VNT turbochargers explained

[@ArtOfDiesel]

I really like this video! You are so right in so many ways. Not to be a PITA on one detail, and perhaps somebody else already said this, but the reason that the turbine spools up fast with the vanes in the nearly-closed position is because the exhaust gas flow has been accelerated by the narrow openings and angled in a fashion that it moves in a more circumferential motion that helps the turbine spin up. You are right that there's higher pressure under those conditions, but that's seen upstream of the variable vanes as a side-effect of closing them down. That higher pressure wouldn't be seen by the turbine itself. Naturally, as the vanes open, not only is there less acceleration of the flow, but the flow is also in a more radial direction, both of which contribute to less spooling. That's my understanding of it, anyways. Thanks for the excellent video!

[@PiggyPower]

Yes, spot on .. it does see the high pressure though, think of 2bar of air forced through those narrow vane's!

[@ArtOfDiesel]

@@PiggyPower it really is pretty incredible what this machinery goes through. the VNT really is an amazing innovation. I used to have a MK4 Jetta TDI and that thing got 45 mpg no matter how hard I drove it. Hoping I can sort out my E320 CDI for good performance and great efficiency, too.

[@PiggyPower]

Those things are possible.... A reliable E320 .... Errrm

[@23wjam]

I could get used to more videos like this.

[@PiggyPower]

I'll keep that in mind.... However my depth of knowledge kind of wanes after VNT turbochargers 😂 Thanks for watching and commenting 😁🐷💪

[@winstoncorey2023]

Instablaster...

[@Yogaslackers]

Do you have a video on how to retrofit these on a waste gated vehicle? How can the vnt be controlled with no computer?

[@PiggyPower]

It can be controlled via boost can or an Arduino system

[@Yogaslackers]

Thanks for the quick response, we are building a bit if a Frankenstein diesel engine, a 16v 4d56u block with an 8v 4d56t head. I'm trying to keep everything simple with no ecu. Everything is mechanical. We just bought a VNT, with vacuum controller, still a bit confused. We are running a kzbin.info/www/bejne/hGW1fodpnL51rMUsi=582p6ha266G5ieai an this be adapted?

[@Yogaslackers]

This is the Turbo kzbin.info/www/bejne/f6SyoWdvo9CHmNUsi=hqrmb7SoFc2XOeSy

[@PiggyPower]

Ive never seen or used that controller sorry. If you want to keep things simple ....don't use a VNT. Find a modern wastegate turbo.

[@Yogaslackers]

​@@PiggyPower maybe simple was the wrong term, I was hoping for a balance between the computer world and analog world. I think the VNT will be a good fit for our needs, I was just looking for more information on how to control it. Really appreciate your style and breakdown of how a vnt works it was very helpful.

[@billybeetle]

Thank you piggypower for clearing that up for me 👍🏻

[@PiggyPower]

You are most welcome 👍🐷

[@chamoisshine9951]

Hi Piggy, thanks for your help over xmas on my timing belt change. Ive been chasing through a p0243/p0238 prob (eml at 2700 under load) 1.6hdi110 and i think it's the vnt turbo. I took the vacume actuatee off and the nozzle control arm is stiff and gritty and only moves about 10mm (unless i really force it) is it better to rebuild or to replace? Thanks in advance. Kev

[@PiggyPower]

You can clean them out. Mr Muscle oven cleaner works a treat. It should be freely moving with no resistance at all

[@chamoisshine9951]

Thanks have you got a vid, or know of one you recommend

[@PiggyPower]

@@chamoisshine9951 no sorry

[@chamoisshine9951]

Well not a complete disaster. Just a disaster LOL. Took turbo off (3 hours of fun) and indeed the arm was stiff. Split turbo in half and the control ring wasn't moving freely. So cleaned and replaced and it seemed to be a lot better but some of the flaps were still I little gritty. So decided to take out the nozzle ring. Unfortunately the 3 screws that hold it in place have seized and I have snapped them all!! Ordered a new turbo (remanufactured Garrett original) should arrive tomorrow. Old turbo is now clean and all parts moving freely, just can't re-assemble. Next time (if there is a next time) I'll just clean the ring and just use lots of cleaner until the vent flaps are less gritty). A remanufactured original was only £50 more than a new Chinese copy. I'll let you know how I got on.

[@PiggyPower]

Yeah they tend to snap after all that time. Pop it on a drill press. Drill them out. Retap. Fit new tiny bolts. I've done it a few times! Kudos for trying though pal, many would write the car off!

[@bouncingover]

So if i have overboost problem i need to extend the westgate arm,or underboost problem,i need to shorten the westgate arm right?

[@PiggyPower]

For a VNT? Depends how the veins/arm is setup to be honest. Also depends if you are overshooting on boost or constant overboosting/underboosting ...

[@bouncingover]

@@PiggyPower yes,golf mk4 tdi,90hp....garrett turbocharger

[@PiggyPower]

If you have an issue with overboosting on a stock turbocharger/power, then something else is wrong.

[@blairarcher8952]

I have a VNT on my Saab.Its a little sluggish at pull away .Great when it gets to fly.What do you think of Mr Muscle down the Egr outlet to clean the arms?

[@PiggyPower]

Check if they are seized or not first 👍

[@blairarcher8952]

Great channel thx

[@PiggyPower]

No worries. Don't always assume the worst. Always check 👍

[@bobt8985]

I have a vnt on my 02 golf with 482,000 miles. I think the vanes are sticking causing limp mode. The bolts are so rusty, I am afraid they will brake. Can I drill into the exhaust and shoot a foaming cleaner into it? Then plug the hole?

[@PiggyPower]

At that miles, probably just worn tbh! I wouldn't want to suggest anything like that due to the potential risks.... Not that I wouldn't try it myself 😆

[@stu962]

Great video, have you found a good way to match the full boost vane position ie at end stop when changing to a new CHRA. Not easy to measure and I dont have a flow bench

[@PiggyPower]

On the road... Fiddle...drive...fiddle...drive... Lol

[@manuqtix8874]

Ok I have some questions. -Can the exhaust gas pressure force the vanes open as in a normal wastegate? -what’s the pro and cons of using a boost reference wastegate and a vacuum reference wastegate on a Variable vane turbo?

[@PiggyPower]

1) not really, if they 'open' then EMPs drop, which would allow them to shut ..etc.. ...but then the flow would be increasing as RPM goes up anyway... If EMPs are high enough to move the vanes, there's other issues. 2) not really sure what you mean by having a boost reference v a vacuum reference. There's no vacuum on a turbo diesel. Just the pump.

[@allyouneedis4x4]

Still I can't understand the difference in control between VNT turbo and old type of turbo with wastegate.. Example we set maximum pressure 15psi, so if the pressure raise, ''old turbo'' will open the wastegate to decrease pressure on hot side. And on VNT the same, just not wastegate, but change angle of the flaps. Can't understand the difference in control? Why it is so tricky and difficult to put VNT?

[@PiggyPower]

In plane and simple talk, yes it's like that, but these VNTs are so much advanced that a tiny movement on the vanes creates a huge difference. Plus you don't want high EMPs while cruising, but you do want quick response. You also don't want overboosting which is VERY easy with such a simple setup. These will easily spike to crazy psi if not under control and destroy themselves. Plus if the vanes are shut too much for too long it will choke the engine and prevent it from breathing Plus the advantages... Essentially you have a turbo that is too big for the engine to spool, but with the vanes, it can spool it. Then you have the bonus of it flowing air much more efficiently being a bigger blower.

[@breezify9985]

Great video! Out of curiosity do you reckon much can be done with the 1.4 hdi variant of the 206 engine? Other than a remap, would this even be worth doing? Thanks!

[@PiggyPower]

Not much point if I am honest .. have you seen the size of the turbo on them?... Better off saving for the bigger engine variants and enjoy the savings of the mpg benefits of the 1.4

[@PiggyPower]

Thankyou for the comment and watching 👍 🐷💪

[@breezify9985]

Piggy Power No problem, just had a look and the turbo is tiny lol. Just wondered anyway. Only trouble with the bigger engines is the insurance due to my age. Thanks again!

[@PiggyPower]

I would think a bigger engined version insurance is cheaper than a modified small engine car?

[@breezify9985]

@@PiggyPower Good point, i'll definitely look into it. Thanks.

[@Bobby_The_Retrofit_Nerd]

This was a very informed video well done keep up the good work

[@PiggyPower]

No worries! I try! Please smash the subscribe button...if you like 👍🤣🐷💪

[@Chriswales]

Good guide to VNT turbos, clearly the other guy didn't have much knowledge. Maybe he should've just admitted that and not said anything about them. I owned a 306 Dturbo and it was good at the time, I replaced it with a Leon with the VW TDI 110 engine. The drive ability of the cars was completely different, the VNT turbo on the Leon makes it much better. I'd never want to have another waste gate turbo on a diesel. You could hustle the 306 along, but you had drive around the turbo lag low down and it was game over then waste gate opened. Giving you a power band of a little over 2,500 revs. The power delivery from the VNT turbo on the other hand has very little lag low down and no sudden drop at the high end.

[@PiggyPower]

Many thanks. And well said... VNTs transform the older diesels

[@Spellspt]

Any links/tips to control a VNT without ECU. On an older XUD9. Ive heard about using a boost can, but never seen one or how to do it.

[@PiggyPower]

Plenty done it, will do and still do. Just not very well. Arduino system would work much better, as I did with the Racetractor 👍🐷💪

[@heinzletzte.6385]

I always wondered why they couldnt make these adjust the fan blades all by themselfes with some kind of pressure system triggering some mechanical component as boost rises when they spool up.

[@PiggyPower]

Hi there, thankyou for commenting and watching... Your question; 1) In early days, they did, it's nicknamed a "boost can" and many use it to control a VNT on a project car if they have no computer system to aid control. 2) it just doesn't work very well at all, creates boost spikes and high EMPs often when cruising. 3) essentially a modern ECU controlled system is actually doing what you describe... The "pressure system" is the exhaust manifold and inlet manifold... The mechanical component is the vacuum or motor control alongside those mechanical vanes... It's just progress 👍 Your question was good though and was a side subject I was going to cover in this video but felt the video would end up too long Thanks for watching and commenting, I hope you enjoyed the video and like the Piggypower channel 🐷💪

[@harrylee833]

Would a GTB2056VL from a 2.4 D5 Volvo be ideal for an upgrade on a DWATED 8V 110?

[@PiggyPower]

Depends what you mean by "ideal" and "upgrade" ...

[@harrylee833]

@@PiggyPower as in, custom stage 2/3 map, ideally 160+ bhp and nearer 300lb ft torque

[@PiggyPower]

It would fit that brief remit. You need to understand that you will need a good mapper and understanding of making it work. Custom fabrication and a fuel system and engine that can support it. But ... Please try it and let me know 😂🐷💪

[@lostwill86]

More vids like this!! Maybe a video on how to control them on an xud

[@PiggyPower]

Thankyou. I did a lot about that subject back on the racetractor if you're that interested!! I can try and do something specific though

[@radionautomatic]

I thought the exact same thing about that skid factory video. Love what they do but vnt isn't really a big thing on diesels in oz. It's more relevant here as we've got heaps of fairly small engined diesels

[@PiggyPower]

Perhaps that is the issue... Although I was still surprised at his 'facts' being so wrong.

[@radionautomatic]

Yeah same. Gfb now do a manual vnt controller. I think they need to revisit that td42 build and put a proper vnt turbo on it to feel the difference

[@PiggyPower]

Manual VNT controller... Just a boost controller. Very inadequate and poor control of a VNT. Agree on the td42 thing. Be epic that with a vnt

[@radionautomatic]

@@PiggyPower it won't be optimal, but gfb are a pretty reputable company. Looks like a more complex 2 stage valve, take a look. I run a gtb1756vk on my mg zr diesel, it uses a custom electronic mappable pwm controller. Took some setting up but that's the way to do it.

[@PiggyPower]

I used arduino on the Racetractor which is now gone. Currently just use the edc15 Bosch ECU that has boost control capabilities built into it. I have seen many manual 2 stage or even 'tuning box' style VNT controllers... None yet have I seen do any better of a job than a well setup boost controller... Which is £15. What you have setup sounds great. Are you in Aussie land? Would love to see your setup! I have always intended to do a tutorial on VNT control using a Arduino setup but the Racetractor getting written off scuppered that

[@J.F.K.O]

yeah you are right Yoda got a couple of things wrong, i wonder if he just by mistake moved them wrong when he explained that they make more boost when open. But he sure don't seem to like vnt's :P

[@PiggyPower]

You wouldn't like them if you didn't understand them... That's true of so so many things... "I hate that" ...do you understand it, "no"... They often correlate. They don't make more or less boost when open or shut... They just adjust the pressure/EMP... Rpm, load and fuel all play a part . Which is why they need such fine tuning to control

[@maxautouk]

Trust you much more than turbo Yoda, he's great though

[@PiggyPower]

I don't trust my welding more than turbo Yoda! 😲