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Discussion Starter #1 (Edited)
This is a point of information really, thought id put up what i came across during the install of a 1.7 ZTH VGT turbo to my 1.7 DTI.
Mainly due to the fact that when i tried to look up some info on this there was very little info about it.
I am aware that very few would want to do this but i thought it would put the info out there as to what can be swapped.

Anyway the background.... ive had a 2003 Combo for 5-6 years bought at scrap money £450 as it was ex-fleet and they were disposing of it.
Ive put around 50,000 miles on it bringing it to 197,000 ish miles, i had an event to go to in Bristol (im in the north west) and on the way back it broke down.

One issue was the usual Fueling ECU solder problem, the other was a rotten thermostat transfer pipe, this pipe is a t"sser to get to and really requires you to take off the turbo and a lot of other stuff.
A month previous someone had offered me a corsa 1.7di in old-lady condition 100k immaculate body and interior but scrap because the rear end was rotten underneath..total bargain at £200 with full tank and 4 nearly new tyres.
Having the spare sat there i decided to swap the engine but in the process i was wondering if i could get some more go.

I had searched here and on other Vx forum sites but other than vague maybe's no-one was definite about what could be swapped so i went in to it to find out.....

So Parts required to put a VGT on to a DTI or a DI (no practical differences at the stripped engine level) are:

x1 VGT from a ZTH this is a TD03 family unit with vacuum actuated vane control (Vac=boost No vac=bypass)



x1 ZTH exhaust manifold - pretty self explanatory and it bolts straight on to the DTI/DI. (it will require its EGR port to be blocked i made a plate using 5mm steel)



x1 Feed and drain lines for the ZTH VGT turbo - not essential but makes it all easier



x1 stubby pre-cat for ZTH -this acts as the start of the down pipe and also meets up with the turbo support bracket so is quite essential unless you want to fab it all up.



x1 ZTH turbo support bracket GM 55350278 fairly specific bracket and can be had for 10-12 quid so is far easier to use than fab.



x2 Heat shields from an original ZTH Vehicle - i got mine from a scrap Meriva A.

Exhaust pipe wise an aftermarket front pipe without the emissions gubbins is the simplest.

And thats it! basically the manifold, turbo and anything attached to it!







Now to the process...



And please bear in mind this is just the way i did it each to their own, this is not a professional manual, all at your own risk etc etc........

Engine out - as i have an engine crane i prefer to take them out via the top as that leaves me with a rolling chassis.



so this is the original DTI unit, 197,000 miles, rattling clutch, worn gearbox, Leaking coolant etc

- Driveshafts off
- Gear linkage disconnect
- exhaust off
- coolant/fuel lines off
- main loom disconnect
- rad out
- crane onto engine
- disconnect drivers side mount completely
- disconnect inner passenger mount bracket
- lower engine to expose outer mount bracket in chassis leg, remove
- this then allows you to lift the engine
- rotate hanging engine anti clockwise 30 degrees approx and voila lift engine clear.



Engine on to the bench and here i am obviously switching to the DI unit from my donor same turbo setup but with different pipe work as no Intercooler.
But if you are merely upgrading the DTI the strip is the same basically all turbo and exhaust parts off the block.



Right what is shown is the DI block stripped but with the ZTH manifold offered up to check the spacing also the ZTH turbo feed pipe is on too.

Red circle: The Oil drain point for the turbo no mods needed other than a rotation Anti clockwise to line up with the new turbo drain - Pipe is a press fit in to the block and will rotate if a small pipe or similar is used carefully as a lever.

Green circles: these are cast holes in the block which will be un-tapped on the DTI/DI these need to be tapped out to standard m10 thread to hold the turbo support bracket they are the correct size for the m10 taps.

Blue oblongs: This is the pipe which acts as the Thermostat bypass it is very thinly zinc coated was as rotten as a pear on my original engine - Just keep an eye on it, a new one from vaux was about 35 quid +vat
This pipe also has a clearance issue with the turbo which i will touch on later.

Black circle: Oil feed for turbo DTI/DI have a spacer/adapter threaded in to the block this needs to be removed as the ZTH feed (shown in pic) threads directly in to the block.

Purple circle: Another rust item, the drain pipe for the vacuum pump rots like a...rotten thing a new one from vaux is a mere £100 plus vat for a small pipe - i managed to get a local hydraulics place to fab me a replacement for much less that should outlast the car.



This photo shows the combined turbo/manifold parts offered up for clearance.

In the main the setup is a bolt on fitment but there are a couple of area's that need a little attention:

The thermostat bypass pipe we highlighted in the previous post doesn't quite allow enough room for the larger turbo exhaust side housing. I looked at replacing this part with the appropriate ZTH part but the Gearbox end of the pipe divides in the wrong place in to the wrong shape of Y piece.
When i looked up the said part i noticed that the section of the pipe where the turbo interference issue was apparent, merely had a large dent pressed in to it - so reasoning that if its OEM it must be ok i did the same.
To get a nice uniform and gentle depression i used an old section of alloy scaff tube, and supporting the pipe in the vice gradually bent the required clearance checking often how much more it needed.
i ended up with about 15mm clearance which is plenty and the turbo is supported and should not be going anywhere in the first place.

The only other issue was the gearbox bell-housing as shown below:





This tab with a threaded hole seemed to be redundant so i just removed it as it blocked the intake piping for the turbo.
(please note the turbo was cleaned out thoroughly before it went in the for the last time)

After this its mainly air plumbing, the original Airbox to Turbo intake pipe from the DTI/DI will fit on to the ZTH setup with no modifications.



Also as an aside in this pic you can see the Downpipe/pre-cat attached and the custom vacuum pump drain pipe that was made up for this swap.

When you go about fitting the Downpipe/pre-cat it is much easier with the alternator and vac pump removed.
It is possible to fit and remove the pre-cat in place with the alternator there too but it would not be a pleasant in car job as there is very little room indeed.



This pic shows the engine back in and the relationship between the turbo output and the Intercooler pipes on the DTI, Basically nothing changes if you are doing this conversion on a DI i recommend you scavenge the Inter cooler and its pipes from a scrapper or similar.



This actually the view of the intake pipes as fitted to the old engine but as i have mentioned they went back in the exact same way.
The upper pipe is the Airbox to turbo intake and fits as normal, the lower pipe is the intercooler to Manifold intake and again fits as normal, i had brazed a pipe in to it to monitor boost.
The lowest section should show a stainless EGR pipe but that was long gone even before this swap, Again the fitting has been brazed, this time to block it off



Once the engine is in with all of its covers and shielding on you would be hard-pressed to tell the difference.





Controlling the VNT/VGT.....

The basic issue with controlling the Turbo on this conversion is that the ecu on each different vehicle controls its turbo in a different way.

DTI/DI - No Vacuum from BSCV (boost solonoid/control valve) = full boost
DTI/DI - Vacuum from BSCV = wastegate opened to lower boost pressure (fail-safe)

Whereas

ZTH - No vacuum from BSCV = vanes in bypass position (fail-safe)
ZTH - Vacuum from BSCV in various amounts = working vane positions producing varying levels of boost.

Ironically as i found when i had to move the vehicle around before i got the control system you will actually get 5-6 psi of boost on the DTI/DI control system as the maps meet there crossover points
However if you try to put the engine under any serious load the rising boost pressure when the map says it should be falling puts the vehicle in to limp mode (quite rightly)

So in order to control the system i have fitted a standalone model of the Digi-booster which is made in Scotland, Its a quite excellent device that allows you to control the turbo completely independently of the Vehicles computer (if it even has one)



The orange circle is on the vacuum line to the Actuator on the Turbo.

The green circle is on the green line that picks up the system vacuum (actually from the existing tee that would have powered the EGR solenoid)

The purple circle shows where the MAP sensor, EGR control Valve and vacuum tee are located under the intake pipe/wiring.

The red circle shows the Pierburg BSCV valve that came with the kit

The blue circle shows the little filter for the Atmosphere side of the BSCV just to make sure no muck gets in to it.


And out of shot is the controller itself.

Right that will do for now ill finish this in the morning.

Ok and now im back! last little bit to explain....

The Digi-booster unit i chose to use is a very flexible setup as you can make it as autonomous as you want.

https://www.tuning-diesels.co.uk/digiboosters/

You can give it its own MAP and BSCV and make it a total standalone controller or you can use the current MAP and also a throttle pedal signal to help the control system.
Ive had mine on the road for a couple of weeks and i am very impressed so far with just how much control it gives you, the turbo vane positions can be adjusted in 4 blocks of 4 different curves giving a wide spread o boost.
On top of this whichever curve you program then has an additional ceiling boost level chosen by a dial on the top right of the unit meaning you can for example have very quick boost build up low down on the rev range but also limit it to a relatively low max pressure if you wish.


(This photo is the property of Ronian the digibooster creator)

So far i have not used the TPS (Throttle pedal switch) input but i think i will later, as it allows both zero boost override at low pedal positions (mainly helping to save fuel on long journeys) and an over-boost function for high pedal positions, it should be noted that the over-boost function has its own separate boost limit that can be adjusted just like the main one.

When asking for one of these units i recommend speaking vie email to Ron who builds the units as he is quite happy to tailor the kit to your needs
For example i have retained the original MAP sensor and the Digibooster has a Tee wiring loom to go between the unit and the ECU.
Ron asked me about the boost levels i was going for, and as the build is my Daily work van i am not planning on going over 20psi.
He therefore has offset the boost levels that the ECU will see so that the 20psi of boost i want does not trigger an over-boost fault and limp mode.

Results of swap.

The main result of this swap has been a steady reserve of boost, i currently have a 16psi max boost at full throttle just on MAP feedback (no overboost or TPS) and though the turbo is not really any quicker at spooling than the previous turbo, the spread of boost once spooled is brilliant.
The previous TD025 mitsubishi turbo is a small unit and very fast at spooling (which is its job) but struggles to maintain boost over 2750-3000 revs.
It is not helped by the curious power characteristics of the Isuzu engine who's max power is very high in the rev range for a diesel in any case. With the ZTH turbo fitted the max boost i have chosen is very easily maintained up to and over 4000 revs if needed and once on song gives a very linear pull all though the gears.
Actual power increase as probably not as large as it feels as there is not much extra diesel going in to the engine, but combined with a fuel map i think this will be a very usable and tractable conversion for the DTI/DI.

I will keep you informed of progress as i go this winter will stay as boost only i think but if all goes well next year i may get a fuel map put on and see how the two interact.





Gratuitous pics of other parts i changed during the swap

Random pics that didnt really fit but might be interesting to some.






Interior of the TD03 showing the boost ring assembly which moves the vanes very slick setup in stainless to keep it working for a long time hopefully!








Hmm rear engined? or two engines?......nah.




 

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A very big welcome to the forum. A 1.7D Combo owner, in the NW, would be welcome enough for me but a top-notch write-up of an upgrade makes you even more :cool:

I have a Combo Tour, the previous owner did a Di-for-Di swap with a 60k engine which I have just had upped to DTi. The turbo on mine is good for a long while but I read this with a lot of interest. Your follow-ups (and how you think it's improved driveability) will be very keenly followed and I think (for the first time in ages, afaik) well worth me asking the admin to move into tutorial section. Are the pics saved well (some old threads with Photobuckets have dead pics, sadly)? I'll almost certainly save them onto my HD anyway.

Again, :applouse::yipee::thumbsup:
 

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Discussion Starter #3 (Edited)
Ta very much as i said at the start of the post there seems to be a bit of a lack of info on this which is a shame as once you have done it you realise there is very little to prevent you doing such a swap.
It also highlights how little GM changes certain things if they work well! IE the X/Y/Z series of isuzu designed engine blocks.

Would have loved a tour as i like having a rear door as a rain shelter at rally events!!
But all those i found for sale in this country are disabled converted and quite expensive for what they are, also such vehicles are rarely serviced well in my experience as they do less miles but sit around a lot.
 

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Won't hijack your thread, but yes - all the Tours in the UK are tailgate and wheelchair access (and expensive). Mine is lhd, first registered in Spain (where they're common as) and has the glazed rear doors (and, a shock for an old Spanish vehicle, service history).
https://www.corsa-c.co.uk/forum/showthread.php?522378-LHD-Opel-Combo-Tour-Payback-Time
is a thread on mine (I write too much guff but the pics are worth a flick) and Dan G has a glazed Crew which only really differs from mine in that the very rear "window" part on the sides is metal
https://www.corsa-c.co.uk/forum/showthread.php?522586-Combo-Micro-Camper/page3

The tailgate is good for rainy car boot sales but, tbh, I'd hate it in Malaga. Everyone parks right up to your sphincter and I'd never be able to open it up to shove stuff in (the boot, not my sphincter). I know Dan G considered the 1.9 and is thinking of zLET but I've become very attached to the Circle L. The IC has helped drag it into sub-glacial 0-60 and 20hp more would be welcome but otherwise I love its mile-pounding ability.

EDIT: ps, I read various "can I put an IC on my Di?" threads around the 'net but no definitive answer before I decided to go ahead. Pretty straightforward, really. Just to be clear; I saw a 130hp 1.7CDTi turbo and wondered if (supposing mine went suddenly flatulent) there might be some improvements and if it would work out - is this the sort of blower you're writing about?
https://www.ebay.co.uk/itm/Vauxhall-Astra-Corsa-Meriva-Mokka-1-7-CDTi-130-BHP-Turbo-Charger-789533/202771363646?ssPageName=STRK:MEBIDX:IT&_trksid=p2060353.m1438.l2649
 

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Discussion Starter #5
That turbo is from the DTR 1.7 A series diesel vaguely related but very different engine overall, its first gen meriva, combo c etc that ive used
 

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Discussion Starter #7 (Edited)
First Dyno run today.

3 runs all within 2-3 hp of each other.
very pleased with best run of:

95 Hp at the flywheel
and 159 lbft of torque

15.5 psi of boost
Peak boost reached at 2000rpm
and held till 4000 rpm


Previous to the engine swap it was:

76hp at the flywheel
and 139 lbft of torque

14psi peak boost
but boost trailed of after 2750rpm.


No fuelling changes have been made yet, this is all the VNT and boost controller.
So in that regard i am very pleased indeed!
Get more fuel in to it at some point and a little more boost and i think we will be in business.

we did try winding the boost up a bit (22psi) but with little result as there was simply no more fuel to burn.
so wound it back down to 15psi.

End of report!!
 

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Nice update. Hmm, ~100hp would be about what I would like to have available in mine; just for that 60-80mph blip to get past a lorry in the straight bit of a single-carriageway. Otherwise, I've been happy with just adding an IC. I did wonder if something similar to the CDTi (but without all the common railing) could be achieved, and now I know. As you say, from someone who stares in that bay quite a bit, indistinguishable from a std DTi.

Also, I should have noticed this in your first post but you spelled it out since, I definitely feel like I'm wringing nothing more out of mine by 3-4000rpm and I like the sound/data of your smooth delivery up to 4k. Nice purple pressure plate and springs, btw, a manufacturer thing or your own idea?

EDIT: Just realized you edited your opening post with updated info - thought I'd got Alzheimer's. Had a good look through the Digibooster site link; all very interesting.
 

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Very interesting. Apart from the times, something is very different to my std Di + IC (=DTi) set up. In mine, between ~3500 and 4k, really nothing extra is coming along and it feels strangled (and I held it at 4k too long, until I realized what wasn't happening). Yours is very definitely pushing on through that band, and you're able to change before 4k and stay in the zone, whereas mine seems to fall off quite a bit and needs to get its lungs back (on an incline, anyway - generally not too bad on the flat).
 

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Well this seems pretty cool! Do you have your old turbo? I'd like to compare my standard 35 for the td on the 1.7

Sent from my SM-A105FN using Tapatalk
 

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This is a great thread for you, DanG. Ferret's stuff interests the heck out of me, but you could actually contemplate doing these thangs. Apart from my griffin caps, if it's of any interest at all, the original (~200k km) Di turbo and manifold is sitting in my garage (a donor 60k mile engine was dropped in completely, I presume the previous owner thought it worth retaining).

Not a light piece to put a 1st class stamp on, but otherwise not of any scientific interest to me and you could finger it to your heart's content if that appealed.
 

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I love a good bit of fingering......

Iv just bid on a standard turbo so hopefully get that for a tenner, if not yea I'll get that fron you!

If I can get both manifolds side by side to compare that would be great. I mean I'd like to experiment on a none VNT turbo first on the 1.3. I'm currently looking for upgraded nozzles for the 1.3 injectors or altogether bigger ones but finding info online is proving a tad hard.

On a side note, iv just been given a spare 1.3 bottom end....... so in my eyes I con experiment with mine and push it until it blows and other than a quick swap who cares.......

Could also have some rods made up aswell I suppose

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Discussion Starter #14
The Dti/DTL Turbo is a Mitsubishi TD025 model, The VNT model i have used is in the TD03 family so just a bit bigger overall.

The manifolds are the same at the block but use different flange sizes and locations for the turbo's also the EGR port is in different places one each.



DTI/DTL




Gasket for either.





ZTH manifold.
 

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You possibly know this already, DanG, but have you rummaged through fora on the Fiat 1.3CDTi? Absolutely millions (literally) of the unit in India and lots of people who've tried various souping treatments and written about them (usually in English). Might get some ideas for things that do/don't work.
 
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