901 weak links and, my 901 is apart and I want to get it in proper order to handle a LOT o Options

[RXBeetle]

First post, noob here! Hello all and thanks for letting me in on your fun.
I have a 74 Super Beetle.... ok you can all stop laughing now. (914 someday, but for now I like my Bug) I am in the process of upgrading from a stock VW trans and a 12A rotary engine to a turbo 13B (~300hp and 250ft/lb of torque) and a 901 transaxle. I am sending some engine parts out for nidriding and I would like to get in as many parts as I can while I am at it that may benifit from the treatment. I am aware of the first gears lack of support and was thinking that having the drive and pinion shaft nitrided to make them less prone to deflection (I will still be gentle, not a drag car). I am a little worried about the diff since it's only a 2 spider and a Quaife is not in the budget. I think nitriding the diff housing should help reduce flex and keep the pinion gears fully engaged. I will probably have the pinion gears done as well. Now I'll admit that this is the first trans I have had apart and I am not familiar with what is prone to failure and what is fine for these power levels. In the Type 1 world you always hear the welded keyed 3rd and 4th, super diff, heavy duty side cover, etc. So if any one has some good info on how to beef up a 901 that would be greeeeat
PS anyone have a 901 nose cone from a 911 laying around???
PPS who ever had the red 914 out at the woodward dream cruise yesterday (IMG:style_emoticons/default/aktion035.gif) very nice, very clean, kick ass.

Thanks!

[RXBeetle]

Thanks for the replys guys, I had a couple hourse over a pint of the black stuff to mull my plans over.

There are a few reasons I did not go with a 915. Costs 3X what my 901 ran me, 901 in a beetle is pretty straight forward and bolts right up to my adaptor kit and flywheel (not sure the 915 would even fit in the limited space), I think my clutch, tires, and CV joints, and fear will all give way before I hurt the 901.

If the gears and diff themselves are plenty strong then I am not worried about it, these are just typical weak points in the type 1 and get a bit stuck in my head as things to look to impove. I have a bad habit of finding failure modes the hard way. If I can pick some experienced brains I might save myself the trouble and hopefully find a workable sollution.

As to the intermediate plate... I have seen the billet numbers on ebay and thought about just making my own (got the machine shop and a billet of 6061 big enough sittin on the rack... don't tempt me) The way I see it the suspected cause of the plate flexing is due to the bearing pivoting in it's seat as the drive shaft flexes because the loaded gears are trying to push away from eachother. If the force is great enough to flex that plate then a more rigid plate would just flex less and cause the bearing to bind even harder. The gears may not disengage as much but I would have to assume that bearing damage would still be done and the bearing seat would get pounded out in no time. I could be totaly wrong though, wouldn't be the first time or the last.

kdfoust you are correct it is a surface treatment that alters the surface structure of the metal. I have read that nitriding will help lower the elastic modulus and increase tensile strength in the affected region. If that is ture it should reduce the ability of the shaft to deflect (like a three point tensile test). On the other hand I reeeeealy don't want to pull the whole gear stack apart...

Oh god my ramblings are gettin long... I'll stop now haha have a good one

[kdfoust]

<SNIP>

kdfoust you are correct it is a surface treatment that alters the surface structure of the metal. I have read that nitriding will help lower the elastic modulus and increase tensile strength in the affected region. If that is ture it should reduce the ability of the shaft to deflect (like a three point tensile test). On the other hand I reeeeealy don't want to pull the whole gear stack apart...

Oh god my ramblings are gettin long... I'll stop now haha have a good one

Keep in mind the affected region is likely to be only a few thousandths of an inch deep from the surface of the part. Not likely enough to be of practical significance. I'd have a discussion with my supplier to see what recomendations they would make based on the known failure modes.

Good luck,
Kevin