VNT/VGT turbo appropriate for 3B? (1 Viewer)

[Mcreight911]

The one I use is from a merc sprinter
Comp wheel. 44.5 - 60
Turbine wheel 50 - 45
.50 ar turbine Housing
3rd gen Vnt, fullback turbine
Pretty handy turbo

Good for quick boost response but lacks outright turbine flow for big power .

 

[absalom]

What will you use to control the vanes? I only know of one standalone VNT controller...

 

[RufusTheDufus]

What will you use to control the vanes? I only know of one standalone VNT controller...

I'm designing my own controller.

There is a company in the UK that has a standalone VNT controller that's reasonably priced and should work well for boost control. There are a couple of open source Arduino-based systems out there too.

The system I'm working towards will use engine speed, TPS, intake MAP, EGT and exhaust manifold pressure initially. I may drop EMP if it turns out that it's not absolutely necessary. (I'd like to be able to do an exhaust brake with the VNT and think it may come in handy for that and other reasons.) In development I'll likely grab data on air intake temps (pre-compresor, post compressor and pre-intake to see how much the intercooler is helping.) I've got a scheme worked out to adjust the max fuel based on various inputs too. I've been working on this system for almost 3 years in bits and pieces and finally have the time and motivation to pull it all together.

 

[absalom]

I'm designing my own controller.

There is a company in the UK that has a standalone VNT controller that's reasonably priced and should work well for boost control. There are a couple of open source Arduino-based systems out there too.

The system I'm working towards will use engine speed, TPS, intake MAP, EGT and exhaust manifold pressure initially. I may drop EMP if it turns out that it's not absolutely necessary. (I'd like to be able to do an exhaust brake with the VNT and think it may come in handy for that and other reasons.) In development I'll likely grab data on air intake temps (pre-compresor, post compressor and pre-intake to see how much the intercooler is helping.) I've got a scheme worked out to adjust the max fuel based on various inputs too. I've been working on this system for almost 3 years in bits and pieces and finally have the time and motivation to pull it all together.

Well hurry up VNTs are my absolute favorite thing about TDIs

 

[RufusTheDufus]

It's my almost full-time job for the next few months. Going to start fabricating a batch of exhaust manifolds after the Holidays so I can test different turbos. I'll use Arduino Uno boards to do testing of the various circuits and collecting data. I'll be posting detailed nerdling updates in my design blog.

 

[cruisedeisel]

I imagine the results will be awesome. Im just old school. For newer production vehicles, companies hire engineers to engineer things to brake at x amount of hours. I can guaranty you that nobody will be collecting newer fords or north american cruisers in 30 years.

Other than that. I too warm up my engine and spray water in the turbine before my oil changes. So far so good. My friend is an engineer for BC Ferries and they do a similar water steam before every oil change. Im sticking to it.

 

[RufusTheDufus]

I have a DYNO-mite engine dynamometer for development. It should make it much easier for me to know what works and what doesn't work instead of just the seat-of-the-pants meter. (I can't find a place to calibrate that meter for me.) I also have a spare 3B that will be a dedicated development engine too.

 

[Dougal]

What will you use to control the vanes? I only know of one standalone VNT controller...

I've got plans for a simply pneumatic controller. But I have yet to build and test it.

 

[cruisedeisel]

I imagine the results will be awesome. Im just old school. For newer production vehicles, companies hire engineers to engineer things to brake at x amount of hours. I can guaranty you that nobody will be collecting newer fords or north american cruisers in 30 years.

Other than that. I too warm up my engine and spray water in the turbine before my oil changes. So far so good. My friend is an engineer for BC Ferries and they do a similar water steam before every oil change. Im sticking to it.

Planned obsolescence was the term I was looking for.

 

[gerg]

aspirating steam as opposed to a spraying a droplet would be much better on a compressor. I think there are some great merrets to steam cleaning and water injection in moderate amounts, but if you do misted water it would be wise to do it post turbo as the compressor is too weak a metal to handle the impact.

I too agree that there is no future for most if not all of the vehicles we see driving around.

 

[JCRover]

Dougal,
Interested in how altitude would affect your evaluation of the turbos here.

I live at altitude (~5200 ft), and often travel over ~12k ft passes often. I've got the 4BD1t in a Perentie 6x6 with the factory 4.7 gears but on ~35" tires, so I'm running up at max RPMs often on the highway yet still need good bottom end torque (I wheel and tow with the truck). I've tried the HX30W but it spools late, and I'm still looking for even more top end power (still have yet to inter-cool though). Heck, I've been struggling with high EGTs too, flat highway roads are running at ~1000-1200, and 1300-1400 on grades (where I have to keep backing out of the throttle to keep it down, hence loosing speed and power). I'm planning to regear to 4.10s, but need more power if I do so. - Really would prefer a 5 or 6spd tranny, but not an easy option with the 6x6
I've been following some of your threads, but have a long way to go to really understand compressor maps in choosing turbos. I had thought a variable vane would have been the way to go but your comparison between the two here has me really wondering.

Thanks, JC

Choking means the turbine can't pass more gas without either a decrease in temperature (EGT)or an increase in pressure.

Wastegated turbos run in choke and use the wastegate to increase/decrease drive pressure to regulate the power the turbine produces and thus regulate boost.

But on a VNT you've got no wastegate, so if your airflow requirements surpass the flow capacity for the turbine you're in for a lot of pain. The turbine starts to need a lot more pressure to pass more exhaust and this makes drive pressure spike and kills engine power but still delivers boost. Giving you the false impression that it because it's still making enough boost it should be working well.

It's a similar situation to clamping the wastegate on a turbo that needs the wastegate. You hit the wall power wise but still have plenty of boost. EGT can be okay but if you give it more fuel, it chokes even worse, hitting the wall at lower rpm.

On a 3B you'll probably be okay with a GT2256V. But for the 4BD1T I've run a couple of scenarios between a GT2256V and a GT2259 turbo with the same turbine but wastegated. The GT2259 was only a few psi behind at very low rpm and killed the V everywhere else. I've cut and pasted it here:

1. GT2256V VNT used on the merc ML270 (I have one of these turbos).
This turbo has a 0.64 A/R turbine housing and I've assumed the VNT can pull that down to about half the A/R.


2. GT2259 wastegated (used on Hino and Iveco diesels).
This turbo has a 0.56 A/R turbine housing and the compressor can flow about 10% more.

The results are interesting.
Low End.
Essentially the GT2259 turbo still spools just as quick. Both these turbos can provide enough boost to burn 140cc of fuel and produce over 600Nm of torque by 1400rpm.
And the wastegated turbo does with with less drive pressure.

Call it even.

Mid-range.
They are pretty much equal at 2000rpm, the wastegated turbo is running less drive pressure (because the turbine is more efficient without the extra vanes).
They can both provide more boost than needed through the mid-range, for the wastegated turbo that is no problem. You simply use the wastegate to cap boost and this lets the turbine breathe a bit easier.
But the VNT turbo still has to push that exhaust through the same turbine. The only way to get less power from the turbine is lower exhaust temp. The only way to do this is to run extra boost which costs power and spikes the exhaust drive pressure.

By 2,500rpm the VNT is running 5psi more drive pressure than the wastegated turbo.

Winner, the wastegated turbo.

Top End.
The VNT has a smaller compressor, it can only do about 27lb/min which starts to cap power at the 2,700rpm point. Now we've already had to drop off max fuel with this turbo as the turbine starts to spike and not be able to flow all the exhaust at max EGT.
So from here we're continually droppping fuel and boost to stay within the limits of the turbine and compressor.
In fact, we passed peak power (~150kw) at about 2,500rpm and have been losing ever since.
Drive pressures also keep spiking and are over 30psi by 3000rpm. Basically the party is over and it's time to change gear.

The wastegated turbo keeps producing more boost and power to beat the engines dropping VE. The larger compressor doesn't start to cap power until around 3,200rpm. At which point 140cc of diesel will be delivering around 180kw.
Drive pressures are comparable to the VNT, but the boost and power are well head.

Winner. Wastegated GT2259.

Summary GT2256V
Torque over 600Nm from 1400-2400rpm
Max power approx 150kw at 2,500rpm. 27psi here.
Limited by compressor and turbine flow limits.

Summary GT2259
Torque over 600Nm from 1400-2600rpm.
Max power approx 180kw at 3,200rpm. 26psi here.
Limited by compressor flow.

So this size VNT turbo has no real advantage on our engines unless you are already limited to lower power through other driveline concerns. We need bigger VNT's for these engines, a GT2359V might do it, but I have no info on those.

Clearly Hino, Iveco and the others running GT2259's on 4-5 litre diesels have already done this work. It's always good to agree with the big boys.

 

[KenIchiNo3]

I was so excited to read about someone trying a VNT on a 3B, only to find out the end of this thread without the hands on conclusions from @RufusTheDufus
It’s been a while, did anything else happen ?

 

[RufusTheDufus]

I did some work on it but gave up on the idea of a commercial product because there are a bunch of patents out there from different companies related to methods of controlling VNT/VVT turbos. There is (was) a company in the UK that makes an aftermarket VNT turbo controller. I forget their name. edited to add: the product is the Digibooster from tuning-diesels.com

 

[KenIchiNo3]

I did some work on it but gave up on the idea of a commercial product because there are a bunch of patents out there from different companies related to methods of controlling VNT/VVT turbos. There is (was) a company in the UK that makes an aftermarket VNT turbo controller. I forget their name. edited to add: the product is the Digibooster from tuning-diesels.com

Oh, ok.
living in Europe I am more familiar with the Garret turbos used on german cars, BMW used the Gt2256v on their 3.0 engine and audi uses the gt2052v on their 2.5 engine and these two are rarely failing and they are vacuum operated as opposed to the newer electronically controlled turbos, that is the reason why I was so interested because one can find these units used here for less than 200usd
I am only reading about it. My 3.4 BJ73 is still waiting for work to get started on it and I am gathering data.
Thank you again for an interesting read. maybe the way to go is the well beaten path of wastegated turbos

 

[Moridinbg]

The European 1HD-FTE uses Garret GT2359V with VNT from the factory. Vacuum operated. From what I found out so far, it is referred to as GTA2359LV in Land Cruiser context. It happily boosts the 4.2L FTE
Very, very little information out there, but factory it should be hitting similar numbers to the non-VNT CT26 turbos found in General countries (Australia, Africa, Middle East, Asia, South America, etc) - 12-13psi.
After mods (compressor wheel & CHRA) it is good for 20-22psi.
Same housing is used in some Mercedes (OM613, OM648 engines) and BMW (M57 engine) but with a completely different compressor wheel and different VNT nozzle paddles - the FTE ones are 9.5mm, the BMW/Mercedes would be ~~7-8mm (from memory).

 

[KenIchiNo3]

The European 1HD-FTE uses Garret GT2359V with VNT from the factory. Vacuum operated. From what I found out so far, it is referred to as GTA2359LV in Land Cruiser context. It happily boosts the 4.2L FTE
Very, very little information out there, but factory it should be hitting similar numbers to the non-VNT CT26 turbos found in General countries (Australia, Africa, Middle East, Asia, South America, etc) - 12-13psi.
After mods (compressor wheel & CHRA) it is good for 20-22psi.
Same housing is used in some Mercedes (OM613, OM648 engines) and BMW (M57 engine) but with a completely different compressor wheel and different VNT nozzle paddles - the FTE ones are 9.5mm, the BMW/Mercedes would be ~~7-8mm (from memory).

How about the turbo from the 3.0 D4d ?
i recall it’s also a VNT turbo (also watercooled which might just add some problems). I rememeber getting a quote from a turbo shop, around 280 Euro to rebuild the core. Also vacuum operated and reliable from what I’ve heard.
anyone tried that ?