Why T181 flanges
 

Got a question. Why do we need to put t181 flanges on an irs tranny when going to 944 rear arms? From what I see, the pattern is supposed to be the same as the T1. Is this another instance of overkill for strenght, or is it a dimensional thing?

Hello-

There are two seperate things to think about. First, the trailing arms and the geometry they give. There's no reason in the world this dictates new output shafts... it doesn't matter.

But, the second thing is CV size. All aluminum 944 arms have stub axles with the T2-sized CV, and the arms can't be "swapped" for smaller, T1-sized ones. All steel 944 arms also have stub axles with the T2-sized CV, but they _can_ be swapped for stock T1 stub axles. In either case, most of the time, an upgrade to bigger CVs is desired by the person putting in the trailing arms, so they get the tranny output shafts to match.

Take care,

So does a 181 flange mate up with a t1 or t2 cv. I'm just getting confused when I search the forums.

It matches up with the T2 CV.

Alex

Thanks Alex, it makes sence to me know.

So, are there no bus tranny flanges that would work in a t1 tranny?

No, but 181 flanges WOULD allow you to use bus CV's (big) or 944 CV's (bigger). Most of the racing transaxle shops have their own 181 type "conversion" outputs also but are more $$. You don't "have to" go away from T1 CV's at all unless you intend to abuse them (which I definately intend to do :D ).

A link to some comparisons of the different sizes of the CV's and axles.....
http://www.blindchickenracing.com/Ho...es_and_cvs.htm

i'm using 091 output shafts T2 cv's in my IRS tranny.

That's good news Pete. I had the understanding that the only way to adapt was with 181's.

so how do these different options in the use of CV's and axles translate to the added distance from the trans to the hub? assuming early alloy arms add 1 3/4" per side, where is that distance made up?

john and i are trying to figure out the right combination of parts to use, without overkill and unneeded additional cost but still doing the right thing.

i will have 176HP TIV, T1 RAT trans, IRS, early alloy 944 arms and spring plates. from other posts i have gathered this as one option:

trans > T1 output flange > T1 CV > T1 axle > T2 CV > 944 stub

sorry for so many questions in one post.

Good post zen.
I think we are all struggling with this..... well except for Shad who seems to have it all locked down:cool: !
The set-up you have listed seems straight forward. From what I gather, the axle is where you make up the distance and you may have to buy new ones at a specific length ($200:eek: I think)
I decided that I wanted the extra size of the 944 CV's for my long term HP plans but lots of drag guys still run the T1 CV's up to a certain HP/traction limits, several have posted that smart driving is the key regardless of the size of your "joint":silly: !

>i'm using 091 output shafts T2 cv's in my IRS tranny.<

How? I looked at this option and it seemed impossible as the splines are completely different.

As for the Thing output flanges they are not needed if as Panel said you are not beating the car hard off the line. Heck I think most people doing the CV conversion do not need it!

The reason I am switching to T2 CVs is that I need the greater working angle for the IRS bus suspension conversion. The T1 I think gives 18 degress where the T2 gives 22 or 24 degrees. The 411/412 gives the best but are hard to find. As I understood it the 944 used T2 CVs, but this is not verified.

The later 944s with AL arms used longer axles, find the ones that work or get SAW axles to match your needs. I think mine were 125ish for a pair.

the flanges are 091 to which the T2 cv's bolt to, then the beetle axle to another T2 cv, then to a beetle/T2 stub axle.

the tranny has Super Spline Drives which are thicker much like a T2/181 output shaft. the output side (spline side) mates with the 091 flange.

call kevin at KSR

he biult my trans and could tell you what's going on. i could be confused, getting things mixed up.

pete

good call pete. kevin is building me a trans brace right now. didn't even think to ask him. not sure if he has done any conversions to 944 arms though.

Pete's side gears in his t1 trans have been cut and spliced to 091 splines. I had a pair of these but were spliced to 002 bus splines and ran all t2 cvs then, most better trans people can supply these but I *think* Weddle or Transform is the source. My spliced side gears lasted until the next weak link broke-the spyder gears.

the spider gears in my tranny are 10 tooth. its been a year, but i remember Kevin saying he had to change them to a gear which have less teeth, which is stronger. i believe he also modified my sidecovers too. i think he got the super spline shafts from Weddle.