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.

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

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!!

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