Originally Posted by Hodakaguy
The H6 is a great engine, love the Timing chain, no head gasket issues and a boat load of HP/torque....but
The H6 is a lot of power for the stock drive train and will eventually cause problems if you dont spend some money beafing up the trans, the vanagons gearing is also poorly suited to the H6....more money on a re-gear. My friend has a H6 powered Westfalia, on a recent 400 mile road trip he averaged 13.5MPG...Yikes! The H6 is also more expensive to install (you need a $2k link ECU) and your very limited on exhaust choices etc.
The 2.5L will almost double the Hp of the stock engine (90hp to 170hp), with a 16" tire upgrade it's well matched to the stock transmission ratios and doesn't put the stress on the drive train that the H6 will. With the 2.5L you'll get 19-20MPG All around the 2.5L is hard to beat.
My friend with the H6 is going to remove his and install a 2.5L or a TDI in the future.
I was thinking the tranny might be the cause...
But the other stuff on top of that makes it sound like it was an easy choice...
Looking forward to reading more...
On TDI: A guy I bought some MKIII parts off of was planning on dropping the TDI in his Vanagon (non-westy)... He seemed like he was a little crazy... which you might just have to be...
Should make similar tq to what you are talking about given it was an older TDI