Ok, so there seems to be a ton of misinformation out there regarding the TDI motors and swapping them. I'm here to set this straight! I own a TDI specialty shop and have been working/modifying/swapping them for 7 years now. I've been there and done that with just about every avenue regarding them and will try to share my knowledge. I'm not going to discuss the IDIs are I feel they're barely adequate for a lawnmower on a good day with a hurricane tailwind.
List of basic motors that are out there that are good for swapping.
This is my personal favorite, basically the 4bt of the VW world. Simple and best bang for the buck to modify. Can be brought up to a reliable 200hp/350tq with bolt-ons, 275hp/450tq if you want to delve inside. ALH was the first diesel of the new engine block design that did away with the intermediate shaft and external water pump. Uses many fewer gaskets so generally much lower tendency to leak oil. Easy to recognize by cast aluminum valve cover held with 5mm Allen perimeter bolts. If you can, get the motor (or at least the injection pump) off of an automatic car. Auto cars had 11mm plunger pumps, manuals had 10mm plungers. These motors have VNT turbos that are mounted on a turbo-fold. Kind of a pain for starter clearance on passenger side starter swaps. The easy solution is to get a 04-05 Passat TDI manifold & turbo (small upgrade from stock ALH turbo) or any of the aftermarket 8 valve 4 cylinder exhaust manifolds on e bay and put on a bigger turbo (you know you want more power). Either of those manifold options will pick the turbo up and away from the motor giving you more clearance for starters.
The wiring on these may look somewhat intimidating at first to those that aren't electrical friendly, but once you get it, it's extremely simple. The ECU for these is also much smarter than the older ones and is OBD flashable with a loader. Once the immobilizer is deleted by a tuner, there is no need to use OEM key, cluster, or any of that crap. I can't even say how many people I've seen go through the hassle of trying to hide an OEM key and cluster because so and so told them there was no way around it. Total BS there.
Many more updates will be added over the next few days. sleepy time now. Stay tuned.
List of basic motors that are out there that are good for swapping.
- AHU/1Z - These are found in 96-98 Jettas and Passats. These are the old-style blocks with an intermediate shaft and external water pump that are basically the same from the mid-'70s till 98. Easy to recognize by stamped steel valve cover with 3 bolts in the center holding it down. They come with a wastegate turbo that's the size of a pop can. The wiring harness is very simple and the ECU doesn't have an immobilizer. However, to tune the ECU it needs to be socketed and burned chips installed. Not a huge deal for any tuner, just an added annoyance IMO. They can be converted for VNT turbo operation by a vent-specific ECU tune and a 00-03 N75 turbo solenoid valve. Extremely worthwhile if you insist on using this motor. The main drawbacks to these motors are: slightly poorer flowing heads than later motors, the tendency for oil leaks, 80kmi timing belt intervals, accessory bracketing sucks, and the ECU is rather dumb (think dos vs windows 98). If you're not planning on much over 150hp and you get one for cheap, they'll serve you well enough. If you want lots of power, skip to the next options.
- ALH - Found in 00-03 Jettas, golfs, and beetles. Technically ALH's were available in beetles from 98-03, but the 98-99 beetle ECU/harnesses are bastard child and totally unique. Trust me when I say stay away unless you get them for free, in that case, sell them for a 00-03 ECU/harnesses. You'll thank me later.
This is my personal favorite, basically the 4bt of the VW world. Simple and best bang for the buck to modify. Can be brought up to a reliable 200hp/350tq with bolt-ons, 275hp/450tq if you want to delve inside. ALH was the first diesel of the new engine block design that did away with the intermediate shaft and external water pump. Uses many fewer gaskets so generally much lower tendency to leak oil. Easy to recognize by cast aluminum valve cover held with 5mm Allen perimeter bolts. If you can, get the motor (or at least the injection pump) off of an automatic car. Auto cars had 11mm plunger pumps, manuals had 10mm plungers. These motors have VNT turbos that are mounted on a turbo-fold. Kind of a pain for starter clearance on passenger side starter swaps. The easy solution is to get a 04-05 Passat TDI manifold & turbo (small upgrade from stock ALH turbo) or any of the aftermarket 8 valve 4 cylinder exhaust manifolds on e bay and put on a bigger turbo (you know you want more power). Either of those manifold options will pick the turbo up and away from the motor giving you more clearance for starters.
The wiring on these may look somewhat intimidating at first to those that aren't electrical friendly, but once you get it, it's extremely simple. The ECU for these is also much smarter than the older ones and is OBD flashable with a loader. Once the immobilizer is deleted by a tuner, there is no need to use OEM key, cluster, or any of that crap. I can't even say how many people I've seen go through the hassle of trying to hide an OEM key and cluster because so and so told them there was no way around it. Total BS there.
- BEW - These are found in 04-05.5 Golfs, Jettas, and beetles. These are unit injections, with no external injection pump. Same short block as an ALH, just a different head. ECU/harness on these is very similar to the ALH once stripped for swap use and immobilizer deleted. The only major issue with these (and any of the unit injection motors) is that the cams are ground wrong from the factory with incorrect geometry. Somewhere between 50K and 150K, the cam and lifters will need replacing. The good news is a few years back I worked directly with Colt Cams to develop fixed profile cams that don't eat themselves. The bad news is because the cam is billet steel, it isn't a cheap job. A cam kit with cam/lifters/bearings/gaskets is $920. However, these motors are very quiet and smooth compared to the AHU/ALH. Power potential with these is just as good as the ALH, just more expensive to upgrade injectors on these vs the earlier rotary injected motors.
- BHW - Found in 04-05 Passats. These are the most powerful factory TDI motor offered in the US at 135hp/236tq. With just a tune these jump to 170/325. Also the only factory longitudinal motor so accessories and oil pan are much more suited for longitudinal swaps. They also have a more traditional turbo/manifold setup that puts the turbo up much higher than any of the first 3 motors talked about. The turbo is also 3mm larger, and will make about 20hp more than stock ALH/BEW turbo. These are basically the same as a BEW with slightly larger injectors, 81mm vs 79.5mm bore (these are a 2.0L instead of a 1.9L), 2mm larger rod journals, and 1 point lower CR. With the bigger rods, these will hold 240whp on stock internals without ever taking the head off (~275hp with a ported head), just a $200 set of arp studs for cheap insurance. The downside with these is they have the same cam issues as BEWs. One other unique item these have that must be addressed is a chain-driven balance shaft module that bolts to the bottom of the block. It's a piece of epic fail that you need to toss in the scrap bin. The normal oil pump and chain drive from an ALH/BEW bolts right on and fixes that clusterfook. I'll post PN's for that later on.
- BRM - Found in 05.5-06 Jetta and beetle. VW's next block architecture design with a $120 rear main seal. It's basically a slightly updated BEW with a high mount turbo and more EGR bs. I would suggest avoiding it unless you get it dirt cheap as it is a unique wiring harness/sensors. The ALH/BHW/BEW share many of the common maintenance items that are much cheaper. These also are unit injections and have the same cam issues.
- CBEA - Found in 09-12 jetta and golfs. These are the latest and greatest common rail, DOHC motors chocked full of emissions garbage courtesy of uncle sam. Great platform for power once "fixed", but still too expensive/complex for mainstream swaps just yet. I'd suggest sticking with one of the older motors for a few more years. I'm putting one right now into a race car at work, but the budget is of no concern when the customer is some hedge fund manager. Must be nice
Many more updates will be added over the next few days. sleepy time now. Stay tuned.
