Going over a few material specs, and it looks like Im going to go with 6063 aluminium alloy, heat treated, and anodised for the drum. Strength and machine-ability are good. For the fork pillar, Im going with a high chrome ground bar. Something similar to a Damper (shock absorber) shaft. For the forks Im not that sure on yet, as to whether I go with a 2 piece design, that is, the fork, and the pillar shaft bush/bearing. Or a three piece design, where I use a dis-similar bearing metal for the fork parts contacting the synchroniser assembly. Ideally Id like to make the forks from aluminium but I have to look into that some more as I feel cast alloy could fail after sometime, and billet may deflect unless the fingers are quite bulky. Ill need to do the fork drawings and decide then once I see actual possible sizes. BG
From looking at many motorbikes and also knowing the stiffness of different materials I'd be looking at some form of steel. The size you can make them will be limited due to gear spacing and you don't want bendy shift forks.
Yes indeed Cast iron would be nice since it has bearing qualities as is. Or something forged too, but this is hard to do at home. So thats why Im thinking now going back on my word maybe cast lm25 heat treated with ribs for stiffness could be engineered to do the job. The ribs could possibly extend around the fork circumference for most of it, and give good support to the fingers/rebate that engages in groove. Ill have to do a few tests first. It is light and very easy work. More pics in a while
Pretty tight in there, but, once I plan the access slot it should ease things a bit. I have to study where the most stresses are to figure out the areas that can be taken out, and replaced in a different location to add case rigidity. Luckly the separation loads around the lower gears are taken by the main bellhousing case. BG
This is all way over my head at present but very interesting none the less, looking forward to seeing how this unfolds. Brilliant concept, best of luck
Thanks Roy, So Ive been doing a few rough sketches on how a modular unit could be added to the side of box, without effecting its structure, Ill do a few more before deciding on the best route, then Ill post it up I recently picked up the part in the link below, to study some machining issues I had been wondering about, http://www.clubgti.com/forum/showpost.php?p=2020167&postcount=1396 More soon
I saw this at a autosport show today: Looks alot like the Klaus Berner gearbox but with cnc'd housing shame about doing so much work to make a 02J seq and having the OEM clutch housing with weak spot were the input shaft is bolted to. They asked 10.000 euro for it!
nice - been thinking about doing something to my 085, but if I start running big power I'll probably bite the bullet and buy a motorsport gearbox
I was watching the 24hours of daytona there last night, they changed a sequential box in a matter of minutes, out on the ground, bare cogs and slotted the new one in.. deadly job..
Believe so - fits the 1.6 iron block, and the 1.4 is the same? 020 internals, barring any upgrades, ie big block + GTI gearboxes http://www.clubgti.com/forum/showthread.php?t=218706
probably a topic for a later date - once I've got a spare engine I'll see about getting one of these to mate up to it!
If you have an agricultural scrapyard nearby, the rod of a hydraulic ram should be a good donor for chrome bar.
Cant rememeber if I read anything about this in this thread (a while since i read it) but this looked interesting and kind of relevent. The VW shiftmatic gearbox http://www.volkspage.net/technik/ssp/ssp/SSP_372.pdf Slightly off topic but a good excuse for a bump .
