GT1749V (VNT) turbo - and comparison to your favourite GT1752 added.
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Slightly O/T as it's from my TDCi Mondeo.

But if anyone is interested, this is how they work (and fail) :)

Personally I would prefer to call them IGV (variable Inlet Guide Vanes) as that is what I'm used to calling this design at work for much larger machines, but the principle is the same.

The turnine inlet has variable nozzles to alter the flow angle, so control effeciency/performance at different flows.

Crap first picture from tonight



You can only (just) see tha actuator arms in this photo, I'll pull it apart properly tommorow so you can see the full guide vane setup.

I was surprised at how many guide vanes there are, I was expecting a lot less on such a small turbine.

In this case the shaft has clearly failed :)

The guide vanes seem to be siezed so I expect the shaft failure was due to overspeed.

Edited by Rod S on 16th Sep, 2011.

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

That is from a pug engine ford isnt it? I had fun stripping one of thoes quite a few years ago never really understood it though

Drives
-Ford S-max Mk2 Ecoboost
-Rover 100 VVC #2 - track project

Searching is all you need on TurboMinis

Not quite sure how I posted the same thread twice..........

Actually from Fords own engine - about a year before they finally accepted they couldn't build a decent diesel so went into the joint venture with Peugeot/Citroen.

No doubt ancilliary parts like this will be shared. Even the Ford engine had three different turbos over about a two year period - conventional wastgate first, then VNT with an air actuator (this one) and then VNT with an electronic actuator which I think was retained on the pug version.

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

Is.that one the.gt15 vnt? Looks very similar if its not

Drives
-Ford S-max Mk2 Ecoboost
-Rover 100 VVC #2 - track project

Searching is all you need on TurboMinis

Possibly but it's not a complete turbo as we know them.

Ford decided to have the whole exhaust manifold and turbine casing cast as one huge lump rather than bolt a turbo onto a manifold.

The rest is Garrett but I'm struggling to make sense of the part number.

Not sure if Garrett did the big exhaust manifold casting as well or whether they just supplied the core/compressor for Ford to bolt in.

Edit - the whole manifold assembly is Garrett too - I've just found their name cast into it........

Edited by Rod S on 27th Aug, 2011.

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

The compressor housing ont the gt15vnt on the pug 1.6d engine and some of the 2.0 was etched on, massivly hard to find if its dirty.
The gt15 vnt would be good on a 998 not sure about 1275 though, thouh when i was driving at sainsburys the merc sprinters had a very odd hybrid style vnt turbo, quite small exhaust houseing amd massive compressor housing, they boosted from very low in the revs and kept a constant pull untill the gear change.

Drives
-Ford S-max Mk2 Ecoboost
-Rover 100 VVC #2 - track project

Searching is all you need on TurboMinis

UPDATE - First it's a GT1749V turbo (I have posted another thread about these yesterday) and they are genuine Garrett but the core fits into custom exhaust manifolds whether it be Ford, Renault, VW etc. so they are all slightly different.

The actual failure that led to the broken shaft,



Part of a turbine blade missing (and associated damage to adjacent blades)



Severe rub marks on the opposite side as soon as the assembly became out of balance. At the speed they run the S/N curve would have meant failure of the shaft was inevitable.

So I'm not sure if the siezed guide vanes caused an overspeed and the blade failure or if the blade failed and a bit of debris got into the guide vanes....

Anyway, bought a salvage turbo - had a bit too much play in the bearing cartridge for my likeing so that's in bits for a new bearing/seal kit - and bought a replacement turbine wheel/shaft and compressor wheel for this one once I sort out the guide vanes.

Obviously "chinese" copies but interesting to see the balancing.


Outside of wheels, fairly similar.



Inside a slightly different story on the compressor wheel. A lot more balance required, BUT, it has two, maybe three passes of the machine. So maybe not all "chinese" stuff is crap ???

I'll get the IGV ring (variable nozzle bit)
out of the exhaust housing of No1 later.

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

very interesting post Rod thanks

1972 998 TURBO SLEEPER

Bear with me while I add the GT1752 photos....

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

So I took the scrap GT1752 apart today to compare it to the GT1749V from the Mondeo (and lots of other makes) turbo diesels.

So far as I can understand the Garrett numbering system the GT17** is the frame/core size (whether water cooled or not) and the outside diameter of the turbine wheel.

the other dimensions (inside diameter of turbine wheel, inside and outside diameter of compressor wheel) then alter the A/Rs of the turbine/compressor whilst still keeping the GT17** title.

Please will anyone correct me if I'm wrong on that assumption.....

The V at the end just means it is a VNT turbine instead of a wastegate turbine.

So for the pictures,




The core really didn't want to come out, when I finally got it free a small part of the core casting broke off - from the oil contamination it looks like it was already broke.

From the amount of carbon you can see the bearing sleeve is totally fucked





Shaft is really scored too suggesting serious oil contamination.



Amount of balancing on a standard Garrett wheel

And comparisons between the Saab (petrol) compressor wheel and (new) TDCi wheel



and compressor housings.



There is a lot more to a GT17** than the number, it's a shame all the maps for all the variants aren't available.

...... unless any of you know better ???

Edited by Rod S on 16th Sep, 2011.

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

yep it is a shame there's no maps,

if both the compressor wheels are 17's you might find its easy to machine the housing to fit, from what I have seen on GT25's the curvature stays the same so if you cave a copressor with a bigger inducer you can jsut machine the hole out,

this is what I did on the turbine side of my GT2559v as I couldnt get the right turbine wheel, so the turbine exducer has gone from 41mm to 45mm, interestingly the Inducer is bigger but as long as the tip height is the same the wheel goes in.

Also on a lot of VNT's they cutback the trbine wheel from the factory to increase the flow.

I took the rest of the inlet guide vane assembly (the VNT bit) apart the other day, basically just to see how complicated they are (The Mondeo has the second unit going back on it so I didn't need this one).

A better picture of the actuating ring. Basically the lever arm fits in the cutout at the top of the picture and rotates this ring clockwise/antoclockwise a few mm thus swinging the actuation arms.


The actuator ring runs on three rollers but they just lift out (they are trapped in place by the turbo core section once it is fully built).

Then three torx headed screw hold the sub-assembly in place. I thought I would have to drill them out (because of the heat all this has been exposed to and T20 heads round off very easily) but they came out with an impact driver un-damaged - they are out in the picture above.


Then the sub-assembly just lifts out, this is it turned upside down showing the guide vanes (or "Variable Nozzles").

Stainless backplate with the spacers that hold the sub-assembly at the right distance.

Looks like it's pressed in, I haven't tried to get it out yet. I suspect it's initially held in by the three torx screws sandwiching the lot to the cast iron but has since corroded into place.


If I can get it out, I want to measure it up to see if a T3 housing could be machined to accept it all :)

Edited by Rod S on 21st Sep, 2011.

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

I thought the 3 holes were jsut machined straight into the exhaust housing on the ones Ive had apart, maybe not.

how about winding in a long torx screw(s) till they bottom out, it may jack it off the exh housing.

Is this data of any use for the compressors?

http://www.turbomaster.info/eng/applications/compressor.php

Good idea Joe, I'll try that tommorow (in daylight).

If it is, there must be an other anti-rotation pin in there somewhere as the only one I've seen so far is between the cast iron parts to align the guide vane drive mechanism.

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

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

the od of the turbine ,,denotes the 'family' rod ,eg gt17 44mm od ...then you have variations in id and a/r and maybe tip height ..(i think).

Edited by robert on 22nd Sep, 2011.

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

Ive seen variations for the OD of the turbine in the same family, so its anyones guess really.

I think you may find the tip heights on VNT turbines are higher than conventional turbo's too, *presumably* because a) they need more room for the vanes, and b) they need more flow so the VNT can actually limit boost.

Edited by Joe C on 22nd Sep, 2011.

Looking at any of the Garrett VNT turbos on Turbomaster, says that they are no servicable. It must be that your average turbo shop cant work with so many little parts on one turbo. lol

really joe thats interesting ,what the data ?

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

It's an interesting subject for sure. Garrett's own documentation says that, for the GT series the first two numbers are the frame size and turbine wheel fixed OD, but then go on to say that rule doesn't apply to GT25 or 28.....

I have certainly seen different turbine wheel diameters on the T series so if there is any commonality it appears to apply mainly to GT series.

But the company who supplied me with a new wheel/shaft for the Mondeo was adamant that, although they all use GT1749V, the Ford wheel is different to the Peugeout/Citroen version and the VW/Audi one is different again (only the OD is the same).....

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

I meant to put pesumably in that post,

when I was looking at turbines I kept seeing smaller to height ones than mine, cans teem to find them now,

on my vnt Ive transplanted in a non clipped 54 x 45 x 7.8 mm turbine to replace the 52 x 41.5 x 8 mm clipped vnt wheel

on my vnt wheel it was clipped by about 3mm. also the VNT wheel was 9 blade, the new one is 11.

this has some turbine dimensions,

http://www.turbointernational.com/products...23&turbotype=35

an ebay is worth a look too.

Edited by Joe C on 22nd Sep, 2011.

I hadnt even looked at the 17 parts!

I think there is a typo in their dimentions though, I cant see the exducer being larger than the inducer on the turbine.

They show the 70 trim as the 001 and the LPT as the 003. I have a 004 and Turbomaster suggest that has the LPT turbine, and that all of those are superceded by the 005 with the LPT turbine.

I'll get the calipers out again