VW TDI forum, Audi, Porsche, and Chevy Cruze Diesel forum banner

1 - 8 of 8 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter #1
Good day,

I've looked around the site looking for advice on basic care to stop the VNT Turbo vanes clogging up & basically what I need to do to "Exercise" the Vanes while driving.

I always on long up hills or motorway on ramps/slip roads try & accelerate hard in each gear from 1900rpm to 3500rpm but I don't know if this is the ultimate.

I don't know how to get the vanes to move through their total range........

If I accelerate up the hill in a High gear I assume that because of low exhaust gas velocity the vanes will be angled to give higher velocity over the turbo, if I accelerate hard in a low gear and therefore high exhaust gas velocity (& temperature ?) the vanes will be such that they will be at the other end of the range ?

Where to the vanes sit when the engine is off (ie no vacuum) is this at the angle for low exhaust gas velocity/high boost or for high exhaust gas velocity ?

Thanks Paul
 

·
Premium Member
Joined
·
23,902 Posts
The vanes really move at a relatively low rpm, around 2000 or so. I forget the exact value but you can see it in the VCDS tool measuring blocks.

Really, the reason for accelerating hard for at least a few seconds on a warm engine is that it heats up the turbo and engine which helps to burn off and blow out any buildup.

Take a look at the VNT actuator adjustment article in the mk4 FAQ, it shows how the vanes move and explains more about how they work.

Also, this is a bit more technical than a quick intro so post moved to mk4 section.
 

·
Premium Member
Joined
·
5,942 Posts
Hi Asseri, just give it a good clean, I can't see why any turbo would need replacing unless 1) the seals are gone and it's chewing oil 2) the vanes have disintigrated but I've never heard of that yet 3) It's one of those daft ones that you can't get an actuator for and needs to be replaced as a complete unit.
I hate this modern way of replacing things rather than being able to pull them apart and replace a part.

Anyway welcometomyturbodies to you both:)
 

·
Registered
Joined
·
4 Posts
Discussion Starter #6
Thank you guys for the advice & welcome.
I understand how the VNT turbo works I just wondered if I could work out what puts the Vane angle at one end of its full travel to the complete opposite at the other end of their travel. (To ensure no "sticky bits").
Would I be right in saying if I did 2000-2500 RPM in a High Gear up a hill that this would create max boost for a low velocity Exhaust gas so this would be one end of the travel of the vanes. Then 3500-4500RPM up a hill but say in 3rd would be the other end of the vanes travel (Boost coming from high velocity exhaust gases which would also blow/burn off any carbon ?) and to "Exercise" them would be to alternate between this two options ?

Paul
 

·
Premium Member
Joined
·
9,654 Posts
Welcome to the forum. welcometomyturbodies

Diesel Variable Geometry Turbo Introduction

A slower VNT operation

As this thread says Basic Turbo Care. The basic care for a turbo is oil changes at the specified times. When you stop the engine don't rev it up before you turn it off (as the boy racers do). The turbo can spin up to 160,000 rpm when working so you turn the engine off but the turbo can still be spinning with no forced lubrication.
 

·
Premium Member
Joined
·
23,902 Posts
The problem is not that the vanes will not otherwise move enough on their own. The problem is that buildup makes them stick in place and limits their movement. RPM is only part of the story, the high heat to cook and blow out any buildup is more important. Don't think low velocity gas by low rpm-high load. It's not as good for the engine as medium rpm-high load either.
 
1 - 8 of 8 Posts
Top