Reverse drive Subaru 5 speed for rear engine VW's now done.

[ttriebler]

Hi all,

I have developed a crownwheel & pinion set for the Subaru transmission that allow the differential to be 'flipped'. This provides 5 forward gears & 1 reverse gear.

This can be used as a 4wd gearbox or a 2wd gearbox converted from the 4wd gearbox. Using a 2wd Subaru shifter end cone this gearbox will fit into type 1 beetles without cutting the torsion bar.

At this stage only a 41 tooth crownwheel and 11 tooth pinion are available.

I developed a pancake forging for these components and they are forged out of en36c steel, the preferred material for gears. CNC machined, ground and heat treated, they are o.e.m. quality and finish.





Price of a crownwheel and pinion set is $1500usd + shipping from Sydney, Australia. A locking kit to lock the gearbox driven shaft and pinion shaft for 2wd applications is around $100 usd.

I have some in stock now for anyone wishing to put an affordable, strong 5 spd together. Ideally looking for some workshops to order these in quantity and provide their own 5spd kits with mounts, output flanges and shift linkages. I am not able to provide full kits. Volume discounts are available.

Subaru 4wd 8 bolt gearboxes (99 on) that these were designed for will hold 206kw stock. That's around 275hp. If you upgrade the gears for an extra $4000usd or so they will take 500kw or approx 650 hp. Gears in both synchro, dog box, straight cut and normal are all readily available.

Please contact me for any further information at [email protected]
I have also put together a website that provides more detail:

Reverse Cut Subaru Gears

regards

Todd Triebler
Dynamic Distribution

[petew]

great work mate. at last an alternative to 35yo weak gearboxes.

btw, what ratio is the final drive?

[ttriebler]

Final drive is 41/11

Check out all the details on my website :

www.members.iinet.net.au/~ttriebler

[55superbeetle]

Thats a pretty awesome piece you've produced. I'm currently putting a wrx transmission in a mid engine 914 using the bremmar sleeve to lock it into front wheel drive. Do you have any real data on how much torque the r&p can handle. In stock form the front final drive would only be taking half the torque being produced. I have a subaru buddy with 500awhp street wrx and he has never broken a ring and pinion, gears yes but not the final drive. This leads me to believe that they are stronger than they look especially in a way lighter car that a 1.5 ton Subaru. I really want to go this route in my subaru powered 55 bug but it raises some questions. If you look the price of getting a wrx box in the us your looking at about 700 minimum, 1600 to get your R&P, and at least another 500 for custom axles or flanges, not to mention a cable shifter and mounts. Thats 2800 allready, then tack on another 3 grand for a gearstack and it gets scary. In reality people would be more than willing to pay that much if it could honestly take some abuse with 350+ horsepower and have a true 5 speed. You have to realize though that that is a Mendeola and Porsche G50 price tag witch are both proven gearboxes. I guess in all this rambling I'm trying to say that if you had some proof or real world testing of the torque capability (you might already) I would be pretty serious about getting one of these from you

[ttriebler]

Hey thanks for the feedback. Some good points you've raised there.

If you're 'only' looking to put around 350hp through a box then you probably don't need to even look at an aftermarket gear stack. They take 206kw stock - that's 275hp. And that's Japanese factory rated kw (which is mostly understated). Plenty of WRX's here that make 200kw at all 4 wheels with stock drivetrains and make hard launches. Approx 350hp at the flywheel.

I have rarely heard of anyone breaking a crownwheel and pinion in these, even the WRC's use them with all their power. Now I know the diff will have twice the strain on it in 2WD mode but of course with half the weight of the vehicle, that evens the score again.

I am preparing a stock gearbox as a 2WD unit to be put into a sand rail powered by an Sti EJ25T. That puts out plenty of power and gobs of torque as you know. I'd say that will be enough "real world" testing to cast any doubt from any minds.

In the meantime, for anyone prepared to be an early adopter, I will guarantee the strength of the crownwheel & pinion for 12 months for any application up to 350 flywheel hp and 600nm of torque. As long as the installation of the diff is set up to factory Subaru specs on install and there are pictures of the set up with gear contact patterns visible. Should one break I would need photos and/or parts shipped to me for inspection before refund.

I will offer to refund 110% of the purchase price of my parts and refund the cost of your shipping both ways.

cheers

Todd

[geminidubber]

What a great product. i have been wanting this. been planning on doing a but with a subaru engine in it. but my biggest concern was always the strength of the trans. now i can pick up a fwd subie trans and engine "no adaptor needed " and 5 gears to boot. what has to be done for the axel shafts to be compatible with the vw? thanks again and great product.

[ttriebler]

Sorry geminidubber. You need a 4WD box converted to 2WD. The crownwheel shaft and gearbox gears on a 2WD box are a marginally different design to the crownwheel shaft and gearbox gears on a 4wd box. The 2wd box has gears going straight onto the crownwheel shaft whereas the 4wd box uses another shaft for the gears to go onto . The crownwheel shaft spins inside the gear shaft. Hence you need the locking kit to lock them together for 2wd.

I may be able to produce the 2wd crownwheel shaft in the future from my forging blanks but it would be a couple years away before/if it happens.

The 4WD boxes are way stronger anyway, go with one of those and you will be happy for ever. (but a little poorer).

To get the VW shafts to run inside the Subaru CV's you will have to look at getting them cut to teh right length and resplined. Any differential shop sould be able to do that for you.

[geminidubber]

cool man thanks for the info. as i have started working again ill soon be ordering a kit from you. sorry for the questions but what about shift linkage?

[petew]

Final drive is 41/11

Check out all the details on my website :

http://www.members.iinet.net.au/~ttriebler

so that's a 3:73 ratio. compared to the stock VW 3:88, that measure up well. You'd then just pick your ratios.

Does that R&P fit in a 6 speed sti box?

[ttriebler]

not sure if it fits in a 6 speed. Hard to get your hands on these and pul them apart, still quite rare and very expensive.
I think it's unlikely as they seem to have a fairly different design.

[PhillipM]

In the meantime, for anyone prepared to be an early adopter, I will guarantee the strength of the crownwheel & pinion for 12 months for any application up to 350 flywheel hp and 600nm of torque. As long as the installation of the diff is set up to factory Subaru specs on install and there are pictures of the set up with gear contact patterns visible. Should one break I would need photos and/or parts shipped to me for inspection before refund.

Now, I'm quite interested in this, as our existing boxes (UN5's) are getting harder to find in decent condition, do you have the gear ratios to hand for a standard 'box, as I suspect they may be too high for us (current box is running a 5.85:1 final drive..) - although, 1st is unusable at that and 2nd needs some respect, so...

[ttriebler]

OK guys firstly apologies on a small detail. The final drive ratio is actually 39 teeth to 10 teeth so 3.9 to 1. Stock VW 3.88 to 1.

I am confident of announcing additional ratios available by the end of the week, just ensuring that we don't weaken the teeth outside the envelope. Should range from 3.9 up to 5.9

Subaru WRX gear ratios are usually :

1st 3.166
2nd 1.882
3rd 1.296
4th 0.972
5th 0.738
rev 3.333

The Liberty and Forester boxes are a little wider spaced.

I've checked about the 6spd box today and the crownwheel and pinion design is definately a different one.

[petew]

I think we can forgive you for that. 3.88 is a good ratio for a lot of things. Anywhere where it's not, you could just get a low ratio gearset made up. Funny how close the subaru numbers are to VW stuff even after all this time. How much bigger/heavier is this box than the VW type 1 and bus boxes? I ask coz I think it makes a great 5 speed alternative for aircooled racers. Just be a case of getting an LSD for it I guess.

oh, are these trans as hard to work on as VW trans or are they more simple?

[ttriebler]

Easy to work on. modern 5 speed.

Weight as a 2wd 5 speed = 42kg or 93 lbs.
As comparison a Porsche G50 5 speed = 68kg or 150 lbs.
Renault UN1 = 57kg or 126 lbs.

Couldn't find the weight of a 6 rib 091. Anyone?

oh and the Subie is 1/2" shorter than the 091 bus box if fitted with the subie 2wd nosecone or 4wd nosecone chopped in half for 2wd use.

[PhillipM]

I am confident of announcing additional ratios available by the end of the week, just ensuring that we don't weaken the teeth outside the envelope. Should range from 3.9 up to 5.9

Brilliant, if you can, I reckon we shift a lot of those up here for all the higher-powered competition cars, there's dozens laid up because they're just fed up of replacing gearboxes.

Just a couple more questions then:

1) Where about does the shifter mechanism attach to the box, I had a look through the pictures but couldn't spot it, maybe I'm blind

2) Could you let me have the height from the centre of the output flanges the centreline of the engine input shaft so I can check to see where our engine would end up?

3) Any plans on doing some output flange adaptors for 930 CV's?

4) I'm not really a Subaru man, do you know if plate-type LSD's are readily available?

5) Do you know what RPM's the input shaft bearings are rated to, we had to uprate the UN5 ones.

6) Is there a blocker on 1st gear to prevent shifting down at higher speeds (with a 3.9 diff we'd need to use 1st for some of the fiddly sections, so we'd have to remove it, unless you get the higher diffs sorted..)