Update: Made some progress since the last update. We've put on about 16,000 miles since the swap and should have about 20,000 on it by the time the first year mark rolls around. Long term our warm weather mileage had been averaging about 35 - 36 mpg and winter mileage at 32 - 33 mpg. Still working on getting full operating temps out of this thing - takes about 15 min in hot weather and never in cold weather to reach operating temps with a fully blocked radiator. Changed the thermostat twice, so I don't think thats the issue. I'm thinking now that the rear heat in the van has got to go. I think the 20 + feet of exposed heater lines under the van and the rear heater core are bleeding a lot of heat - more heat than this tdi can handle. I've got a ball valve and fittings sitting here to shut it off and to see what happens. I figure this temperature issue has got to be hurting my mpg a fair amount.
On the positive side, my vgt turbo that has been stuck for a long time just became unstuck several weeks ago (Stuck half open making it sorta drive able hence the
stuck for a long time). My wife was driving on an interstate and blew an intercooler boot and said when it happened it let out giant black cloud. I've never heard of a stuck vgt freeing itself, but hey, in definitely NOT complaining - saved me a lot of money and trouble. It now has normal power throughout the rpm range when before it was dropping off significantly on reaching 2700 rpm.
We just replaced the exhaust two weeks ago with a real system - the temporary flex pipe I used to hook it up during the swap broke off at 3 feet long. Note to self - if you want people to notice you have a diesel/5spd minivan, run said van for a couple weeks with 3' of exhaust attached.
The guy at the exhaust shop said it was one of two minivans he'd seen that could be considered cool.
We also got the first tank of fuel done with the unstuck turbo and the smaller tires. I found a set of two used smaller tires that changes my gearing close to where the Jetta was originally. I don't have hard numbers, but it is noticeably easier on the clutch to launch it, accelerates better and hold interstate speeds better. First tank through was 39 mpg!
(705 miles total with about 100 miles freeway driving)
Now if I can just get around to replacing the worn out injectors.