Do you know how many CFM those fans are capable of? That’s probably the most important consideration. If they’re not capable of at least 2,500 CFM or so it may not be enough.
Do you know if they’re a single speed, 2 speed, multi speed fan?
On a 2008 VW the fans are likely controlled by the ECU. That doesn’t mean you won’t be able to control them with a thermostatic switch, but you’ll have to figure out how to handle the switching. Also, if they’re a multi speed fan and you want them to operate that way, you may need to figure out how to wire the resistor that was originally used to do that. Or use a digital fan controller like one from Dakota Digital.
I run a Ford Contour dual electric fan set up in my Duster, it’s a 2 speed fan and I control it with a Dakota Digital controller that lets me program the on/off temperatures for both fan speeds.
The size of the engine isn’t the most important factor. The horsepower rating is a better judge, because that’s more closely tied to the amount of heat being created.
The other thing is, modern engine bays are much tighter and modern grilles are frequently smaller, so, the fan requirements are typically higher for a modern engine even if the displacement is much smalller.
The Ford Contour fans are a good example, they’re for a 2.5l V6. But I’ve never had an issue with them cooling my 400+ hp 5.6l, 340.
