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Joe C

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Carlos Fandango

Burnham-on-Crouch, Essex

the tollerances are pretty big,

on the desils apparently they can soot up and eventually jam,
on petrols its speculated that the materials used can melt, i suspect this comes from some form of production testing....



In our world as Ive said I dont think there is too much to worry about, when on boost we'll be running rich, and thats woried about it should be running some form of overboost protection.


Edited by Joe C on 20th Oct, 2011.

On 28th Aug, 2011 Kean said:
At the risk of being sigged...

Joe, do you have a photo of your tool?



http://www.turbominis.co.uk/forums/index.p...9064&lastpost=1

https://joe1977.imgbb.com/



Rod S

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On the two diesel (1749VNT) I've just had apart, soot wasn't really an issue.

The one from my own car was sticking because a couple of the guide vanes were ever so slightly bent after part of the turbine wheel came off and hit them. No soot at all, but it never did give off black smoke like some TDCis do.

The secondhand one I got from eBay was well sooted up but vanes moved fine (that one is in my Mondeo now after a rebuild and works fine, shame about the rest of Ford's engine design... (DMF failure so my starter motor is now f**cked)).

The materials of the vanes seems a high grade stainless, possibly even nimonic, as there is no sign of discolourisation etc.

I think VNT is the way forwards for us, keep up the good work Joe.

Schrödinger's cat - so which one am I ???


Paul S

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Formerly Axel

Podland

I'm reasonably satisfied that a VNT on a rarely used Mini turbo is going to be OK. Now that VNTs are common place and doing 100,000 plus miles on a production diesel, they have to be rugged enough to cope with extreme conditions, including short term high temperatures.

What I'm still not clear about is if they are used without a wastegate, do they impose a high TIP? Or do they just open up and generate the shaft power from more flow and less pressure?

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."


miniminor63

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The oversills police

Oslo, Norway

Isnt Porsche using VNT on petrol engines


Yo-Han

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North of the Netherlands

We had a tolarance issue at work yesterday, read this thread and thought I should make a remark. Would be a shame if you found out the hard way... *smiley*
Nice picture Joe!

Dazed and Confused....


robert

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uranus

damn , i just remembered i have a vnt 2259 ...temptation..

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM


robert

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uranus

http://www.youtube.com/watch?v=iwAFznIW_Zg

http://www.vwdiesel.net/forum/index.php?topic=19438.0

hmmm mechanical control ..
http://mercedesforum.com/forum/diesel-perf...ine-load-49672/


electronical control ...

http://dmn.kuulalaakeri.org/vnt-lda/

Edited by robert on 20th Oct, 2011.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM


Paul S

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Interesting bit about shock waves from my text book:



So this got me thinking, to prevent the shock wave, shorten the manifold i.e. hang the turbo on the back of the engine, old style, and see what happens.

Hey presto, shock waves gone from the inner cylinders and lessened in the outers, but also lost 5hp at peak :(

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."


Jimster
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455bhp per ton
12 sec 1/4 mile road legal mini

Sunny Bridgend, South Wales




On 20th Oct, 2011 miniminor63 said:
Isnt Porsche using VNT on petrol engines


thats what I was thinking

Team www.sheepspeed.com Racing

On 15th May, 2009 TurboDave said:

I think the welsh one has it right!


1st to provide running proof
of turbo twinkie in a car and first to
run a 1/4 in one!!

Is your data backed up?? directbackup.net one extra month free for all Turbo minis members, PM me for detials


Paul S

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Porsche do indeed;

http://www.aerocharger.com/kits_porsche_930.php

But I reckon that manifold will drop the EGT a fair bit.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."


miniminor63

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The oversills police

Oslo, Norway

Thats aftermarket. They use it on brand new ones from the factory.


Paul S

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Formerly Axel

Podland

Yep, just using the link to show how the manifolding is done. I assume that the factory must mount it in the same position.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."


Rod S

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Rural Suffolk

Without getting too bent out of shape, it seems the average head gasket life on this forum is 1k miles. pistons maybe 2k miles, blocks not much longer when the head gasket fails and thrust bearings fail even quicker.

So 100k on a production diesel seems good - my VNT lasted 65K and that was on a Ford.

Can anyone destroy a VNT on a Mini before the rest of the engine ???

No evidence so far :) :) :)


Schrödinger's cat - so which one am I ???


jbelanger

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Montreal, Canada

The OEM Porsche setup is like this:


It's difficult to see in this picture but it's much shorter than the aftermarket setup shown above and it's also twin turbo.

Jean

http://www.jbperf.com/


Joe C

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Carlos Fandango

Burnham-on-Crouch, Essex

bang on!

my last lump did 5-6k before its untimed demise, i defy any one to kill a VNT 's vanes before 20k on an A series.


On 21st Oct, 2011 Rod S said:
Without getting too bent out of shape, it seems the average head gasket life on this forum is 1k miles. pistons maybe 2k miles, blocks not much longer when the head gasket fails and thrust bearings fail even quicker.

So 100k on a production diesel seems good - my VNT lasted 65K and that was on a Ford.

Can anyone destroy a VNT on a Mini before the rest of the engine ???

No evidence so far :) :) :)


On 28th Aug, 2011 Kean said:
At the risk of being sigged...

Joe, do you have a photo of your tool?



http://www.turbominis.co.uk/forums/index.p...9064&lastpost=1

https://joe1977.imgbb.com/



stevieturbo

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Northern Ireland




On 18th Oct, 2011 Advantage said:
It is said in the automotive business (where I work) that VNT for gasoline engine are not a valid option as of today.

On a gasoline engine, the vanes and added mechanic has to cope with much higher temperatures than with a diesel engine.

I have in mind the followings :
Gasoline : 1050°C
Diesel : 700°C

Ever wondered why VW built its hi power TSI with a supercharger AND a turbo if a VNT was available and suitable ?
Twice the parts is twice the price and twice the hassle.

I would stay clear of VNT's ... except maybe if I got given the turbo for free !


Pretty sure Porsche already offer a VNT petrol setup ?

And as others have said. Warranty and durability are paramount on an OEM setup. They have to warranty vehicles for high mileage and all sorts of use or abuse.
Mini owners wishing to fit a cheap second hand turbo dont really have those same considerations.
And if their TSI setups were so good....everyone wouldnt be crying about them drinking nearly as much oil as petrol.
So they didnt get something right there !!

And whether petrol or diesel, airflow is airflow. And airflow combined with some fuel is what makes power.
So turbo fitments based on overall power/torque potential are still valid regardless of fuel

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will


Paul S

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Formerly Axel

Podland

This was intended to be a discussion about the options to reduce the boost threshold. We seem to keep going back to the suitability of VNTs on petrol engine.

I'm satisfied that the VNT is an option on the A Series. Joe has proved his to work OK and get some miles on it. Let's face it, if anyone could bust a VNT, it would be Joe :)

My main concern is still the issue of passing all the exhaust gas though the turbine and creating VE damaging back pressure.

As for the TD04L-12T, it is a bit of an oddball, even in single scroll form. Similar compressor wheel size to a GT1548 and a turbine wheel similar to a GT2052. Wheel size does not tell the whole story, but I would imagine it to be slow to spool and that's why they have upgraded it to a twin scroll.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."


Rod S

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OK, back to the point....

You're either going to have to measure the pressures or try to do some calculations but without any benchmark from any engine, calculations are going to be marginal.

One thing that does occur with respect to their dominance on diesels, there is another big difference apart from temperature..... diesels generally consume the maximum amount of air they can physically flow irrespective of required power output, and regulate power by altering the fuel flow only.

So for maximum power the limit is essentially air flow in both cases but at low power the diesel exhaust gas flow will be more than the petrol (probably why they deliver boost at lower RPMs). For that reason alone I don't think the manufacturers would tolerate a design that was particularly restrictive.

Schrödinger's cat - so which one am I ???


Paul S

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Formerly Axel

Podland

The rev range of a diesel will mean that they do not run much or even any overlap on the cam. Hence a bit more back pressure can be tolerated. A petrol engine at 7-8k is a different matter.

I expect, but need data to confirm, that the VNT nozzles work both sides of the "normal" nozzle size i.e. they open up bigger as well as close down to bring boost in early. Much like the VVT in my Fez where I see as much benefit at 2k as I do at 7k.

I wonder if Joe could get some TIP data? Where's he gone?

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."


Rod S

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On 22nd Oct, 2011 Paul S said:
The rev range of a diesel will mean that they do not run much or even any overlap on the cam. Hence a bit more back pressure can be tolerated. A petrol engine at 7-8k is a different matter.

Good point.

On 22nd Oct, 2011 Paul S said:
I expect, but need data to confirm, that the VNT nozzles work both sides of the "normal" nozzle size i.e. they open up bigger as well as close down to bring boost in early. Much like the VVT in my Fez where I see as much benefit at 2k as I do at 7k.

The other interesting thing I noticed in the Garrett catalogue is they don'y quote A/Rs on the exhaust turbine but a series of numbers, VNT, VNT1, VNT2, VNT3. Knowing what those numbers mean relative to the A/R on a normal turbine - as the wheel size is pretty much fixed by the first two digits in GT**** - is probably the key to your question. (My GTV1749VNT turbine wheel looks identical to the GT1752 turbine wheel).

On 22nd Oct, 2011 Paul S said:
I wonder if Joe could get some TIP data? Where's he gone?

Out fixing something else ??? :)

Schrödinger's cat - so which one am I ???


Joe C

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Carlos Fandango

Burnham-on-Crouch, Essex

LOL, been fixing my hangover this morning... *Sick* oooff!

Ive got a gauge (that Ive had for well over a year!) to connect up, I best get on the case and get some fittings on order.


On 22nd Oct, 2011 Rod S said:

On 28th Aug, 2011 Kean said:
At the risk of being sigged...

Joe, do you have a photo of your tool?



http://www.turbominis.co.uk/forums/index.p...9064&lastpost=1

https://joe1977.imgbb.com/



Paul S

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Formerly Axel

Podland


On 22nd Oct, 2011 Rod S said:


The other interesting thing I noticed in the Garrett catalogue is they don'y quote A/Rs on the exhaust turbine but a series of numbers, VNT, VNT1, VNT2, VNT3.


Well, if you reassembled your GT1749v nozzle and actuator ring and measured the vane width and gaps at each extreme of the movement, we could make a good guess !

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."


stevieturbo

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Northern Ireland




On 22nd Oct, 2011 Paul S said:
This was intended to be a discussion about the options to reduce the boost threshold. We seem to keep going back to the suitability of VNTs on petrol engine.

I'm satisfied that the VNT is an option on the A Series. Joe has proved his to work OK and get some miles on it. Let's face it, if anyone could bust a VNT, it would be Joe :)

My main concern is still the issue of passing all the exhaust gas though the turbine and creating VE damaging back pressure.

As for the TD04L-12T, it is a bit of an oddball, even in single scroll form. Similar compressor wheel size to a GT1548 and a turbine wheel similar to a GT2052. Wheel size does not tell the whole story, but I would imagine it to be slow to spool and that's why they have upgraded it to a twin scroll.


On that note.

How many have done EGBP testing on their existing setups, and what were the results ? either normal, twin, vnt, anything really

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will


Rod S

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Formally Retired

Rural Suffolk

On 22nd Oct, 2011 stevieturbo said:


On that note.

How many have done EGBP testing on their existing setups, and what were the results ? either normal, twin, vnt, anything really


Stevie,

At the risk of being flamed, I would say slightly less people than the number who have actually put dual widebands on a five port to look at the differences between inner and outer AFRs.

Doesn't mean it can't be done, just not many doing it yet :).

The price of the technology is coming down all the time at the moment, it's just the will to do it that is lacking.

Schrödinger's cat - so which one am I ???


wolfie

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If anyone like me has no idea about the twin scroll turbo i found a great article.
http://www.modified.com/tech/modp-0906-twi...gn/viewall.html

Crystal Sound Audio said:

Why wolfie...you should have your name as Fuckfaceshithead !


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