Build Thread: Cactus Green B5 V10 0A3 Avant

The Goal: find one of the 241 B5 Cactus Green avants brought to the US, and drop a 5.2 in it with R8 headers mate it to a 6spd 0A3 trans .

WHY? I’ve landed on this goal based on my experience with German cars so far. The specialty OEM colors of the 90s and 00s have always been cool to me. They made a zillion silver B5s so colored ones stuck out. I swoon any time I see a green SQ5 and set my sights on finding a Cactus Green car next. I love the 2000s VAG because to me its the correct size vehicle. Every year cars grow in size and weight and to me its unnecessary. B5 seems to be the right size. After having the C6 S6 I was sold on the V10. Theres still great power by today’s standards. It is obscure (to most) and has a lot of unlocked potential. I am comfortable working on it. Next, what better combo than a V10 with a manual?? The common swap seems to use 01E but forums have convinced me an 0A3 is just as capable of holding the power, and giving a better driver experience. And finally, why Avant? The wife said she wants a station wagon :grin:

  • My 1st VAG car was a MK4 New Beetle 1.8T - cut my teeth on this mechanically as a teen. Light and fun. Went to SoWo a few times, got in the “scene” I was hooked.
  • 2nd VAG was B8.5 S5 - Full bolt ons, fun but didn’t like paying $4k to fix my Electromechanical Steering rack.
  • C6 S6 - Fell in love with the BXA 5.2 sounds, but its a big boy and the transmission/cats…we all know they’re castrating. Once I saw what Joel and Martin were doing with these engines in smaller chassis I knew that was my next move. Took me a few years but I’m finally here.

Sold my C6 S6 at a premium $14,000, and started searching for parts/donors. I got 3 leads on cactus avants, and one great package deal that ended in the seller backing out. Found an 0A3 with a cracked bellhousing for $100 locally. Will have to TIG it back together then it’ll be mint!

Acquired the R8 Headers! Also got a B7 S4 rear timing cover and 5.5mm OEM spacer. Martin got me a set of manifold flanges to weld on when I get there. I think a big hurdle I am willing to take on is his comment about these not fitting in the B5 frame rails. I believe the ID of the rails is 25" and needs to be 32" for a correct fitment. Maybe some tube rails are in the future?

Found a donor facelifted S6 in the hills of Vermont. 179k and in rough shape. He backed over a 5 gallon bucket of white paint on the passenger side and it has leaked oil since. He said that was a few months back and he’s had it parked since the incident. We agreed on $2500…Not bad considering the original post was for $12,900. I drove it 300 feet, it pisses oil. Suspecting the oil cooler got jacked as its in that general location. Time to part out and pull the motor.

I’m all for this! If you wanted to settle on a sedan my dad has an absolutely mint Cactus B5 S4!

I’m excited for this!

1 Like

WOW looks super fun. The classic look of the B5 with a real motor. In for the fun.

1 Like

If I have this motor and trans fully prepped before I find an avant, I’ll may go for it. But really trying to make no compromises on a project for once. Easy to say at 10% into a project :laughing:

Got a good amount of buyers on the partout. Feels good knowing the whole thing isn’t going to the scrap yard and some of its harvested organs can live on to keep other C6’s road worthy. Over the weekend I stripped most of the interior and front end. This exposed a little more on the eninge oil leak. PO lived on a sandy dirt road driveway so all that shit is everywhere on the car, except around the oil cooler.

A fewareas of concern I found were a split vacuum line and a totally rotted subrframe. There’s no way this would have lasted on the road. Vacuum line just a sign there’s probably a lot more leaks I can’t see.

Got a good amount of the engine harness looms disconnected. A few pesky hose clamps but no broken connectors so far knock on wood. Hoping to have powertrain separated by end of next weekend.

Powertrain is out! That was shockingly smooth. Next week or so I plan on getting the shell out of the shop and into the yard, and getting the engine/trans into my garage (across the street). I’m trying to ponder up a good engine stand or workbench I can have the 5.2 and 0a3 on through the winter. I plan on doing timing chains, carbon clean, head gaskets and other general maintenance. Anyone have suggestions? A hydraulic table like this is my best solution so far.

Those are stupid cheap, they look lower profile than the ones I have

After hunting down and pursuing nearly a dozen cactus avants the last few months, I think I secured a swap candidate. More to come in the next few weeks.

Made some progress today. Managed to take an air chisel to a few pesky exhaust manifold nuts. That revealed some battle wounds from its past…possible a separated CV at high speed? Literally punched through the subframe!

Got the engine mgmt harness out, thatll be fun to bench clean!

Trans removed from engine, big progress! Need to take some measurements for custom engine cart. Can’t decide weather I should mount it on a stand with motor mounts, or put mounts directly onto the block. Thoughts?

Got the engine mounted onto my cart with some fabbed up square stock mounts. I’ll have to redo the back one when the 0A3 joins, but some maintenance to be done on the engine before we get there. Flying out to pick up the donor car Wednesday, and then proceeding to drive it 1200 miles home. Wish me luck!

Awaiting pics on that Cactus bro!