Need someone to talk me down, VW engine swap and standalone ECU content

Hypothetical situation.

I have a '72 Beetle with a '91 Subaru engine, using stock transmission. Engine has chronic overheating problem, suspect bad head gasket and/or warped heads.

I also have a 2001 VW Passat with the 2.8L 30V V6 and a 5 speed transmission. Needs a clutch. Blue Book value is so low, it's not worth spending the money to replace the clutch.

I could mid-mount the V6 in the Beetle, using the Passat transmission (replace clutch and use longer shift cables). I'm leery of the wiring; paring a newer stock harness down for just-the-bare-essentials use is doable if you have a recipe to follow, but I have found that it's a pain in the ass to break new ground. So... standalone ECU (MegaSquirt?). What would I need as far as wiring/electronics?

Would cost about $300 to do the head gaskets again, and this is on the 250k+ mile Subaru engine (and the way I beat on it, its probably about due for a full rebuild). If I could get a 50% hp/torque increase with the VW engine for less than $1000, I might seriously consider that.

So you want us to suggest you not put the Passat engine in your bug, in the wrong orientation from original, because the wiring might be difficult? You realize you came to enablers-r-us right ?

I'm very much liking your SubaBug!

Since I believe all of my vehicles have a blue book value around scrap, I'd do the clutch, drive the Passat for another 100k, and either grab another Subaru engine off CL or rebuild the current one.

It's been a long time since I've done anything with a Bug, but isn't there a crossmember holding the torsion bars just in front of the trans? If you have the fab skills to make it happen, it would be a pretty cool project though!

I would verify that the 91 Subaru engine has a bad head gasket, and/or warped heads. But chronic overheating does sound pretty bad. As for the Passat engine swap, can't you buy or make covers for the wiring harness sections that you won't use?

Id buy a slightly better subie engine. Less things would have to change. Maybe upgrade the radiator a bit.

Also I helped build a 20b turbo 911, one of the older 70's chassis with widebody and such. We took an rx7 radiator and cut it in half and put it in the wheel wells in the front in addition to the radiator in a "normal" spot that was put there by the previous owner. It didnt have space for air to flow out though, so we made a nice path for it to exit and go under the car and put appropriate fans on all radiators. Plus nice feed/return tubes back to the engine all fed by a standard FC water pump (better than FD pump) not an electric pump. This car did make 702rwhp on 91 octane with meth injection. Bad ass car. Way too much work and lots of sacrifices to the German car gods, to exorcise the old wiring with new functional stuff.

A really nice setup to remove air bubbles helps. A lot.

Not that I'm saying you need 3 radiators, but a good one with proper airflow and air separator tank will go a long way to help keep overheating at bay.

XLR99 wrote: I'm very much liking your SubaBug!

Me too. That's cool!

More pics? How's it handle. Seems like it'd be fun in the auto cross.

Fix the Subi, you can always boost it

01 Passat on Megasquirt it pretty easy. Microsquirt to do it on the cheap. Hit me up for specifics but I can mod/base config one for 450 shipped for almost any vw/audi.

Enablers. The lot of us.

Are there mounts to the transmission for the VW. For the cost of a Kennedy mounting it you can get a complete Subaru motor and do preventive head-gaskets and studs and drop it in say in 5 hours.

You could not pay me to use the VW stuff.

Rustspecs13 wrote: Also I helped build a 20b turbo 911, one of the older 70's chassis with widebody and such.

Please tell me you have pictures of this.

What I would wonder- what would you have to cut up to make it fit? And by cutting it up, what of the car's usefulness, are you going to have to give up?

Not just for the car, but also for the cooling system.

If you can deal with that, go for it!

Putting the VW V6 in the Beetle would be expensive and time consuming in during a year I won't have lots of time. I'll probably wind up doing the head gaskets again once I confirm that there are exhaust gasses in the coolant.

The Subaru engine in current configuration normally runs at about 190 degrees F. The fan kicks on when it needs to, the thermostat opens when it should. I spent two hours attempting to adequately burp the system (which has several high points with bleeders to remove air pockets). Would get to the point that only coolant was coming out of the bleeders, but built up more air pockets the longer it sat running. Higher RPMs meant more air. Just replaced the head gaskets a couple months ago (less than 500 miles), and admittedly kind of rushed it. Probably poorly installed the gaskets, though I didn't have the heads checked either.

Hypothetically, I would mid-mount the V6, which would mean lopping the transmission mounting "horns" off the back of the frame and building a cradle for the engine and trans. Would lose the entire back seat. Either a front mounted radiator like I have now, or a larger one mounted at an angle inside the current engine bay, above where the V6 transmission would sit. So, I'd have to sacrifice any hope of using it as a hauler of people, dogs, luggage, etc. Not that it's particularly good at that now.

More pics here. Roadtrip thread from last summer. It's a hoot to autocross. Suspension is pretty stiff. Engine swap puts it in SCCA XPrepared class, where it is laughably far from competitive. Understeers a bit on throttle, oversteers with trail braking. Pretty predictable. First event was today, and I am genuinely bummed out that she was out of commission.

Have considered boosting too, but figure a full rebuild is probably in order before then, to include rods and bearings. Assuming I'd need a different computer setup as well...

putting the V6 would be an exercise in a lot of work for a little loss in power compared to what you could get out of the Suby unit. All the strength in the bug is in the pan, so if you cut it to mount an engine in the middle of it, you are going to get a very flexy flyer.

As for the reliability of VW units themselves.. I think the actual hard stuff is pretty durable, it is all the electrons that constantly want to escape and wreck havoc. It's hard to tell though, not many people can keep a VW running to the point of wearing out the engine