GM Powered Mk4 VW Jetta

Hello everyone, long time browser of the GRM forums for advice on parts and builds. But now, I'm ready to dive headfirst into a project and could use the advice of other gearheads. 

The vehicle in question is a 2003 Volkswagen Jetta. Originally came with the 2.0L engine, which itself is a tank. What isn't a tank is the godawful "self aware" CAN system in the car, where if you blow a bulb out say goodbye to your ability to drive the thing. 

A little exaggeration but in all honesty, I've been dealing with CAN issues from day 1 of ownership and I'm sick of it. The motor, bless it's heart, is lackluster. So two birds one stone. An EcoTec 2.2 Swap. 

I plan on doing this whole thing in two steps:

Step one: Pull engine/transmission/engine specific wiring. Luckily VW has two plugs, one of which is strictly for engine/trans operation. Install EcoTec 2.2 and get it "running" in the car.

Step two: This is further down the road but I'm preparing for the inevitable. The CAN system won't like being able to see the engine, but it'll provide power to the rest of the car without it. I know this because, well, my ECM fried itself. Long story short, somehow a jumpbox took it out a few weeks after I used a jumpbox to get the old battery to O' Reilly's to swap it out. I did everything the VW forums told me to, including buying the $200 scan cable. Pretty much did nothing to help me in the end. So now I'm getting error codes for the ECM not seeing the engine, and the CAN system not seeing the ECM and Engine. It's a cluster and frankly, I have zero motivation to keep it as VW intended. 

Painless Wiring is local to me though, and so is Summit Racing. 28 circuit wiring harness and some interesting tinkering will get me where I need to in order to have the car's vital functions work as needed, and I have a fun little idea on how to make the windows/lock function without the CAN system. But that's way down the line. Let's talk about our main topic. The EcoTec swap.

====================================================================================

I'm no stranger to working on cars, nor am I a stranger to large projects. So I've been doing research and this is what I've come up with. 

Parts Needed:

EcoTec 2.2 L61 Engine (02-05 Saturn Vue seems to be the best candidate with a claimed 152hp)

Manual Transmission from 02-05 Cavalier/Sunfire (Cheap around my area)

GM P11 ECU (I've heard this is the most simple ECM to program, all it requires is a manual throttle body and some clever reprogramming to work in a "standalone" environment)

Engine Wiring Harness compatible with the GM P11 ECM

====================================================================================

So this handles the powertrain. Now we have the adaptability to look at. Here's what I've come up with. 

Spindles

- Spindles from a 02-05 Cobalt seem to be a great candidate for the CV Axles to fit like a glove. The biggest difference I see is the strut mounting and the lower ball joint connection. However with a mix of the strut mounts from a VW top to a Cobalt bottom, should have no issues. Fun fact, the spindles hold almost the same structural design between the two. The lower ball joint in the VW uses a traditional horizontal stud and nut setup. Cobalt's have the vertical bolt setup. Not sure what the technical term is, but both have three mounting bolts for their respective lower control arms. I'm sure with a little press magic or fab magic, the Cobalt ball joint can be made to fit the Jetta control arm. 

CV Axles

- The track width of a 2004 Chevrolet Cobalt is 58.7 inches, and the track width of a 2003 Volkswagen Jetta is 59.6 inches. This comes out to a 0.9 inch difference, or 0.45 of an inch on each side. With this in mind, depending on the mount locations I'd almost guarantee you could use the CV Axles and Spindles with minimal issue to get the swap started. Of course, a custom CV Axle would be more ideal in the long term but for now it would get the project "rolling". Pun intended.

Fuel Pump

- The Jetta's fuel pump access is directly underneath the rear seats. Simply remove the bottom of the rear seats and you're there. Both the 02-05 Cavalier and 03 Jetta have a removable fuel pump cylinder, and since both use the same plugin and have 2 spots for hoses I'd be willing to wager you could put the Cavalier fuel pump into the Jetta's fuel pump housing with minimal issue. 

Mounting

- This section is a work in progress, as I'm currently working on drawing up some prototype mounts comparing the mounting locations of both the EcoTec and the 2.0 8v. At the least, adapter plates. At the most, a completely new setup.

================================================================================

This is one hell of an introductory forum post, but I figured I'd share the idea with everyone as a bit of a psuedo-intro. Any advice you can offer on the EcoTec swap, programs to look at in order to tune the P11, etc. Feel free to post them here!

Id say skip the pump swap. Not enough difference in my mind to necessitate a bigger or different pump. Jetta will most likely gove more volume and pressure than the ecotec needs right out of the box.

In reply to Dusterbd13-michael (Forum Supporter) :

I may look into that, not sure what the pressure difference is between the two motors but I do think I can wire the Jetta's FP up to the Ecotec without any CAN interference. Thanks for the tip!

Yes, I would think hot-wiring the VW pump to operate from the GM harness shouldn't be too hard - especially compared to the rest of the swap. 

Should be an interesting project. I think you're crazy, but crazy around here is welcome.

I'm sitting here with a $600 VW Mk IV parts car in my back yard...  and wondering if it'd be possible to stuff a SBC and convert it to RWD in under a Challenge budget...  Unfortunately: no space and even less time to do much more than ponder the idea.

In reply to Ian F (Forum Supporter) :

I won't say it's possible, but I will say V8 Fiero is what you should start Googling :P

Blasphemy!  

Um...  Can I come over and help?

Bonus points if you make it a Smyth Ute at some point. 
 

edit: holy E36 M3. They have several new ones now. keep. Beetle. Subaru. 

In reply to OHSCrifle :

Funny you should mention that, I've already discussed the fabrication side of things with a buddy of mine who does great work. It's a little out of the budget at the moment, but it's definitely something I'd like to pursue.

Why not do a TDI swap with a mechanical pump?  Then no electronics at all as far as the engine goes.

In reply to zswildwasteland :

Oh I am very familiar with V8 Fieros.  I know a guy who builds them.  Coincidentally, his day job is owning/operating a German car repair shop and he also built a VR6 Fiero as well as a TDI Fiero.

Cool. Weird, but cool.

Do you know the spline count of the gm vs vw cv axles? It may be easier to use a vw outer on a gm inner or if the vw is the flat/winged flange style to use an adapter type stub shaft in the gm trans and use the whole vw cv axle/knuckle. My WAG is it'd be easier to adapt the cvs than attempt mounting the GM knuckle in the jetta.

Does the 6speed from the g6 bolt onto the ecotec?

oh man. Look for turbocharged Saab 9-3 with the ecotec (like 04-10 or so?). Manual trans available and sorta common, forged internals, built for boost, comes with turbo...

oh and did I mention they are cheap? here's one with 2 seconds of searching. 100k miles, 6 speed, $2500 ask

https://chicago.craigslist.org/sox/ctd/d/robbins-2003-saab-3-vector/7339952712.html