VNT20 Tips: Your Ultimate Guide

Hello everyone,

I'd like to know which VNT20 models are compatible with the AFN exhaust manifold (with adapter plate) for a Golf 3.
Are there different types of chargers?
Does anyone have part numbers?
Does anyone know which oil feed and return lines are suitable?

Which car does the turbocharger come from?
Can the original engine mount from the AFN model be kept (does it interfere with the supercharger)?


'Thank you!'

Regards,
DJ.

Which car does the turbocharger come from?


Hi.

VNT20 -> AFB / AKN.

I would like to know which VNT20 models are compatible with the (Golf 3) AFN manifold (with adapter plate)?


Okay, in terms of size, the loaders from AFB/AKN should fit; I even heard from someone who has one installed in a G3. It's recommended to use a support, as the VNT20 is quite heavy, and in the worst case, it could rip the mounting bolts out of the receiver.

Can you keep the original engine mount from the AFN (does it interfere with the supercharger?)


I can't give you a definite answer, but you should contact 'mozz' (I can provide his email address privately if you want, but I won't post a link here to avoid unwanted advertising). He has one.

Does anyone know which oil feed and return lines can be used?


same...

Hello,

Thanks for the answers so far!

There are several part numbers for the VNT20.
059 145 701 S
059 145 701 F
059 145 701
059 145 701 C, etc.

What is the difference?

Regards,
DJ.

Well, this has something to do with the endings. If it's like the standard 1.9 versions, you can roughly interpret it as an evolutionary stage (indicated by the letter).

matthiasTDI96 wrote:

Well, that's something about the endings. If it's like the normal 1.9 versions, you can roughly consider it as an evolutionary stage (indicated by the letter).

Well, I would say very roughly... that behind the letters, there are also the performance levels in a chaotic order.
Anyone who simply thinks "a higher letter grade means better" might end up installing a 100 horsepower turbocharger on a 150 horsepower TDI engine and won't enjoy it for long... but don't focus on that specific example, it's just about the principle.

Okay, purely theoretically, without any specific numbers, I think we can already say that the VNT20 likely wants to achieve quite high RPMs on an AFM (Air Flow Meter) in order to deliver its full power. Visually, it's a huge component and probably requires a significant amount of exhaust flow. After all, it's normally used to fire six cylinders. But let's wait and see what comes of it. Maybe it can all be properly tuned via the engine control unit. Just a small tip for the conversion: the V6 TDI engines typically have two intercoolers, or in the A6, a very large unit mounted on the water cooler.

Marco wrote:

Well, purely theoretically, without having any numbers, I think we can already say that the VNT20 probably wants to achieve quite high RPMs on an AFM in order to deliver its full power. Visually, it's a huge component and is likely to consume a lot of exhaust gases. After all, it normally feeds six cylinder bores. But let's wait and see what comes of it. Maybe it can all be properly tuned via the engine control unit. A small tip for the conversion: the V6 TDI has two intercoolers, or in the A6, a really large unit mounted on the water cooler.

Hi Marko,

The exhaust emissions for '150PS' should be the same for the 1.9L and 2.5L engines, so it should work .

Best regards, Rainer.

'Huh? Then I must have misunderstood something. With the same engine speed, the 2.5-liter engine has roughly 0.6 liters more displacement that goes to the turbocharger. Does that not make a difference? In other words, for me, it means that a higher engine speed is needed in the 4-cylinder engine to produce the same exhaust volume when using the same variable turbine geometry (VTG) control.'

Hi Marco,

Sure, it's true that it takes a while for the turbocharger to spool up. Below 2000 rpm, not much will happen, although you can achieve some improvements with the right amount of fuel and injection timing. However, above 2500 rpm, it should be almost effortless if the software is properly tuned.
For the same power output, the same amount of fuel must be burned per unit of time. Therefore, the same amount of air is required, and consequently, the amount of exhaust gas is also determined.
Overall, the build-up of boost pressure will naturally be more pronounced.

However, you don't need a VNT20 if your engine's power output is below 180 horsepower.

Best regards, Rainer.

Ideally, a hybrid turbocharger combining VNT20 and VNT17 would be used in the G3 engine, providing boost starting from 1800 rpm, with a potential maximum boost pressure of 2.2 bar relative, and a stable boost pressure of 1.9 bar.

Hi,

Thank you for all the tips!

I'm going to try it with an original VNT20, without the hybrid modification.
I now need to build an adapter flange for the 4-hole connection on the VNT20.
The AFN or SDI manifold (which apparently can be used for conversions) only has 3 ports.
At the same time, I need to figure out which cylinder head bolts (studs are too expensive) can withstand the high boost pressures.


Regards,
DJ1

Quote:

which cylinder head bolts (studs are too expensive) can withstand the high boost pressures.

Which cylinder head bolts (studs are too expensive) can withstand the high boost pressures.




hmm, yes I hear .
I think I need to use studs, right?

Take the AXG part and put washers underneath it.

Do the screws from the ARL not fit? I've been waiting for months for the studs, but mozz said they were already ordered. Now, at full power, it's blowing through at just under 4000 RPM.