the tach all the time...
I don't know what you mean to bird-dog the tach, but if its a vacuum operated vnt with a standard mount actuator then this will do. As my car is running, its just a nice smooth linear boost curve that tops out at about 22 psi. Also this will make sure the vanes wont stick in one position or another as every time I hit 22 psi it is because the actuator is moving the vanes through their full range of motion as opposed to reaching 22 psi because of stuck/sticking vanes. Trust me, my vanes were so stuck I couldn't even move them with my hand, I had to use a screwdriver to leverage them through the carbon buildup. I had my hand under the hood almost every day messing around with the vanes to try and free them up after driving by connecting and then disconnecting vacuum while I pushed and pulled and stuff:eek::mad:. So no more need for Italian tuneups as regular daily driving will suffice!

Unfortunately this is not a unique design. I got into this because I saw a need and a gap and I couldn't afford the time or money to figure out why mine wasn't working like it should. I already have a way to control the n75 valve and make any boost curve I want through software based on tps, boost etc. with an external controller, but it is very expensive and I believed I could do the same thing without all that. By the way, the frequency of the N75 is 300Hz just to clear up any confusion. That's really fast, no controller I have seen can run a solenoid that fast and whomever is building external controllers should know that. The solution is to swap out the N75 to run a standard 60Hz solenoid just like regular EBC's. Or as an alternative, run a gas vw 1.8t N75 and allow the computer to control that as it relates to boost, but you still will need the appropriate pressure based actuator. Why a vacuum system was chosen is beyond me!

Truth be told my uncle convinced me that I should try and do a feeler because it was so simple and worked so well so I did lol.

If I built a racing engine and controlled boost like I am now, and people saw, they would ask me how I did it and if I would sell it to them. If I put a vnt turbo on a gas engine or a non computer controlled engine and swapped it into another vehicle, people would want to know how I controlled boost and if I was going to sell anything.

Dont get me wrong, I am absolutely all for PD and common rail engines. However, I had one of these engines, I would still swap over if nothing else just for simplicity, peace of mind, reliability, cost, and performance and mileage.

I know when anyone figures out how simple it really is, they will just copy it, however, its still going to cost them the same or more than just buying something from me if I was a vendor. Then there are some people who just want something the can bolt on and go and are willing to pay a little for the convenience of having the work done for them.

Once I had limp mode deleted from my ecu, it became a whole lot easier to experiment to where I am now. It still took me a lot of time and work to figure this out and truthfully, as it sits, I wouldn't ever trigger limp mode again. But that is the whole point, if the tuner is tuning the engine and they are telling the computer where the requested boost should be based on various parameters and you don't know what that requested is then therein lies the problem. So if your tuner tells the engine to request 5 psi at X load, say driving on the highway, but you are producing X more or less than requested, computer enters limp mode. Essentially, you would have to tell the tuner what it is you want before you even know and then ask them to program that in as requested. When towing my 1800 lb trailer I was always running less than 7 psi at 55 mph and I couldn't even trigger my water/meth injection until l 10 psi. How lame, I would have felt more comfortable running 10 to 15 psi and running the water/meth injection at a steady state rather then intermittently. But I cant tell my tuner that and there is no way anyone would spend the time to reprogram the ECU for different requested boost so a guy can experiment. The way mine works if if I was towing that same trailer now, I would be at that 10 to 15 psi, but I would have always triggered limp mode, now I don't and I can run my water/meth at a constant rate as oppossed to only when I try to accelerate. Ok I got off topic haha.

I know if there is enough interest I can make a deal with the manufacture to buy and modify and sell under my name their actuator, IF there is enough interest. I would get the price down around $200 for the end user after I do all the work to modify it. That's as much as you would pay right now for an unmodified actuator and then you figure it out on your own.

Hope that helps and if you know the boost limit of the KP-39 you can set this up and hit that limit all day long without exceeding it. So if you want 10 psi or 15 or 20 or 30 or whatever it can be done, no spikes, no lag just smooth and flat and no drop off at high rpm. I can't make it drop off at high rpm I don't know what that's all about. Hope I cold help.
 

madcowintucson

Veteran Member
Joined
Oct 3, 2009
Location
arizona
TDI
golf
Ok just checked out KP-39, yes this will bolt right on. Looks like an M6x1.0 thread to the lever so instead of the garret connecting I actually like this way better as it would be super easy to build and adjust once its in the car. Rod length stays constant, but loosen the nuts and slide lever back and forth to achieve desired results, very easy!
 

Digital Corpus

Top Post Dawg
Joined
Mar 14, 2008
Location
Ontario, California
TDI
'97 B4 w/ 236K mi body, 46K mi soul
300 Hz is slow. The micro I'm using for other things can do 938 KHz. A little google search gives me info saying Arduino can do ~61 KHz.
 

madcowintucson

Veteran Member
Joined
Oct 3, 2009
Location
arizona
TDI
golf
300 Hz is slow. The micro I'm using for other things can do 938 KHz. A little google search gives me info saying Arduino can do ~61 KHz.
Lol yeah I am not saying there is not pwm switching. Wonder what the switching current is? 40 amps?

Anyways, my point is that if you want to control the actuator even with vaccum it can be done with off the shelf parts. It's still going to be expensive though.

I have been controlling my water/meth pump this way for years, I can vary the frequency and duty cycle. The pumps run at 30Hz so all I do is graph out a boost curve and set the cycles to 30Hz.

Same thing can be done for wastegate control or vnt control, just set the Hz to 60 and hook up the solenoid and adjust the target curve in the software.

But either way I don't trust the actuator itself, to expensive to replace, not very good build quality and if mine was bad there was no way I could even tell by testing it wasting a ton of time in guesswork and possible misdiagnosis.

In the software you can draw a boost curve but you can't taper off boost based on rpm. What you are in reality doing is drawing an inflated boost in the mid rage or whatever and then tapering it back to the max sustained boost. This gives the illusion of boost taper at higher rpm, buts really not.

Anyways I think boost based on tps% is the way to go without adding complexity to create a map, but If my setup works great with no computers why introduce another variable.
 

vanbcguy

Veteran Member
Joined
Feb 22, 2013
Location
Vancouver, BC
TDI
'93 Passat - AHU mTDI with GTB1756VK
I've been using GM solenoids for my controller - they basically go binary much over 30Hz though. The solenoids are super common and only about $20 plus you can find them just about anywhere in North America.

The only trick with the Arduino is it only has a few possible PWM frequencies. There's 3 system timers that control the PWM pins and one of them is also used for all the delay loops so if you change it you mess up any time based things in your code. The remaining two control 2 PWM pins each. One has 5 available frequency steps, the other has 7. 30Hz is the lowest step available, then 120Hz, 480Hz, etc. At 120Hz my solenoids barely have a useful range between fully open and fully closed so not much good for controlling boost. 480Hz just turns them in to tiny musical instruments. 30Hz it is!

The code base I'm using has 2D maps so I definitely can adjust boost based on RPM as well as TPS. I have an EMP sensor too so I've been considering adding a map to limit VNT position based on EMP. At the moment I've only coded it to show on the status display.
 

madcowintucson

Veteran Member
Joined
Oct 3, 2009
Location
arizona
TDI
golf
I've been using GM solenoids for my controller - they basically go binary much over 30Hz though. The solenoids are super common and only about $20 plus you can find them just about anywhere in North America.

The only trick with the Arduino is it only has a few possible PWM frequencies. There's 3 system timers that control the PWM pins and one of them is also used for all the delay loops so if you change it you mess up any time based things in your code. The remaining two control 2 PWM pins each. One has 5 available frequency steps, the other has 7. 30Hz is the lowest step available, then 120Hz, 480Hz, etc. At 120Hz my solenoids barely have a useful range between fully open and fully closed so not much good for controlling boost. 480Hz just turns them in to tiny musical instruments. 30Hz it is!

The code base I'm using has 2D maps so I definitely can adjust boost based on RPM as well as TPS. I have an EMP sensor too so I've been considering adding a map to limit VNT position based on EMP. At the moment I've only coded it to show on the status display.

Well the controller I bought I can select any frequency from 10 to 60 cycles, then I set my curve, so for example I choose 60 Hz then at no load I set the duty cycle so as to pull max vacuum to actuator, then as boost increases to my max set psi the duty cycle changes to compensate so as to not over boost. So basically we are only dealing with a curve, it could be smooth or abrupt, buts a curve. So say you want to hit 20 psi early, just keep duty cycle the same until 20 psi then open vanes by changing duty cycle to compensate. Then you can also change duty cycle anywhere in between to smooth it out based on pressure or tps%.

I just decided to skip all of that, if possible, and make its as simple and essentially self correcting as possible. Apparently I was sucessful, if you got on my car today you would never know there was no computer control over boost. It reacts fast enough, it hits the target psi at the right time so as to not over boost to early or to late, it has a nice curve, it doesn't fluctuate or do weird things, it's extremely consistent and I never have to worry about boost spikes etc.

I'll post posting another video soon. Best of all if I want to make a change I can do it myself at anytime, independently.
 

madcowintucson

Veteran Member
Joined
Oct 3, 2009
Location
arizona
TDI
golf
So I been running the wastegate based on boost pressure alone for awhile now. Works as intended and is totally predictable.

I ended up opening up the vanes on the turbo a bit farther to reduce boost in relationship to throttle. I decided to swap springs back to the 15 psi spring for now intill I get the intercooler installed. It hits 15 psi and stops dead in its tracks. I have way to much fuel going in right now so lots of black smoke but it works well. I will report back hopefully the intercooler will be installed this next month. Then I have to move my boost port to post intercooler and tune from there. I'll start with 15 psi and move up I can go up to 25 psi so on a vnt 17 that's plenty.
 

madcowintucson

Veteran Member
Joined
Oct 3, 2009
Location
arizona
TDI
golf
madcowintucson, what happend to this project?
I am interested in it.
Worked perfectly and no one was interested. Last time someone asked me about this it was a scam to get me to sell the the product on here without being a vendor in a poor attempt to get me banned from Tdi club. Other than that it works just fine and sold that car and project to a guy and he loved it. I only built that because my vnt vanes kept sticking no matter what I tried to do and this was the only way to get vnt without sticking vanes. Also I liked the idea of something I could control myself lol. Also it was just reliable and never overboosted at all. Just make sure you have a healthy intercooler to cool the charge because this can produce psi all the time if you want but you definitely need intercooling.
 

NoelMcC

Well-known member
Joined
Aug 2, 2015
Location
Calgary Canada
TDI
2005 Tdi Wagon; 81 Vanagon Subaru conversion.
So basically you have shelved the project. I’m interested in building one for myself, I’m an old tool and die maker so machining isn’t a problem. Could you share your design or are you keeping it locked up for prosperity ?
Regards
Noel
 
Top