AMF VNT Turbo

Dblock

Dblock

Member
Hi guys,

I'm preemptively looking for a turbo for my car. It's not on it's way out yet but when it is instead of going standard I'd like to upgrade. Now I could stick a bigger turbo in but then the problem is that you get more lag and generally the power will surge later in the rpm range. Hybrid turbos are expensive and can still suffer the same problems but less so usually. So best of both worlds are VNT turbos or like the ones you A2 90ps owners have. ATL engine code I'm sure. You can have a bigger turbo with less lag due to the better design.

So has anyone been able to fit any VNT turbo onto a AMF 75ps 1.4 tdi car with the VNT being controlled? i.e it working like it would in the ATL 90ps engine?

Thanks guys :cool:
 
Interesting idea but I don't recall anyone having done the conversion. Maybe Vince at Stealth Racing could advise if the TDi 90 ECU could be made to work on the TDi 75 engine using the VTN control hardware from the 90.

Cummins truck engines with VTN turbos just have a signal line from the intake manifold direct to the VTN actuator capsule so the vanes vary with turbo boost pressure. It may be possible to do something similar on the A2 but the TDi 90 turbo would need a different capsule as the standard one works on vacuum and not pressure.

Cheers Spike
 
spike said:
Interesting idea but I don't recall anyone having done the conversion. Maybe Vince at Stealth Racing could advise if the TDi 90 ECU could be made to work on the TDi 75 engine using the VTN control hardware from the 90.

Cummins truck engines with VTN turbos just have a signal line from the intake manifold direct to the VTN actuator capsule so the vanes vary with turbo boost pressure. It may be possible to do something similar on the A2 but the TDi 90 turbo would need a different capsule as the standard one works on vacuum and not pressure.

Cheers Spike
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Thanks for the info. I read but it was of dubious quality that the n75 controls the vnt with support from the ecu and apparently the ATL map can be put straight onto a AMF car which I don't know about.
 
Just realising how little I know about the 90 TDi turbo.
If turbo boost is only controlled by the VTN capsule compared to the normal (AMF engine) turbo which has the wastegate capsule, then its likely there is a reasonable correlation between the VTN and wastegate signals. If the N75 valve set-up is the same and the ATL map can be transferred then there is a fair chance it will work.

Well done for the nice bit of research.

Cheers Spike
 
spike said:
Just realising how little I know about the 90 TDi turbo.
If turbo boost is only controlled by the VTN capsule compared to the normal (AMF engine) turbo which has the wastegate capsule, then its likely there is a reasonable correlation between the VTN and wastegate signals. If the N75 valve set-up is the same and the ATL map can be transferred then there is a fair chance it will work.

Well done for the nice bit of research.

Cheers Spike
Click to expand...


Spike your a knowledgeable chap from the sounds of it. I like that. It was from dubious sources but I will be researching further hopefully.
 
spike said:
I didn't realise the exhaust manifold was integral with the turbo housing.
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Spike,

They are most definitely separate components. They are probably offered as one lot as they are sometimes difficult to separate because of seized nuts. You usually have to resort to a nut splitter.

RAB
 
RAB said:
Spike,

They are most definitely separate components. They are probably offered as one lot as they are sometimes difficult to separate because of seized nuts. You usually have to resort to a nut splitter.

RAB
Click to expand...

I'm wrong! On the ATL they were integral.

The terms VNT and VTG are more about trade marks than anything else. Garrett used VNT and Borg Warner VTG. They are fundamentally the same. VTN is only used (mistakenly) on forums!

RAB
 
RAB said:
The terms VNT and VTG are more about trade marks than anything else. Garrett used VNT and Borg Warner VTG. They are fundamentally the same. VTN is only used (mistakenly) on forums!

RAB
Click to expand...

Hi RAB

Not sure if all turbo companies stick to the same nomenclature but generally the VTG has vanes which pivot on a centre pin and vary the angle of attack of the airflow in the compressor housing.
VTN has vanes (fixed onto a backplate) which slide through slots in the housing. The blades move in and out, varying the amount of blade protrusion and changing the airflow characteristics in the compressor housing.

Cheers Spike
 
there's essentially a couple of bits with a guy whose turbo recently died. There's a bunch of links to turbo shops / repairers, the like of which I haven't seen before, including replacement prices (which are all around €800, BTW, with €100 on the old part). The other comment that's extremely pertinent is the one that says you should change the oil feed line when you replace the turbo, and probably anyway, because that's the one that will get clogged.

- Bret
 
bretti_kivi said:
there's essentially a couple of bits with a guy whose turbo recently died. There's a bunch of links to turbo shops / repairers, the like of which I haven't seen before, including replacement prices (which are all around €800, BTW, with €100 on the old part). The other comment that's extremely pertinent is the one that says you should change the oil feed line when you replace the turbo, and probably anyway, because that's the one that will get clogged.

- Bret
Click to expand...

Thanks for the summary

Cheers Spike
 
spike said:
VTN / VTG. Yes, we are guilty of the sloppy use of terminology for two turbo designs which do similar things but in a slightly different way.

There is a 90 TDi turbo on e.bay - http://www.ebay.co.uk/itm/Audi-A2-1...di|Model:A2&hash=item27d9cb0713#ht_1553wt_952

I didn't realise the exhaust manifold was integral with the turbo housing.

Cheers Spike
Click to expand...

Not cheap but if it was to work properly well worth it I'd imagine. Still looking into how to get the VTG/VNT turbo working though.
 
spike said:
Not sure if all turbo companies stick to the same nomenclature but generally the VTG has vanes which pivot on a centre pin and vary the angle of attack of the airflow in the compressor housing.
VTN has vanes (fixed onto a backplate) which slide through slots in the housing. The blades move in and out, varying the amount of blade protrusion and changing the airflow characteristics in the compressor housing.
Click to expand...

Hi Spike,

I have Garrett (VNT trademark) turbos on all three 1.2's and they definitely have vanes which pivot on a centre pin and vary the angle of attack of the airflow in the compressor housing, as you describe!

RAB
 
RAB said:
Hi Spike,

I have Garrett (VNT trademark) turbos on all three 1.2's and they definitely have vanes which pivot on a centre pin and vary the angle of attack of the airflow in the compressor housing, as you describe!

RAB
Click to expand...

Nice one. I think we should re-name this thread................. MYTHBUSTERS

Cheers Spike
 
A quick question does anyone know if the VNT and manifold from the ATL will fit the AMF or does it need a custom manifold?

Thanks
 
The word is that you can cut off one exhaust manifold branch on the 4-cylinder manifold - and the resulted 3 brach manifold will bolt right on to 1.4TDI. Naturally the deleted branch has to be welded shut.

I have heard through a set of friends that one such installation has been done here in Finland.
 
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