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Wed Sep 09, 2009 6:11 pm

Ok...seems I've switched transmissions from a bug to a 091 and also moved it from it's stock position, I don't think I can't just whip up standard "wider x longer" arms with my axles (with 20.25 it's a 5x5) since I've moved the trans from it's stock position.

What I've got to work with:

091 trans with type 4 cvs
trans has been moved back about 4 inches and has also been lowered
20.25 axles

With that said, I'm having a helluva time figuring out my geometry for my arms. When the cvs are on the axles I get 19.875" from cv face to cv face fully compressed and 20 11/16" fully extended.

Any suggestions on how I can get started?

Thu Sep 10, 2009 5:46 am

Well, after sleeping on it I don't think there's any good way other than mocking it in autodesk than making an adjustable jig.

I'm thinking of a something that pivots at the irs clip and also at the bearing carrier than can slide lengthwise.

Once it I get it fabbed up, I'll throw it on and find what setup gives me the maximum amount of travel with my axels, then make a jig off that jig.

Lotta work, but mistakes are the best teachers I suppose. I'll be sure to post some pictures as well.

Comments?

Thu Sep 10, 2009 12:06 pm

If you want to get me measurements of all the peices, I can draw it up in Autocad, and help you determine where it all needs to be.

Thu Sep 10, 2009 8:21 pm

I Guess I wonder about your set up! if your trans is 4 inches back and you want to run the same axles as the 5x5 than you would possibly go 9 inches longer and 5 wide... the arch would change and I so think I would draw the arch you have and the new arch and compare them.

With the greater arch you might not go back the whole 4 inches is my guess...

the guys at avery in Washington build some awsome/crazy custom arms and I am sure they would have the right answer for you! ask for todd

http://www.averysaircooled.com

Sun Sep 13, 2009 10:44 pm

It appears you are pre-supposing an axle length. What about the axle length when the axle is horizontal? An IRS arm does NOT travel in an arc parallel to the centerline of the car. The arm pivots angle at an angle through the center of the torsion bar/spring plate junction and the centr of the arm pivot bolt.

Why did the trans get moved back?

Why did the trans get moved down?

Is the cart dragging the horse around on this project?

Sun Sep 13, 2009 11:23 pm

dustymojave wrote: It appears you are pre-supposing an axle length. What about the axle length when the axle is horizontal? An IRS arm does NOT travel in an arc parallel to the centerline of the car. The arm pivots angle at an angle through the center of the torsion bar/spring plate junction and the centr of the arm pivot bolt.

Why did the trans get moved back?

Why did the trans get moved down?

Is the cart dragging the horse around on this project?

Right, I'm working backwards--axle length known first and the arms created around them.

Currently when the axle is level, there is 1/4" of slop in the axle, the bearing housing face is verticle with a slight 'toe-in', and the axle is perpendicular with the trans cv flange.

The trans got moved back for more travel (to allow for the axle to be perp with the trans cv flange when it's horizontal.

The trans got moved down for more ride height.

'cart dragging the horse'? havn't heard that one before! meaning the project is backwards i assume? well.. yeah it is, but a good way to save money by not having to screw with custom axles

Just swinging the arm until the cvs physically max out I'm getting 19" of travel--probably more like 16 or so when I get in my bumpstops

Mon Sep 14, 2009 5:19 am

saving money on axles might cost you alot on custom arms...? Once you have those custom arms you have to worry about running short on talent and then paying a bunch to re-jig that custom arm again. I would order a over the counter arm and sell your axles and order the correct size for the job. I think Manxman sells a great set of arms that are 5x6 that mount to everything stock if I remember cirrectly. Maybe check dansperformanceparts.com for pricing....

Just a thought!