Subaru H6 3.0 or 3.6 motor mounted on T3 standard auto tranny

[ischias]

Hello.
Does anyone here, have some info if this is possible?

Can you mount the Subaru H6 3
0 or 3.6 motor on standard VW T3 autotran?

If so, who sells the adapter for this?

Or is it better to wait until Subarugears has done finished their testing with Subaru auto gear with transverse pinion.

Does the Vw automatic gear box manage the torque of the H6 motor?

Thanks.

[brokengun]

I have no direct experience here, so take all of this with a grain of salt. I follow some folks on social media who have H6 conversions and they're often having transmission issues and I don't think many with this conversion have gone the automatic route, although I'm sure it *could* be adapter to fit one. KEP sells an automatic adapter plate.

From what I understand a subarugears 5MT isn't a silver bullet either. One gent put one in only a few weeks later to have the ring and pinion fail. I can't speak for his driving style but some claim an additional plate is needed to stiffen up the case which must have some rib material removed in order to accommodate the reverse R&P. Not the first report I've heard of issues with the subarugears setup coupled to an H6 vanagon. If you want to go that route I'd try to find someone knowledgeable about options for re-enforcing the case.

Otherwise it seems like all the H6 conversion folks end up with a 4 speed transmission that is as overbuilt as possible. Personally, I would not put much stock in an auto trans cutting the mustard in this application.

Just my 2 cents, best of luck with your project!
_________________
1984 Vanagon Adventurewagen with EJ22 conversion
1975 Beetle - Big whole in the floorboards
1974 Westy - Will be on the road one day!
1973 Bus - sold

[ischias]

[vwhammer]

I am fairly certain that the adapter that mounts the 2.2 or 2.5 subaru engines to the auto trans will also mount the 6 cylinder engine.

As far as the auto handling the power here is some portion of my response that I copied and pasted in another thread.

It was my understanding that the auto trans was way more stout than the manual, even in stock trim.

You can also upgrade some internals to the Audi turbo trans bits but, after talking with Matt Steedle, he suggested that the Audi bits aren't even necessary for most of the engines that are put into these vans.

I don't know the HP and torque numbers for all the subaru H6 engines but Matt has a van with a 265hp Acura V6 in it using a Vanagon auto trans.

I don't believe he is running the Audi parts on that trans.
If I recall I also think he does a fair bit of drag racing with it too.

He has a couple vids on youtube of it doing a nice burnout and even pulling a front wheel on a launch or two.

This may not mean anything as it is just a few seconds of video and the trans may have exploded as soon as the camera was shut off but I am still fairly certain that the auto trans is stronger.

I should also mention that Matt is a proper transmission guy and probably knows all the tweaks and tricks to make the auto work and hold up.

If I was looking to connect some real power to an auto trans he would be the guy I would talk to.
_________________
Pretty normal daily driver build
https://www.thesamba.com/vw/forum/viewtopic.php?t=708418&highlight=

4x4 build
https://www.expeditionportal.com/forum/threads/volkswagen-vanagon-4x4-conversion.162055/

[ischias]

[Eric_Taylor]

I'm sure it's possible, considering the number of motor combinations that folks put in these vans. The bigger question really is what is your desired result and will this get you there?

I've got an auto and have spent a lot of time looking at motor swap options. First, the auto is only a 3 speed so even with a significant gearing change, I don't know that you're ever going to get a big top end, nor do I personally think i'd like driving a vanagon camper at 80 plus.

The next issue is keeping the temps down. This is the big one to me. I've seen a lot of discussion about this and it appears that your best shot is going with an external cooler that is run in front of the radiator. Rocky Mountain westy supplies a kit if I remember right and it's doable. However, regularly beating on that trans with over double the power is going to put a lot of heat and wear into it and you should be prepared for the possibility of it failing on you because of those factors.

To create any kind of reliability my research says you want to do a full rebuild with the Audi turbo internals. If your going with this much power, a new R&P is going to be dam near required to get the gearing to make any kind of sense with that motor. Without it you're going to be turning very high RPMS and that again creates issues with trans heat even if the motor can handle it.

In the end, to get the trans in it's best condition is just under $4k the last time I checked with the upgrades mentioned above. With the power of the H6 in either displacement, I think you're really still testing the limits of that rebuilt trans, so if you go down this route, it's important to be prepared for the possibility that you may even end up doing a second rebuild, which would be less as you're not buying the upgrades in round two.

At any rate, I think really high power and the auto becomes a gamble in a lot of ways, costs a lot to find out if you gambled right. I'm also not really sure what the driving experience would be like with only the 3 gears as well. Is the manual that much better? Maybe, but I don't know the answer there as i'm an auto guy in this vanagon world.

I think 150 hp or less appears to be the upper limit of making a nice driving experience with the Auto, assuming you still do the above upgrades so the gearing is matched and the trans is cooled and robust. Remember, though the "turbo" upgrade says turbo we are talking about an 80's audi turbo family sedan here, so I believe it's around 150hp at best and defiantly below 200hp. It's not today's turbo thinking, but it is a big bump from our stock 2.1.

That's my two cents. I don't see a lot written about swaps with the auto so I hope this helps. I've tried my best to distill all this down for myself. If this all works for you and you want to do the H6, please please please document your experience here. It would be great to be wrong and find out it's awesome!

[ischias]

[hisport]

It has been a few years, but a friend in VA put a 3.3L (SVX H6) behind a stock Vanagon auto trans (about the same time I did my SVX swap with a 4 speed; using higher 3rd and 4th gears). Only mod, I believe, was to governor for higher shift speed.
His '86? westy automatic drove fine; very strong, as a matter of fact. Problem was gearing. Even with tall tires, the SVX motor was spinning way too high on the highway (close to 4K at 70, IRRC). Loud, horrible gas mileage, tiring to drive.
(My 4sp SVX westy is around 2750 rpm at 70 mph; pretty smooth and composed - for a Vanagon, anyhow. Gas mileage never better than 18 mpg, though)
The H6 motors you are considering are far newer than the SVX lumps, yet I believe you may find that they're also designed to cruise at 3K or less

I'd love to have a nice modern electronic automatic in Ms Edie (rather than the old bread van 4 sp). Say, an Audi 8 speed or something similar. The modern Subaru engine ECU's would equally like to be conferring happily with their original TCU's (transmission control units). Even my '92 SVX ECU is lonely behind a 4 speed and really needs a TCU handshake. Not sure if this has been sorted out on the newer H6 conversions
Darryl at AA in Tacoma (RIP) did my (1.13/0.77 ? ) 4 speed, which has been reliable - using a KEP adaptor, HD clutch, flywheel - for 18K miles/8 years. Oh, and my VA buddy eventually put in a subaru 5 sp transaxle, which I haven't driven
Hope this info helps!

[ischias]