Turbo trans to NA diff CHEAPER idea?? Someone has had to have thought of this before?
 

Okay, so I'm currently going through a TurboII swap, and am going to run a Tii tranny, but didn't want to switch out my NA rear end, because it's an expensive aftermarket 1.5 way.

I know you can buy the Tii tranny, to NA diff driveshafts for around $300??

I read a few threads saying that you can use the Auto driveshaft, as it has the yoke size of the Tii tranny, but the NA Diff PCD on the other side.

The problem with that is, it's ~1" too short?

So here's my idea.

Attachment 649489



Kinda like a billet wheel spacer adapter. But for the diff. Obviously.

What it would do is basically the same as the wheel spacer though. Retain the mounting holes, but push the driveshaft an inch in the correct direction.

Has anyone ever thought of this, or made something like this??

Please tell me this is a great idea :icon_tup::icon_tup:

Auto drive shafts can be had for like $30, and this adapter couldn't cost more than $50-60 to make. Meaning this would be a super cost effective solution right??

I am thinking there may be an issue with it not being balanced. If you could bolt the piece to the driveshaft as it woiuld be on the car then take it to a driveline shop and get the assembly balanced it might work.

why not take the Diff flange off and see where the holes correspond to the TII Driveshaft?
You can make the holes on the driveshaft Bigger(oval them) ..BUT fill in the old spot where the original TII bolts went through with a weld job.

Then again you got a $1k Diff in a N/A Rear end and you are complaining about matching it to a TII swapped car that cost you money to do.
Not to rag on ya but That statement is just to point out that if you are doing that much to the car you may as well Complete doing it RIGHT and don't fart with stuff that can be "iffy".

1: bought the car with the diff.
2: swap has taken me months to even begin. And am not even half way through. Not much money to play with
3: never once complained.


Okay so let me make my intentions a little more clear.

It can take forever to find a Tii driveshaft, and when you do find them. They're beat up, and cost a fortune. So a Tii shaft would just not be very cash friendly.

Also, many many people already use the $300 driveshaft. I'm simply trying to replace it with a $100 MAX solution. Who doesn't want to save $200??

There's tons of unwanted auto drive shafts that can be had for pocket change. Why not put them to use, and save money at the same time?

I bought a used t2 driveshaft and it had the holes ovaled out since he was using it on a NA rear end. I'm assuming he had no issues, and I'm using it fine now with a t2 rear.

I dont know about Tons of them being out there and in serviceable condition but let us know how it works out

Ya,I mentioned that,but Personally It doesn't sit well with my gut,so I don't fully suggest with doing it.
It can be done but not on my car.I still have a Driveshaft in my shed that someone did that oval hole mod to.
IDEA!:I may just get it welded up..sell it as a conversion.

I ran an ovaled out TII drive shaft to my NA rear end for a couple years with no issues. I recently swapped it out for a legit conversion shaft since I'm planning on selling the car and it will be one less thing to discuss with the next owner. When I swapped it out I saw no evidence of the ovaled out holes causing any issue with the bolts loosening up, or the flange shifting/spinning out of alignment/, or any other causes for concern that it was going to come apart and kill me.

beachFC - I'd ship you my ovaled holed TII drive shaft for the cost of shipping if you'd promise not to sue me if it all falls apart and maims or kills you. :lol:

^BAM. Done.

In the interest of science, the adapter idea could work. BUT it requires you to get two things right:

1. The adapter needs to be balanced. That means holes need to be machined and drilled very accurately and all the geometry is symmetrical. To do it perfectly, you'd need CNC machine time and/or balancing afterward. Basically you are building an tiny solid driveshaft, so it has the same balancing requirements.

2. Threads need to be cut straight, because fasteners don't like rotating, misaligned faces. Again, this is hard to do by hand.

Also consider the residual value of the parts if you do the TII diff swap. Your spacer is worth 0 dollars while the driveshaft could be sold for ~$150? You're not that much further in the hole.

exactly this part needs to be very accurate or it will vibrate,

my dad and I build a getto adapter back in the day and it had a ton of vibration, but it did allow us to at least get the car rolling, until proper items could be installed,

however strong vibration could put stress on the bolts and drivetrain and cause them to break,
you don't want your driveline exploding going 60 mph!

I've personally seen them sell for $10 in great condition. Where as I've seen TERRIBLE condition Tii driveshafts sell for $70. I mean BOTH u-joints had major play in them.


Mega down for that deal. But it's not gonna keep me from pursuing this spacer idea haha..


1: I have 3 buddies that work in machine shops, One at Jet engineering(who make parts for Boeing I believe?? not sure) and 2 at privately owned smaller shops.

2: I also work at NRG Innovations. The company that produces the hub adapter, and quick release steering wheel systems.. We have MORE than enough CNC machines at the ready hahaha :D The factory where our sh*t is made has about an acre of warehouse filled with them. But i'd only really go that route if they were going into production.



Again, I am NOT trying to come up with a completely new idea. The drive shaft is already 100% available, and in production. I am simply trying to come up with a easier, and more cost effective way to adapt the two driveline parts. How is nobody else on board?! :scratch::lol:

selling adapters might be profitable, id agree,

no ones on board cause all of us who are posting have already moved passed this point lol

make your adapter and become rich! if you sell enuf u can afford a new t2 diff and lsd! lol

we could call it the "son of a Beach FC driveshaft adapter!'

heresa drawing I modified,

use longer high grade bolts, then make a hole in the middle cuase the stock diff flang has a centering section that sticks out, and then make one that sticks out on the other end to go into the stock auto driveline.

like hubcentric wheel spacers,

Not worried about making profit. Of course that sounds interesting, but I've just never been that type of guy. More of the "pass on a deal to a fellow enthusiast" kinda guy. I'd really only want to charge enough to cover the cost of production.

As for the "not on board" deal.. I wonder why there was enough interest for a known company to spend big bucks, and produce an entirely new $300 drive-shaft, but not enough interest to make a $50 adapter. :scratch::scratch::scratch:



:nod: :icon_tup: "Son of a Beach!" sounds attractive ^_^

Aside from the bolt hole stuff, that was all part of the plan. I wanted it just like a hub-centric wheel spacer. I mentioned that in the first page, but included no detail. I guess I thought that everyone would have got that part :blush:

For some reason the longer bolts scare me. Seems like if you were to get even the SMALLEST amount of play, that the bolts would have enough force to snap like tooth picks, and ruin/oval the holes on all the pieces, and opposed to the ruining of two pieces if the bolts were to snap on the original plan.

Not sure if I'm way off on that one. But my mind seems to see it happening??

I dont know how the adapter will handle the driveshaft angle aspect of the operation , in my head it sounds like it would work , then I over think it and I picture vibrations

( CNC is simple for this, if guys cut wheel spacers for $50 a pair how much more complicated is threading some of the holes ? )

Well that's the thing. I WANT the holes threaded. As seen in the first picture.

As for vibration, I doubt there will be any to speak of.. not sure how off a forged billet aluminum spacer could even be. But probably next to nothing at all.

Because the factory driveshaft has non-replacable U-joints( I know there is a way to replace them but it requires some grinding and extra steps that true replacable ones don't). They "Mazdatrix" were already selling an aftermarket driveshaft with true replacable U-joints before the popularity of the TII swaps happened. So to sell one to adapt the two was just as simple as offering the option of the n/a flange on their TII shaft or vice/versa. Also from a liability standpoint the risk, even if small, of something failing on the adapter and getting sued over it if someone was injured was probably not worth the effort to develop it.

when going to the expense of a properly done swap, a driveshaft is a minor expense in the overall scheme of things

I can hate to pay for things as much as the next guy so I can appreciate some grassroots money saving techniques. Set one up and use it for a while and see what happens but you wouldnt be the first to say "hey how come they dont make a spacer"= maybe you need to be that guy who makes it

That does make sense. But my point is that, people BUY the thing. For $300. Is saving $250 a hassle?? I sure wouldn't mind.

As far as getting sued?? I highly highly doubt it.

Companies already sell a similar product, and even goes on the same section of the car(Drive line). Wheel spacers. If Daigo Saito can launch a 1200hp car running 285 Achiles 123's on an a 75mm!!! billet wheel spacer. I'm quite sure anyone doing a budget Tii swap can't come anywhere near the amount of power it takes to destroy one.

the guy that is such a cheap ass to buy this spacer cant afford an attorney, you could always just advertise this for off-road testing purposes only, use at own risk,as-is no liability bla bla

make it!

I never said anything about a hassle. I just stated why I think they sell driveshafts and not adapters. They already sold driveshafts. For them it was probably a phone call and/or a new drawing to their vender saying we want to order x-number of driveshats with this flange on them. This, I'm sure was less cost for them than developing and building a prototype and then testing the adapter before offering it for sale.

Even if there is no chance of failure which there could be even if as small as 0.1% lets say, you have to take it into account as a business.

Personal injury lawers usually get their cut from your settlement if you win your case thus you don't have to have any money to sue. They only get paid if you win. You lose they and you are S.O.L.

Don't misunderstand. I'm not telling him to not make it for his build or even sell a few if it works out. I was just saying why I think they don't sell adapters. His chances of getting sued may be almost 0, but some people see a successful business and they see $$$, and here comes the lawsuit even if there is no grounds for one.

Sorry for derailing the thread.

Just oval the bolt holes

Get a turbo2 drive shaft!Take off the NA flange off the diff and mate it 2 the turbo driveshaft.If you look carefully the flanges will be centered but the holes wont match.Clamp them down together and redrill oval the holes a little and your done.7 plus years off street racing,dyno pulls,drag racing and my setup was still running with the above mod and never had a vibration or anything!well i did destroy the NA rear end eventually did install a Turbo 2 diff....thanks 2 the newly found power after my REW RE hybrid swap.