Subaru transmission questions- need specifics

Hello from Florida!
I'm working on a way to use different transmissions in bugs busses and beetles; particularly Subarus due to their popularity and I need some help. Can anyone tell me the overall length of the subaru transmissions and the length of the subaru axles per your most popular models for swap? I think I have an acceptable method of using the stronger drivelines from the Subaru cars. Also, does anyone know the length and width of the VW transmissions?? I do have one but I haven't removed it yet to measure and this info would be helpful if it is known.
Thanks in advance!
Rob

Hey Rob, 2WD or 4WD? BBy far the most common Subaru transmissions downunder are the 4WD ones. I can get you the length of those if that's what you're after. By the way, in their standard form their length means that you have to cut the torsion bars to fit them.

However a 2WD version is a different story, or a 4WD version with the centre diff removed to make it 2WD is also very short and would most likely not need the torsion bars cut.

Let me know which you are after and I can take some measurements for you.

Yeah, may the force be with him 😂

Thanks ttreibler, I'm looking for the 2wd models for my own project but eventually I'm looking for all of them. If my plan is correct, you'll be able tgo use any of them(what you do with the other end is up to you). I know it has been attempted to use the subaru trans before with disasterous results but I think I have a new handle on this. .......by the way seagull, why the long face?? 😁

The only way you can do it is to fit the motor behide your front seat . Mike it Perth has done it & I had a look today , he is running a WRX motor as well. I take some photos next time I am down that way and post them up . The front is running A arms and coil overs , fully cadged out

Cool, I'd like to see them seagull. I do understand what you are saying but I think I have a solution for the configuration. I don't want to get anyone's hopes up until I can get the bugs worked out of my design but there IS a way to use this configuration in the typical VW fashion. I will elaborate as things develop, I promise.

1) your thinking of turning the crown wheel over
2) your thinking of flipping the gear box up side down
3) your thinking of getting a new crown wheel & pinon made
4) your thinking using the above and fitting a Front lsd center

5 = 🙄

😁 NONE OF THE ABOVE!!! 😁

What I can tell you is that it HAS been done before in other applications and not for this purpose specifically but it should work nonetheless.

Reverse rotation cams? a la corvair?

It's also possible to use planetary gears to reverse rotations. This could be done via an adapter plate between motor and gearbox or via the output shafts to reverse their rotation. I also looked into putting planetary gears on the input shaft of the low/high range Subaru gearboxes as they have a split input shaft. This can be achieved however those gearboxes have teenny weeny input shafts and wouldn't be up to the task of handling any power.

Good luck to you as many have gone before and failed.

Let me know when you wish to purchase your first set of reverse-cut crownwheel and pinion/output shafts from me.
I'll give you a great price shipped to your door in Florida.

Suffice it to say that what I have in mind has been proven to handle quite a bit of torque in other apps so I think it will work. I just want to test it first, then, once I know it will work, I'll fill you all in on it. I promise. As far as the measures of the transmissions go, are the Subaru transmissions longer, wider or both than a type 1 trans?❓

The 2WD ones are very very similar in dimensions to a type 1 trans. They fit inbetween the frame horns so aren't any wider.

what about using reduction boxes as per a splitty? dont these reverse the rotation of the transaxle? M

Yes they do but they 'jack up' the suspension on application of throttle. Not a great handling characteristic.

ttriebler wrote:It's also possible to use planetary gears to reverse rotations. This could be done via an adapter plate between motor and gearbox or via the output shafts to reverse their rotation. I also looked into putting planetary gears on the input shaft of the low/high range Subaru gearboxes as they have a split input shaft. This can be achieved however those gearboxes have teenny weeny input shafts and wouldn't be up to the task of handling any power.

Good luck to you as many have gone before and failed.

Let me know when you wish to purchase your first set of reverse-cut crownwheel and pinion/output shafts from me.
I'll give you a great price shipped to your door in Florida.

Ok ,

If you have made the gear set I would love to have a chat about what you have done. The gear set I have seen was so crap it went 18 feet and snaped the pinion like a twig.

Well this guy did it

http://www.vwkd.co.uk/bb/viewtopic.php?t=1962

Edit Just realised it's not back to front, sorry

ttriebler wrote:Yes they do but they 'jack up' the suspension on application of throttle. Not a great handling characteristic.

There are ways to "full float" the RGBs so that you don't get that effect. Think of an old style BMW motorcycle versus the newer paralever setup.

I've seen pictures of a Brasilian RGB IRS setup that has possibilities. The parts are probably unobtainium, though.

What about inboard reductions, they wouldn't effect the handling, could set up high/low or foward/aft even depending on application.

Hey guys,
I was doing some brainstorming with a buddy of mine this evening and we're putting some sketches together right now. Thanks ttreibler for the info on the width of the trans; I think it will become useful shortly. I've got a friend with an older (early 90's) Legacy non-turbo that he'll donate for free- running and all so I have the most important part for the experiment. It is an automatic car so at least it will make shift linkage easy. I'll get back with you all soon and let you all in on this as soon as I make sense of it all.

Hey the idea of inboard reduction hubs is pretty awesome. You could have them so they are 'behind' the trans output. This would likely minimise the 'jacking up' effect and also alow the trans/motor to be further forward. The other alternative would be a planetary gearbox on the output. Rugged and compact.

Hey guys, time for an update... I've got my boxes roughly designed and now I'm looking for alittle input on straight cut gears and their strengths and weaknesses. If anyone has any input or can recommend a differing type of gear, please let me know. My boxes are roughed out so I can alter dimensions to suit my gear sizes so I am not limited to one particular size or ratio. Thanks for the input and all your help in advance. As promised, I'll keep everyone updated as I go.
Rob

helical cut is actually stronger and better for most applications.

Hi Orange
The strength of a helical cut is much higher than a straight cut OF THE SAME TOOTH PROFILE, but straight cuts usually have much larger teeth and can be cut more easily from higher strength materials. One problem is that straight cut gears, and larger teeth, make a lot of noise and that's why car manufacturers don't use them. They love gutless little engines with quiet little fine cut gears running to the limit of the strength of their cheap materials.
BUT, to the main reason racing boxes have straight cut gears. Helical gears try to slide sideways across each other (think about it) and therefore create side load on the bearings and thrust washers. This creates heat and the box fails by either overheating, which weakens and breaks gears, or the thrust washers fail and the box falls apart. Put in straight cuts and all the load is taken straight against the bearings as they were designed to take it. The “noise” (vibration) is hard on the bearings with heavy loads but you change them out regularly and the box lives, cool, strong & noisy.
For what you want build it first with straight cuts and see how it goes, they’re cheaper to machine and will give less trouble, and bore noise. I’m sure your gear man will advise you on what’s best for your design. Good luck. I look forward to seeing the results.
Cheers
Tony

Thanks guys for the interest and info. I was thinking along those lines for the strenght part but I was more worried about my box design. In an effort to keep them affordable and "bulletproof", I was planning on the straight cut gears pretty much. I'm wondering how thick they will need to be to handle the HP of the nastiest application. If I can prepare the boxes for the worst application, I think they'll be great for us all. Besides; whose worried about alittle gear noise anyway?? With most of these Suby cars out there, you'd be hard pressed to hear the gears over the exhaust anyhow! Well, bear with me and I'll get an update with some fresh news about construction as soon as I can and thanks again to you all for all your help!
Rob

P.S. does anyone know what the highest HP of these Subaru conversions is out there?? I don't have any idea so let me know. THANKS!!

P.S. does anyone know what the highest HP of these Subaru conversions is out there?? I don't have any idea so let me know. THANKS!!

With reasonably stock engines the turbo models go a bit over 300. With mods some say they can triple that. How fast do you want to spend? 🙂

Yawn !

nothing here

Sorry to bore you seagull but I'm not equipped with a full service machine shop... And, do you want it fast or correct!? As before, bear with me folks, I'm doing this on a serious shoestring budget.

The problem with using reduction boxes is you lower the efficiency of the driveline, meaning less power at the wheels. Straight cut gears are more efficient than helical gears, but you will still have some losses. For this reason I don't see the reduction box solution very suitable for street cars that are chasing performance. So if you are only using it to reverse the rotation, but not lower the gearing, then I see it as being full of disadvantages.

For an offroader you can have the benefit of lowering the gearing, so you might accept the loss of efficiency.

That's just my thoughts 👍

This is going no were

seagull wrote:This is going no were

Many times I have gone nowhere yet found the trips to be quite enjoyable! 🙂

Hi George , I few over you house the other day


I think to date I have seen every kind of *working* gear box set up , the best I have seen in countrys UN5 transaxel with a 9" ford LSD diff in a custom housing. I get a photo of this as it was made in a back yard shed.It holds up to a 400kw nissan turbo motor

seagull wrote:Hi George , I few over you house the other day


I think to date I have seen every kind of *working* gear box set up , the best I have seen in countrys UN5 transaxel with a 9" ford LSD diff in a custom housing. I get a photo of this as it was made in a back yard shed.It holds up to a 400kw nissan turbo motor

I never cease to be astounded by the backyard ingenuity that pops out now and then. Sometimes the result is humorous, sometimes remarkable.

Unfortunately, around here most of the people who need really strong transaxles just get out their Visa card and head for Mendeola. They make great stuff, but I can't justify that sort of money for my hobby vehicles.

There's a 914 that's been sitting under a tarp up the street for years. Now if I could convince that guy to sell it I'd have a Subaru engine and transaxle installed in very short order! 🙂

Well this thread seems to have gone dead as usually is the case when people find out how hard it really is to use the Subi box. So...just to keep you punters interested, here's a lil pic of a reverse cut crownwheel and pinion manufactured and being checked for hypoid. Hopefully one day soon it will be completed and land on these fair shores..

been following with interest for use in a syncro powered by an ej20 turbo down the track. Do you think it will carry the extra weight compared to beetle the syncro is currently on it 2nd box rebuild costing $4.500 the owner has purchased 2 other syncro's for the transmissions oh yea of little faith
keep up the process for it has got to pay of in the end
Ernie

I'm still workin on this everybody! I'm having alittle trouble finding straight cut gears ( I've decided to go this way for the ease[?] of locating them.) that are strong enough to use. Anybody have any suggestions?? I'm planning on cutting out the centers of the straight cuts to insert a center to fit my axle stub.

Keep at it orange spitfire, these things are not easy to solve. My reverse cut crownwheel and pinion gears to suit the Subaru transaxle are on their way to me new so we may be building a box next week for imminent destructive testing. I have a feeling they might go in front of an EJ257 motor.

Hey all, the reverse-cut crownwheel and pinion sets are now available to build Subaru transaxles and stick em in the back of VW chassis of all sorts. The ratio is 41/11.

There are a couple of different ways to build them depending on whether or not you need them short enough to fit into a beetle without cutting the torsion bars. Using a 4WD box with the 2wd Subaru nosecone achieves this.

I have put together a website outlining the basics :
Subaru Reverse Cut Gears

Take a look and let me know what you think.

Looks great, well done to you for going through with this venture, now all the hard work is done you should be selling them like hot cakes 👍👍

4WD Super Baja sound too easy now 🙂

Sounds really good what you've been able to achieve 👍👍
Have you tested this in either form as yet? 2wd/4wd
Cheers

ttriebler wrote:Hey all, the reverse-cut crownwheel and pinion sets are now available to build Subaru transaxles and stick em in the back of VW chassis of all sorts. The ratio is 41/11.

There are a couple of different ways to build them depending on whether or not you need them short enough to fit into a beetle without cutting the torsion bars. Using a 4WD box with the 2wd Subaru nosecone achieves this.

I have put together a website outlining the basics :
Subaru Reverse Cut Gears

Take a look and let me know what you think.

...any test done with this box as yet?....this would be the best way for sales...

seagull wrote:Hi George , I few over you house the other day


I think to date I have seen every kind of *working* gear box set up , the best I have seen in countrys UN5 transaxel with a 9" ford LSD diff in a custom housing. I get a photo of this as it was made in a back yard shed.It holds up to a 400kw nissan turbo motor

yes yes UN5😎

What !

Like this !

Nice!!! that UN1 looks stuffed in there nice and snug!

To answer people's questions, no we haven't had the chance to test a gearset in a vehicle yet, just built one into a gearbox.
I'm currently building one up into a 2wd box which we will install into a buggy for testing & documentation.
Will also give us a chance to maybe develop a complete kit of mounts, shifter and so on to install into type 1 pans with Subie motor.
Judging by the measurements, the 2wd box will not need torsion bar cutting and will also get a Subie motor forward enough for the cam covers on the quad cam motors to clear the tinware on a beetle.

In the meantime, we want to build up the number of installed boxes out there in different vehicles. I'm guaranteeing them for 12 months in installs of up to 350hp with a replace or 110% money back guarantee. I'll also cover the cost of shipping both ways if it fails.

That will be good enough for some to jump in and give it a try and others will want to sit back and wait to see the proof. That's cool too.

350hp gearbox is a big figure untested!......
I like the way ur thinking outside the square😊 but for these boxes to be proven and to sell ...proof in the pudding is wat people want.....

So do u have a total$ on the box forsale?

Yep I am confident of the crownwheel and pinion manufacturing quality. It's design up to 350hp and beyond is already proven in the thousands of WRX's running 260kw+ atw. Remember, all we did was flip the diff, didn't change any tooth profile. I cannot gurantee the entire gearbox to a rated hp as I don't supply gearboxes, only crownwheels and pinions. However there's plenty of them out there holding it and more if fitted with aftermarket gears.

As you say though, the proof is in the pudding so I gotta build up my test gearboxes. Getting some 2wd nosecones tonight so I should have a 4 bolt and 8 bolt test box built fairly soon. These will not be for sale, they are to document the process and then fit into my manx.

matberry wrote:What !

Like this !

No Matt , nothing like that I will get a photo soon

Promises, promises.