Subarugears instead of Porsche 915

trev

On my long-shelved EJ20T conversion into my oval beetle I have the engine on the floor, the DS tuning adapter kit attached and the Porsche 915 box sitting beside it.

I cut the middle out of a 1303 chassis years ago to bosh the lot into it, raised and pushed forwards to get it all under the rear decklid while maintaining some ground clearance. I now have a fresh semi-auto chassis (beam front, IRS rear) to use and I'm thinking of selling off the 915 and converting a Subaru gearbox using the Subarugears reverse cut crown wheel and pinion.

So I'm wondering, will selling the 915 and the adapter kit cover the cost of buying a Subaru trans and the Subarugears bits or should I start saving?

Is it a massive ball-ache to perform the reverse-drive conversion myself? Do I need specialist knowledge/tools? Should I start with a 4WD or 2WD transmission?

Having never seen a Subaru trans in the flesh I'm wondering is it shorter than the 915? Longer than a beetle trans? Does it use a hydraulic clutch? Push or pull type? Is there much cutting of the chassis required to make it fit?

I'm at the early stages of research so any help appreciated. Getting the gearbox sorted might be the shot-in-the-arm my long-stalled conversion needs to get it going again!!

Kai · Posted: Wed Sep 17, 2014 9:06 pm Post subject:

I sold my 915 for 2k to a bloke in Portugal via eBay. Was we'll chuffed. I'm yet to sell the adaptor plate and clutch. I didn't get on with the gearing with my WRX engine but then I just didn't get on with the 915 at all really. Getting shot of it was the best thing I've done for my conversion that and using the subaru speed sensor.

Speak to API subaru, I bought the subaru gears kit for £1300 ( only got stung £30 import duty) then spent a further £1k buying the rest of the bits from Api as I didn't have anything else. They supplied me with a 4wd ty754 transmission for £450+vat, I did the cutting and clearance work myself then the built it for me at that price. I bought a clutch and lightened flywheel, hydraulic slave and starter motor from them too. Oh and you can choose which gear set you prefer uk or jdm.

The ty754 ( do not even think about using a ty752 as it'll still cost you more only to convert it to a ty754 centre diff housing) compared to the 915, the ty754 is slightly shorter but is wider then the 915. I used the 915 front gearbox mount as it was already there, slightly modified it to fit the subaru box. Basically, the new nose / old centre diff housing is less bulky then the 915 nose cone.

I'd already cut the torsion bars out for my 915 install so I had ample room to squeeze it in plus my engine is rather forward then I guess would be usual if the torsion bar housing was still in place.
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trev · Posted: Wed Sep 17, 2014 11:18 pm Post subject:

thanks for the info Kai, that's a real help.

my real concern is that the 915 I have it a total unknown quantity and if I put all the work into modifying the chassis (again!) to make it fit and it turns out to be a pile of poo I don't think I could afford to have it rebuilt. If I build up the chassis with a reversed Subaru box and I break it then I should be able to pick up another for much smaller money than rebuilding the 915.

Kai · Posted: Sat Sep 20, 2014 6:30 am Post subject:

I never got a quote for mine! But I too fitted the box and it turned out to be crap. Admittedly I had a lot of modifications to mine and probably could of invested more time into setting it up but after trying for so long and the car being pretty undrivable I folded and went subaru gears. Simply for the fact that the only on line price I could find was £1700+vat to strip and inspect the box then repairs where on top of that. You can just tell the rebuild is going to run into the thousands. With that in mind, and after speaking to API about supplying the a box for £540 reconditioned, compared to 3-400 second hand price on eBay it seemed a safer route for me.

The subaru gear box fitted snugly into the place of e 915 apart from the subaru selecter but this is no doubt specific to my installation as I think my engine is further forward. If the 915 fits then you'll be able to get the subaru gears in there.

You won't be able to use the 915 drive shafts as they're about 25mm too long. I had mine shortened and reused the 944 cv joints. Also the subaru box is wider then the 915 at the diff housing, hence why you need shorter shaft.

Use the subaru ty754 electronic speed senser out of the gearbox. Must be the three pin version though.
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Kai · Posted: Sat Sep 20, 2014 6:32 am Post subject:

Also I think Todd sells the mounts to fit the subaru box into a beetle floor pan meaning you shouldn't have to modify your chassis too much.
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richbaker78 · Teacher of Padawans Joined: 31 Jan 2006 Posts: 1298

Hi trev, can't really comment on your specific box replacement however I'm doing a subarugears in my early bay - the box is lighter than a bay one and gears matched to the engine so boost etc will all be in the right place.

Costs so far for me £1200 to buy kit, but I got stung £300 on top for import so if you can get it posted as a gift of have another way to get it try to avoid it getting sent with a commercial invoice!!!!

I managed to pick up a ty754 box on ebay with clutch and hydro clutch and sensors for £250 so they are ot there if u can wait.

I intend to build the box myself ( how to coming soon on my thread ) and what I have done so far is defo diy able. Chopping down the casing etc is actually all very easy and I spent quite a while making a decent shifter set up but this will be much easier in your application.

Having been out in the van with my old box fitted to it which was a modified 091 I'm so glad I have gone for the proper box for the engine.

trev · Posted: Thu Oct 23, 2014 9:46 pm Post subject:

thanks Rich, that's good to know. Keep me posted on your progress. I have projects lined up for the forseeable but maybe by the time you've finished I'll be ready to start!!

re the Subaru ty754 box, which years were they available and in which models? What is it about that box that makes it more desirable? Something to do with the VSS?

Kai · Posted: Thu Oct 23, 2014 10:14 pm Post subject:

The ty754 is from the bug eye Subaru which I think is 2002> The early ty752 has a different centre differential housing which does not lend itself to the cutting and shortening require to fit it in the back of a VW. The ty752 can be used however you will need to source a ty754 centre diff housing and selector forks. Roughly £80 to buy the parts.

The speed sensor is something I've been championing as I didn't have any success with a speedo cable equivalent.

I've been doing some hard launches with my ty754 box and quaiffe diff and clearly I need new gearbox and engine mounts as something doesn't sound good but the box is taking all the abuse.
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richbaker78 · Teacher of Padawans Joined: 31 Jan 2006 Posts: 1298

Have you put the top mount on the box Kai? I did because I did wondered about the torque issue so I am glad you have confirmed my concerns. I used a bulkhead mount from a scooby outback ( same on legacy too )as it is steel and therefore weldable compared with he plastic or alloy version from the Impreza the box comes from.