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New 5th gear conversion

Posted: Sat Jun 15, 2024 9:40 am
by Bruce.m
You might need the auto translation subtitles because it’s in German. Bolt on conversion which fits the stock nose mount (either version).

https://youtu.be/ot54r-8iCO0?si=4MwwldHDEY7BMJZI

Re: New 5th gear conversion

Posted: Sat Jun 15, 2024 1:32 pm
by Chip Birks
That's cool!

Re: New 5th gear conversion

Posted: Sun Jun 16, 2024 2:34 am
by Ian Godfrey
Yep, and that front beam looks very interesting packaging as a Mendeola front beam has quite some bump steer, so with the rack up a bit higher it looks promising on that front. I wonder if there is a T1 version as well as a T3?
Back to the gear box. I was unable to work out if it used an extended pinion and main shaft or if it used a different solution to a Berg 5?

Re: New 5th gear conversion

Posted: Sun Jun 16, 2024 12:03 pm
by Bruce.m
The subtitles suggest it’s for t3 & t34 but they can produce a t1 version. It was a graduate thesis project for the designers “masters” qualification.

Re: New 5th gear conversion

Posted: Sun Jun 16, 2024 3:01 pm
by H2OSB
I watched with rapped attention. I understand very little German (as much as you can recall from 4 years of HS and two college semesters), but it looked very interesting.

H2OSB

Re: New 5th gear conversion

Posted: Sun Jun 16, 2024 3:25 pm
by Bruce.m
Press & hold the subtitle button. The pop up give you an option for “auto translate” select that & it give you one option (English)

Re: New 5th gear conversion

Posted: Mon Jul 01, 2024 3:18 am
by Bruce2
Ian Godfrey wrote: Sun Jun 16, 2024 2:34 am I was unable to work out if it used an extended pinion and main shaft or if it used a different solution to a Berg 5?
I think these are the shaft extenders:

Image

And then installed, you can see the socket head screws to hold them on.

Image

Re: New 5th gear conversion

Posted: Mon Jul 01, 2024 8:20 am
by Bruce.m
Well spotted. That will reduce the price significantly if it’s not a custom main shaft & pinion shaft. Load limits would be an interesting debate. Tricky machining operation since I assume the ends of the shafts need drilled & tapped? Those will be hard steel too.

Re: New 5th gear conversion

Posted: Sat Aug 03, 2024 7:28 am
by Dubveedub
I think the Subaru with r&p swap is a great setup, but not having to source a different trans, the flipped parts, and an adapter makes the 5 speed upgrade for stock trans look like the way to go.

Re: New 5th gear conversion

Posted: Wed Aug 21, 2024 7:35 am
by Piledriver
The reversed Subaru trans setup makes a great deal of sense if you are also doing a Subaru motor swap.

As long as its 5th gear in the nosecone instead of first as in a 914/901 the loadings would probably be fine.

6061T6 front plates are available for 914/901 trans to help keep things together.

Re: New 5th gear conversion

Posted: Mon Oct 21, 2024 4:45 am
by Bruce.m
Bit more details are available on the 5th gear conversion. An insta video shows closer details of the parts & design.

CAD cutaway shows the bolt on shaft extensions.

Price though is a lot. Circa €4.5k which is a shame.

https://dastriebwerk.com/dtw-fuenfgang-umbausatz

Re: New 5th gear conversion

Posted: Mon Oct 21, 2024 4:48 am
by Bruce.m
Image

Re: New 5th gear conversion

Posted: Mon Oct 21, 2024 6:15 pm
by Piledriver
How much are the alternatives?
Only ones that come to mind are 901s or Mendeola at ~$6-7K used
The 901 will still cost $$$$ to rebuild, and they are all 40-50 years old.?
You could probably score a later model low mile Porsche trans for less, but they are a lot longer.
Same for the Audi units.

A 090 automatic would potentially take far more power, but there go the frame horns and IRS only.

Re: New 5th gear conversion

Posted: Mon Oct 21, 2024 11:43 pm
by Bruce.m
“Shame”. Because its more than I’m happy to spend on a 5th gear.

Given the complex billet parts, its probably a reasonable price. Splined hard shaft extensions for example are not a simple piece to make.

Its not clear if the cost includes modifying the pinion shaft & the input shaft, or even if they are included (drilled & tapped for the extension pieces). But i suspect you need to get your own parts modified.

I do have a 60s 901 transmission core which i bought for very little a long time ago, but the rules for classic car mods have been tightened up recently so any non standard welding or even holes on the floorpan can result in the car being deregistered permanently with no appeal or reversal option. So it not worth the risk.