2011 Audi A4 B8 - ALH TDI Conversion


Veteran Member
Jan 31, 2007
2011 Audi A4 ALH TDI
This car was intended to serve one purpose. A reliable , AWD commuter, that maintains excellent fuel economy.
Living at a higher elevation with snow and leaving early for work before the plows come means our 2000 Jetta TDI is not the right tool for the job. (Abandoning it at the bottom of the hill sucks)

So, we bought a cheap cheap 2003 golf a few years back with the intention to convert our Allroad to a tdi. That didnt happen.

Fast forward to now. We found a 2011 A4 AWD with a blown motor for a smokin deal. Without a conversion anywhere on the internet to be found, we went ahead and winged it. haha

This project is a budget project, and we re-used most of the 2.0L bits and pieces (mainly hoses, sensors, etc.)

I cannot break everything down step by step, but will give an outline of some of the challenges we faced, European parts we needed, and general modifications.

Disclaimer. You do require some fabrication skills , mainly engine mounts/downpipe/intercooler pipe etc.

Here goes with some highlights/issues we had to overcome:

-Flywheel bolt pattern. We re-used the 2.0t flywheel. (YOU HAVE TO ) It fits perfectly onto the alignment hub on the alh crank. It was 8 holes, the ALH is 6. We welded up holes, and drilled new pattern to fit ALH crank, then put it on a lathe.

-Starter . The 2.0t starter is not large enough. (it wont live long turning the diesel engine over . Had to import a 2.0 diesel starter from a b8 tdi from europe. (pic below for size comparison)

-Turbo. The ALH turbo interferes with starter. Therefore you need to source a longitudinal turbo from passat / audi diesel.. Bought a 1749VA from europe to make it work.The turbo also puts an almost perfect placement for a straight downpipe to existing 2.5" exhaust system ;)

-Intake. ALH Intake inlet facing the wrong , not enough clearance for intercooler piping on the front of the motor. Bought a PD130 intake from Europe. Works great, and much larger/better flow.

-Custom Fabricated engine mounts to utilize the OEM rubber mounts. Used steel solid stock, drilled and tapped to maintain stock rubber mounts/hardware. Also required for starter/turbo clearance.

-Power steering line welded to alh bango to utilize alh PS pump. Works fine.

-90% of the coolant lines were plumbed using 2.0t and ALH donor lines. (very little $ spent in this area. Made a hose reducer and integrated the 2.0T coolant temp sensor to maintain control of the dash. Coolant temp on dash works.
Retained factory radiator, and reservoir.

-Tach signal: 2.0t reluctor wheel which was on the crank internally, removed, and welded to the front crank pulley. Perfect match for the outside circumfrence of the crank pulley which allows for perfect alignment for welding. Made bracket to mount externally and utilized 2.0t factory crank position sensor.. Tach signal works..

-Speedo still relies on Left front ABS , still works never touched it .

-Oil pressure sensor works, 2.0T plugs right in. (same sensor) Dash works

-Oil pan. ALH will not clear PS rack. Had to replace with 1.8T oil pan & pu tube. Factory 2.0T oil sending unit bolts to the bottom.

-Factory airbox retained. Modified oem MAF housing to accept ALH MAF. ALH MAP sensor bolted right into the place of the 2.0t location/existing intercooler piping.

-Turbo outlet to the intercooler piping was retained by using the ALH pancake pipe quick connect hose. Used hose joiner to connect to 2.0t intercooler.

-Factory front mount Intercooler stayed OEM. The piping up top made with 2 1/4" exhaust tubing and rubber factory elbows from the 2.0t. The theme in this swap, re-using alot of 2.0t stuff.

-Fuel system plumbed into the existing lines with some small modifications at the sending unit where the pump was bypassed. Made quick charcoal cannister bypass with piece of 3/4" hose

-Throttle pedal from ALH was bolted to the Audi, but had to change the angle of the pedal -cut and weld(see pic below)

-Factory ECU left in place. Removed all non-used engine sensors and dead headed the wires.

-Utilized TDI Alternator, only 1 wire from Audi side, plugs in for the dash light. (works)

-TDI Harness stripped to just whats required to make engine run (stand alone) Immobilizer , EGR and ASV deleted from ecu. Malone tuning.

-Engine runs by itself, engine vitals monitored by original Audi sensors & work in dash.

-ABS and Quattro system functionally well.

-CEL on. (Shocker)

-Stability Control Light on because throttle body isnt hooked up, it cant kill the throttle . ( not that we care) lol

-No cruise control, haven't tried to figure that out yet.

-Complication. Both cooling fans are runing all the time as soon as you fire engine up. (working on fixing that quernk)

-Still have to make custom AC lines to ALH compressor.

-E brake fault warning. But E brake still works. Because factory design will automatically release the ebrake when you give it throttle. Factory throttle input not connected.

Everything in the rest of the car functions (Interior functions/ Radio/ Heater/ dynamic steering, etc. is happy)

Mods on the TDI include an old school tuning box and TPC for proof of concept. May consider getting ECU flashed. PD130 intake and vnt 17

Car is not disappointing to drive at all. Very impressed with overall road manners, Gearing etc.

Clutch and 6spd manual Trans feel great.

Worth the effort. Alot of head scratching, and thinking outside of the box .

This swap is function over finish, but the end result was we made the swap work with $1500 (including $400 parts car) Utilizing existing parts was huge, shopping ebay etc...

Now we want to find a b8 Avant. :)

Flickr has the photos. Too painful to upload here.


thumbnail_image1 (1) by drkblujetta Smith, on Flickr
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